Book review: “A Big Bang in a Little Room” by Zeeya Merali

A Big Bang in a Little Room: The Quest to Create New Universes
Zeeya Merali
Basic Books (February 14, 2017)

When I heard that Zeeya Merali had written a book, I expected something like a Worst Of New Scientist compilation. But A Big Bang in A Little Room turned out to be both interesting and enjoyable, if maybe not for the reason the author intended.

If you follow the popular science news on physics foundations, you almost certainly have come across Zeeya’s writing before. She was the one to break news about the surfer dude’s theory of everything and brought black hole echoes to Nature News. She also does much of the outreach work for the Foundational Questions Institute (FQXi).

Judged by the comments I get when sharing Zeeya’s articles, for some of my colleagues she embodies the decline of science journalism to bottomless speculation. Personally, I think what’s decaying to speculation is my colleagues’ research, and if so then Nature’s readership deserves to know about this. But, yes, Zeeya is frequently to be found on the wild side of physics. So, a book about creating universes in the lab seems in line.

To get it out of the way, the idea that we might grow a baby universe has, to date, no scientific basis. It’s an interesting speculation but the papers that have been written about it are little more than math-enriched fiction. To create a universe, we’d first have to understand how our universe began, and we don’t. The theories necessary for this – inflation and quantum gravity – are not anywhere close to being settled. Nobody has a clue how to create a universe, and for what I am concerned that’s really all there is to say about it.

But baby universes are a great excuse to feed real science to the reader, and if that’s the sugar-coating to get medicine down, I approve. And indeed, Zeeya’s book is quite nutritious: From entanglement to general relativity, structure formation, and inflation, to loop quantum cosmology and string theory, it’s all part of her story.

The narrative of A Big Bang in A Little Room starts with the question whether there might be a message encoded in the cosmic microwave background, and then moves on to bubble- and baby-universes, the multiverse, mini-black holes at the LHC, and eventually – my pet peeve! – the hypothesis that we might be living in a computer simulation.

Thankfully, on the latter issue Zeeya spoke to Seth Lloyd who – like me – doesn’t buy Bostrom’s estimate that we likely live in a computer simulation:

“Arguments such as Bostrom’s that hinge on the assumption that in the future physically evolved cosmoses will be outnumbered by a plethora of simulated universes, making it vastly more likely that we are artificial intelligences rather than biological beings, also fail to take into account the immense resources needed to create even basic simulations, says Lloyd.”

So, I’ve found nothing to complain even about the simulation argument!

Zeeya has a PhD in physics, cosmology more specifically, so she has all the necessary background to understand the topics she writes about. Her explanations are both elegant and, for all I can tell, almost entirely correct. I’d have some quibbles on one or the other point, eg her explanation of entanglement doesn’t make clear what’s the difference between classical and quantum correlations, but then it doesn’t matter for the rest of the book. Zeeya is also careful to state that neither inflation nor string theory are established theories, and the book is both well-referenced and has useful endnotes for the reader who wants more details.

Overall, however, Zeeya doesn’t offer the reader much guidance, but rather presents one thought-provoking idea after the other – like that there are infinitely many copies of each of us in the multiverse, making every possible decision – and then hurries on.

Furthermore, between the chapters there are various loose ends that she never ties together. For example, if the creator of our universe could write a message into the cosmic microwave background, then why do we need inflation to solve the horizon problem? How do baby universes fit together with string theory, or AdS/CFT more specifically, and why was the idea mostly abandoned? It’s funny also that Lee Smolin’s cosmological natural selection – an idea according to which we should live in a universe that amply procreates and is hence hugely supportive of the whole universe-creation issue  – is mentioned merely as an aside, and when it comes to loop quantum gravity, both Smolin and Rovelli are bypassed as Ashtekhar’s “collaborators,” (which I’m sure the two gentlemen will just love to hear).

For what I am concerned, the most interesting aspect of Zeeya’s book is that she spoke to various scientists about their creation beliefs: Anthony Zee, Stephen Hsu, Abhay Ashtekar, Joe Polchinski, Alan Guth, Eduardo Guendelman, Alexander Vilenkin, Don Page, Greg Landsberg, and Seth Lloyd are familiar names that appear on the pages. (The majority of these people are FQXi members.)

What we believe to be true is a topic physicists rarely talk about, and I think this is unfortunate. We all believe in something – most scientists, for example believe in an external reality – but fessing up to the limits of our rationality isn’t something we like to get caught with. For this reason I find Zeeya’s book very valuable.

About the value of discussing baby universes I’m not so sure. As Zeeya notes towards the end of her book, of the physicists she spoke to, besides Don Page no one seems to have thought about the ethics of creating new universes. Let me offer a simple explanation for this: It’s that besides Page no one believes the idea has scientific merit.

In summary: It’s a great book if you don’t take the idea of universe-creation too seriously. I liked the book as much as you can possibly like a book whose topic you think is nonsense.

[Disclaimer: Free review copy.]

Book review reviewed: “The Particle Zoo” by Gavin Hesketh

The Particle Zoo: The Search for the Fundamental Nature of Reality
By Gavin Hesketh
Paperback Edition
Quercus (15 Jun. 2017)

A few weeks ago, I reviewed Gavin Hesketh’s book The Particle Zoo. I found his introduction to quantum field theory very well done. Considering that he can’t rely on equations, Hesketh gets across a lot of details (notably, what Feynman diagrams do and don’t depict).

However, I was quite unhappy with various inaccuracies in the book, particularly concerning the search for physics beyond the standard model.

But then something amazing happened! Hesketh sent me an email a few days ago, saying he read my review and revised the manuscript for the paperback edition to address the criticism. While the changes between the two editions will not be large, it usually doesn’t take more than a sentence or two to add some context or a word of caution. And so, I’m happy to endorse the paperback edition of The Particle Zoo which (according to amazon) will appear on June 15th.

Book rant: “Universal” by Brian Cox and Jeff Forshaw

Universal: A Guide to the Cosmos
Brian Cox and Jeff Forshaw
Da Capo Press (March 28, 2017)
(UK Edition, Allen Lane (22 Sept. 2016))

I was meant to love this book.

In “Universal” Cox and Forshaw take on astrophysics and cosmology, but rather than using the well-trodden historic path, they offer do-it-yourself instructions.

The first chapters of the book start with every-day observations and simple calculations, by help of which the reader can estimate eg the radius of Earth and its mass, or – if you let a backyard telescope with a 300mm lens and equatorial mount count as every-day items – the distance to other planets in the solar system.

Then, the authors move on to distances beyond the solar system. With that, self-made observations understandably fade out, but are replaced with publicly available data. Cox and Forshaw continue to explain the “cosmic distance ladder,” variable stars, supernovae, redshift, solar emission spectra, Hubble’s law, the Herzsprung-Russell diagram.

Set apart from the main text, the book has “boxes” (actually pages printed white on black) with details of the example calculations and the science behind them. The first half of the book reads quickly and fluidly and reminds me in style of school textbooks: They make an effort to illuminate the logic of scientific reasoning, with some historical asides, and concrete numbers. Along the way, Cox and Forshaw emphasize that the great power of science lies in the consistency of its explanations, and they highlight the necessity of taking into account uncertainty both in the data and in the theories.

The only thing I found wanting in the first half of the book is that they use the speed of light without explaining why it’s constant or where to get it from, even though that too could have been done with every-day items. But then maybe that’s explained in their first book (which I haven’t read).

For me, the fascinating aspect of astrophysics and cosmology is that it connects the physics of the very small scales with that of the very large scales, and allows us to extrapolate both into the distant past and future of our universe. Even though I’m familiar with the research, it still amazes me just how much information about the universe we have been able to extract from the data in the last two decades.

So, yes, I was meant to love this book. I would have been an easy catch.

Then the book continues to explain the dark matter hypothesis as a settled fact, without so much as mentioning any shortcomings of LambdaCDM, and not a single word on modified gravity. The Bullet Cluster is, once again, used as a shut-up argument – a gross misrepresentation of the actual situation, which I previously complained about here.

Inflation gets the same treatment: It’s presented as if it’s a generally accepted model, with no discussion given to the problem of under-determination, or whether inflation actually solves problems that need a solution (or solves the problems period).

To round things off, the authors close the final chapter with some words on eternal inflation and bubble universes, making a vague reference to string theory (because that’s also got something to do with multiverses you see), and then they suggest this might mean we live in a computer simulation:

“Today, the cosmologists responsible for those simulations are hampered by insufficient computing power, which means that they can only produce a small number of simulations, each with different values for a few key parameters, like the amount of dark matter and the nature of the primordial perturbations delivered at the end of inflation. But imagine that there are super-cosmologists who know the String Theory that describes the inflationary Multiverse. Imagine that they run a simulation in their mighty computers – would the simulated creatures living within one of the simulated bubble universes be able to tell that they were in a simulation of cosmic proportions?”

Wow. After all the talk about how important it is to keep track of uncertainty in scientific reasoning, this idea is thrown at the reader with little more than a sentence which mentions that, btw, “evidence for inflation” is “not yet absolutely compelling” and there is “no firm evidence for the validity of String Theory or the Multiverse.” But, hey, maybe we live in a computer simulation, how cool is that?

Worse than demonstrating slippery logic, their careless portrayal of speculative hypotheses as almost settled is dumb. Most of the readers who buy the book will have heard of modified gravity as dark matter’s competitor, and will know the controversies around inflation, string theory, and the multiverse: It’s been all over the popular science news for several years. That Cox and Forshaw don’t give space to discussing the pros and cons in a manner that at least pretends to be objective will merely convince the scientifically-minded reader that the authors can’t be trusted.

The last time I thought of Brian Cox – before receiving the review copy of this book – it was because a colleague confided to me that his wife thinks Brian is sexy. I managed to maneuver around the obviously implied question, but I’ll answer this one straight: The book is distinctly unsexy. It’s not worthy of a scientist.

I might have been meant to love the book, but I ended up disappointed about what science communication has become.

[Disclaimer: Free review copy.]

Book review: “Anomaly!” by Tommaso Dorigo

Anomaly! Collider Physics and the Quest for New Phenomena at Fermilab
Tommaso Dorigo
World Scientific Publishing Europe Ltd (November 17, 2016)

Tommaso Dorigo is a familiar name in the blogosphere. Over at “A Quantum’s Diary’s Survivor”, he reliably comments on everything going on in particle physics. Located in Venice, Tommaso is a member of the CMS collaboration at CERN and was part of the CDF collaboration at Tevatron – a US particle collider that ceased operation in 2011.

Anomaly! Is Tommaso’s first book and it chronicles his time in the CDF collaboration from the late 1980s until 2000. This covers the measurement of the mass of the Z-boson, the discovery of the top-quark and the – eventually unsuccessful – search for supersymmetric particles. In his book, Tommaso weaves together the scientific background about particle physics with brief stories of the people involved and their – often conflict-laden – discussions.

The first chapters of the book contain a brief summary of the standard model and quantum field theory and can be skipped by those familiar with these topics. The book is mostly self-contained in that Tommaso provides all the knowledge necessary to understand what’s going on (with a few omissions that I believe don’t matter much). But the pace is swift. I sincerely doubt a reader without background in particle physics will be able to get through the book without re-reading some passages many times.

It is worth emphasizing that Tommaso is an experimentalist. I think I hadn’t previously realized how much the popular science literature in particle physics has, so-far, been dominated by theorists. This makes Anomaly! a unique resource. Here, the reader can learn how particle physics is really done! From the various detectors and their designs, to parton distribution functions, to triggers and Monte Carlo simulations, Tommaso doesn’t shy away from going into all the details. At the same time, his anecdotes showcase how a large collaboration like CDF – with more than 500 members – work.

That having been said, the book is also somewhat odd in that it simply ends without summary, or conclusion, or outlook. Given that the events Tommaso writes about date back 30 years, I’d have been interested to hear whether something has changed since. Is the software development now better managed? Is there still so much competition between collaborations? Is the relation to the media still as fraught? I got the impression an editor pulled the manuscript out under Tommaso’s still typing fingers because no end was in sight 😉

Besides this, I have little to complain about. Tommaso’s writing style is clear and clean, and also in terms of structure – mostly chronological – nothing seems amiss. My major criticism is that the book doesn’t have any references, meaning the reader is stuck there without any guide for how to proceed in case he or she wants to find out more.

So should you, or should you not buy the book? If you’re considering to become a particle physicist, I strongly recommend you read this book to find out if you fit the bill. And if you’re a science writer who regularly reports on particle physics, I also recommend you read this book to get an idea of what’s really going on. All the rest of you I have to warn that while the book is packed with information, it’s for the lovers. It’s about how the author tracked down a factor of 1.25^2 to explain why his data analysis came up with 588 rather than 497 Z \to b\bar b decays. And you’re expected to understand why that’s exciting.

On a personal note, the book brought back a lot of memories. All the talk of Herwig and Pythia, of Bjorken-x, rapidity and pseudorapidity, missing transverse energy, the CTEQ tables, hadronization, lost log-files, missed back-ups, and various fudge-factors reminded me of my PhD thesis – and of all the reasons I decided that particle physics isn’t for me.

[Disclaimer: Free review copy.]

Book Review: “The Particle Zoo” by Gavin Hesketh

The Particle Zoo: The Search for the Fundamental Nature of Reality
By Gavin Hesketh
Quercus (1 Sept. 2016)

The first word in Gavin Hesketh’s book The Particle Zoo is “Beauty.” I read the word, closed the book, and didn’t reopen it for several months. Having just myself finished writing a book about the role of beauty in theoretical physics, it was the absolutely last thing I wanted to hear about.

I finally gave Hesketh’s book a second chance and took it along on a recent flight. Turned out once I passed the somewhat nauseating sales pitch in the beginning, the content considerably improved.

Hesketh provides a readable and accessible no-nonsense introduction to the standard model and quantum field theory. He explains everything as well as possible without using equations.

The author is an experimentalist and part of the LHC’s ATLAS collaboration. The Particle Zoo also has a few paragraphs about how it is to work in such large collaborations. Personally, I found this the most interesting part of the book. Hesketh also does a great job to describe how the various types of particle detectors work.

Had the book ended here, it would have been a well-done job. But Hesketh goes on to elaborate on physics beyond the standard model. And there he’s clearly out of his water.

Problems start when he begins laying out the shortcomings of the standard model, leaving the reader with the impression that it’s non-renormalizable. I suspect (or hope) he wasn’t referring to non-renormalizability but maybe Landau poles or the non-convergence of the perturbative expansion, but the explanation is murky.

Murky is bad, but wrong is worse. And wrong follows. Fore example, to generate excitement for new physics, Hesketh writes:

“Some theories suggest that antimatter responds to gravity in a different way: matter and antimatter may repel each other… [W]hile this is a strange idea, so far it is one that we cannot rule out.”

I do not know of any consistent theory that suggests antimatter responds differently to gravity than matter, and I say that as one of the three theorists on the planet who have worked on antigravity. I have no idea what Hesketh is referring to in this paragraph.

It does not help that “The Particle Zoo” does not have any references. I understand that a popular science book isn’t a review article, but I would expect that a scientist at least quotes sources for historical facts and quotations, which isn’t the case.

He then confuses a “Theory of Everything” with quantum gravity, and about supersymmetry (SuSy) he writes:

“[I]f SuSy is possible and it makes everything much neater, it really should exist. Otherwise it seems that nature has apparently gone out of its way to avoid it, making the equations uglier at the same time, and we would have to explain why that is.”

Which is a statement that should be embarrassing for any scientist to make.

Hesketh’s attitude to supersymmetry is however somewhat schizophrenic because he later writes that:

“[T]his is really why SuSy has lived for so long: whenever an experiment finds no signs of the super-particles, it is possible merely to adjust some of these free parameters so that these super-particles must be just a little bit heavier, just a little bit further out of reach. By never being specific, it is never wrong.”

Only to then reassure the reader

“SuSy may end up as another beautiful theory destroyed by an ugly fact, and we should find out in the next years.”

I am left to wonder which fact he thinks will destroy a theory that he just told us is never wrong.

Up to this point I might have blamed the inaccuracies on an editor, but then Hesketh goes on to explain the (ADD model of) large extra dimensions and claims that it solves the hierarchy problem. This isn’t so – the model reformulates one hierarchy (the weakness of gravity) as another hierarchy (extra dimensions much larger than the Planck length) and hence doesn’t solve the problem. I am not sure whether he is being intentionally misleading or really didn’t understand this, but either way, it’s wrong.

Hesketh furthermore states that if there were such large extra dimensions the LHC might produce microscopic black holes – but he doesn’t mention with a single word that not the faintest evidence for this has been found.

When it comes to dark matter, he waves away the possibility that the observations are due to a modification of gravity with the magic word “Bullet Cluster” – a distortion of facts about which I have previously complained. I am afraid he actually might not know any better since this myth has been so widely spread, but if he doesn’t care to look at the subject he shouldn’t write a book about it. To round things up, Hesketh misspells “Noether” as “Nöther,” though I am willing to believe that this egg was laid by someone else.

In summary, the first two thirds of the book about the standard model, quantum field theory, and particle detectors are recommendable. But when it comes to new physics the author doesn’t know what he’s talking about.

Update April 7th 2017: Most of these bummers have been fixed in the paperback edition.

Book Review, “Why Quark Rhymes With Pork” by David Mermin

Why Quark Rhymes with Pork: And Other Scientific Diversions
By N. David Mermin
Cambridge University Press (January 2016)

The content of many non-fiction books can be summarized as “the blurb spread thinly,” but that’s a craft which David Mermin’s new essay collection Why Quark Rhymes With Pork cannot be accused of. The best summary I could therefore come up with is “things David Mermin is interested in,” or at least was interested in some time during the last 30 years.

This isn’t as undescriptive as it seems. Mermin is Horace White Professor of Physics Emeritus at Cornell University, and a well-known US-American condensed matter physicist, active in science communication, famous for his dissatisfaction with the Copenhagen interpretation and an obsession with properly punctuating equations. And that’s also what his essays are about: quantum mechanics, academia, condensed matter physicists, writing in general, and obsessive punctuation in particular. Why Quark Rhymes With Pork collects all of Mermin’s Reference Frame columns published in Physics Today from 1988 to 2009, updated with postscripts, plus 13 previously unpublished essays.

The earliest of Mermin’s Reference Frame columns stem from the age of handwritten transparencies and predate the arXiv, the Superconducting Superdisaster, and the “science wars” of the 1990s. I read these first essays with the same delighted horror evoked by my grandma’s tales of slide-rules and logarithmic tables, until I realized that we’re still discussing today the same questions as Mermin did 20 years ago: Why do we submit papers to journals for peer review instead of reviewing them independently of journal publication? Have we learned anything profound in the last half century? What do you do when you give a talk and have mustard on your ear? Why is the sociology of science so utterly disconnected from the practice of science? Does anybody actually read PRL? And, of course, the mother of all questions: How to properly pronounce “quark”?

The later essays in the book mostly focus on the quantum world, just what is and isn’t wrong with it, and include the most insightful (and yet brief) expositions of quantum computing that I have come across. The reader also hears again from Professor Mozart, a semi-fictional character that Mermin introduced in his Reference Frame columns. Several of the previously unpublished pieces are summaries of lectures, birthday speeches, and obituaries.

Even though some of Mermin’s essays are accessible for the uninitiated, most of them are likely incomprehensible without some background knowledge in physics, either because he presumes technical knowledge or because the subject of his writing must remain entirely obscure. The very first essay might make a good example. It channels Mermin’s outrage over “Lagrangeans,” and even though written with both humor and purpose, it’s a spelling that I doubt non-physicists will perceive as properly offensive. Likewise, a 12-verse poem on the standard model or elaborations on how to embed equations into text will find their audience mostly among physicists.

My only prior contact with Mermin’s writing was a Reference Frame in 2009, in which Mermin laid out his favorite interpretation of quantum mechanics, Qbism, a topic also pursued in several of this book’s chapters. Proposed by Carl Caves, Chris Fuchs, and Rüdinger Sachs, Qbism views quantum mechanics as the observers’ rule-book for updating information about the world. In his 2009 column, Mermin argues that it is a “bad habit” to believe in the reality of the quantum state. “I hope you will agree,” he writes, “that you are not a continuous field of operators on an infinite-dimensional Hilbert space.”

I left a comment to this column, lamenting that Mermin’s argument is “polemic” and “uninsightful,” an offhand complaint that Physics Today published a few months later. Mermin replied that his column was “an amateurish attempt” to contribute to the philosophy of science and quantum foundations. But while reading Why Quark Rhymes With Pork, I found his amateurism to be a benefit: In contrast to professional attempts to contribute to the philosophy of science (or linguistics, or sociology, or scholarly publishing) Mermin’s writing is mostly comprehensible. I’m thus happy to leave further complaints to philosophers (or linguists, or sociologists).

Why Quark Rhymes With Pork is a book I’d never have bought. But having read it, I think you should read it too. Because I’d rather not still discuss the same questions 20 years from now.

And the only correct way to pronounce quark is of course the German way as “qvark.”

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[This book review appeared in the November 2016 issue of Physics Today.]

I’ve read a lot of books recently

[Reading is to writing what eating is to...]

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Dreams Of A Final Theory: The Scientist's Search for the Ultimate Laws of Nature
Steven Weinberg
Vintage, Reprint Edition (1994)

This book appeared when I was still in high school and I didn’t take note of it then. Later it seemed too out-of-date to bother, but meanwhile it’s almost become a historical document. Written with the pretty explicit aim to argue in favor of the Superconducting Supercollider (a US-proposal for a large particle collider that was scraped in the early 90s), it’s the most flawless popular science book about theoretical physics I’ve ever come across.

Weinberg’s explanations are both comprehensible and remarkably accurate. The book contains no unnecessary clutter, is both well-structured and well written, and Weinberg doesn’t hold back with his opinions, neither on religion nor on philosophy.

It’s also the first time I’ve tried an audio-book. I listened to it while treadmill running. A lot of sweat went into the first chapters. But I gave up half through and bought the paperback which I read on the plane to Austin. Weinberg is one of the people I interviewed for my book.

Lesson learned: Audiobooks aren’t for me.

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Truth And Beauty – Aesthetics and Motivations in Science
Subrahmanyan Chandrasekhar
University of Chicago Press (1987)

I had read this book before but wanted to remind me of its content. It’s a collection of essays on the role of beauty in physics, mostly focused on general relativity and the early 20th century. Along historical examples like Milne, Eddington, Weyl, and Einstein, Chandrasekhar discusses various aspects of beauty, like elegance, simplicity, or harmony. I find it too bad that Chandrasekhar didn’t bring in more of his own opinion but mostly summarizes other people’s thoughts.

Lesson learned: Tell the reader what you think.

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Truth or Beauty – Science and the Quest for Order
David Orrell
Yale University Press (2012)

In this book, mathematician David Orrell argues that beauty isn’t a good guide to truth. It’s an engagingly written book which covers a lot of ground, primarily in physics, from helocentrism to string theory. But Orrell tries too hard to make everything fit his bad-beauty narrative. Many of his interpretations are over-the-top, like his complaint that

 “[T]he aesthetics of science – and particularly the “hard” sciences such as physics –have been characterized by a distinctly male feel. For example, feminist psychologists have noted that the classical picture of the atom as hard, indivisible, independent, separate, and so on corresponds very closely to the stereotypically masculine sense of self. If must have come as a shock to the young, male, champions of quantum theory when they discovered that their equations describing the atom were actually soft, fuzzy, and uncertain –in other words, stereotypically female.”

He further notes that many male physicists like to refer to nature as “she,” that Gell-Mann likes the idea of using particle accelerators to penetrate deeper (into the structure of particles), and quotes Lee Smolin’s remark that “the most cherished goal in physics, as in bad romance novels, is unification.” This is just to illustrate the, erm, depth of Orrell’s arguments.

In summary, it’s a nice book, but it’s hard to take Orrell’s argument seriously. Or maybe the whole thing was a joke to begin with.

Lesson learned: Don’t try to explain everything.

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The End Of Physics - The Myth Of A Unified Theory
David Lindley
Basic Books (1994)

This is a strange book. While reading, I got the impression that the author is constantly complaining about something, but it didn’t become clear to me what. Lindley tells the story of how physicists discovered increasingly more fundamental and also more unified laws of nature, and how they are hoping to finally develop a theory of everything. This, so he writes, would be the end of physics. Just that, as he explains in the next sentence, it of course wouldn’t be the end of physics.

Lindley likes words and likes to use a lot of them. Consequently the book reads like he wanted to cram in the whole history of physics, from the beginning to the end, with him having the last word.

His argument for why a theory of everything would remain a “myth” is essentially that it would be hard to test, something that nobody can really disagree on. But “hard to test” doesn’t mean “impossible to test,” and Lindley is clearly out of his water when it comes to evaluating experimental prospects of, say, probing quantum gravity, so he sticks with superficial polemics. Of course the book is 20 years old, and I can’t blame the author for not knowing what’s happened since, but from today’s perspective his rant seems baseless.

In summary, it’s a well-written book, but it has a fuzzy message. (Also, the reprint quality is terrible.)

Lesson learned: If you have something to say, say it.

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Why Beauty Is Truth – A History of Symmetry
Ian Stewart
Basic Books (2007)

This is a book, not about the physics, but the mathematics of symmetries, symmetry groups, Lie groups, Lie algebras, quaternions, global symmetries, local symmetries, and all that. Steward also discusses the relevance of these structure for physics, but his emphasis is on it being an application of mathematics. The book is held together by stories of the mathematicians who lead the way. The title of the book is somewhat misleading. Steward actually doesn’t discuss much the question “why” beauty is truth. He merely demonstrates along examples that many truths are beautiful.

It’s a pretty good book, both interesting and well-written, if somewhat too long for my taste. It doesn’t seem to have gotten the attention it deserves.

Lesson learned: It’s hard to write a popular science book that anyone will still recall a decade later.

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Eyes On The Sky: A Spectrum of Telescopes
Francis Graham-Smith
Oxford University Press (2016)

This is a book about telescopes, from then to now, from the radio regime to gamma rays. It’s not a book about astrophysics, it’s not a book about cosmology, and it’s not a book about history. It’s a book about telescopes. It is a thoroughly useful book, full of facts and figures and images, but you need to be really interested in telescopes to get through it. I read this book because I wanted to write a paragraph about the development of modern telescopes but figured I didn’t actually know much about modern telescopes. Now I’m much wiser.

Lesson learned: If you need to read a 200 pages book to write a single paragraph, you’ll never get done.

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Beauty and Revolution in Science
James McAllister
Cornell University Press (1999)

Philosopher James McAllister reexamines the Kuhnian idea of paradigm changes. He proposes that it should be amended, and argues that what characterizes a revolution is not the change of the entire scientific paradigm, but merely the change of aesthetic ideals. To back up his argument, he discusses several historical cases. This is not a popular science book, and it’s not always the most engaging read, but I have found it to be very insightful. It is somewhat unfortunate though that he didn’t spend more time illuminating the social dynamics that goes with the prevalence of beauty ideals in science.

Lesson learned: Philosophy isn’t dead.

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Higher Speculations
Helge Kragh
Oxford University Press (2011)

Kragh’s is a book about the failure of speculative ideas in physics. The steady state universe, mechanism, cyclic models of the universe, and various theories of everything are laid out in historical perspective. I have found this book both interesting and useful, but some parts are quite heavy reads. Kragh doesn’t offer an analysis or draws a lesson, and he mostly restrains from judgement. He simply tells the reader what happened.

Lesson learned: Even smart people sometimes believe really strange things.

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Supersymmetry: Unveiling The Ultimate Laws Of Nature
Gordy Kane
Basic Books (2001)

Particle physicist Gordon Kane explains why the supersymmetric extension of the standard model has become so popular and how it could be tested. Whether or not you are convinced by supersymmetry, you get to learn a lot about particle physics. It’s a straight-forward pop-science book that does a good job explaining why theorists have spent so much time on supersymmetry.

Lesson learned: You don’t need to write fancy to write well.

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Nature’s Blueprint - Supersymmetry and the Search for a Unified Theory of Matter and Force
Dan Hooper
Smithsonian (2008)

A book about high energy particle physics, the standard model, unification and the appeal of supersymmetry. It’s a well-written book that gives the reader a pretty good idea how particle physicists work and think. Hooper does a great job getting across the excitement that comes with the hope of being about to discovery a new fundamental law of nature. The book’s publication date was well timed, just before the LHC started taking data.

Lesson learned: Your book might become history faster than you think.

Book Review: “Why String Theory?” by Joseph Conlon

Why String Theory?
By Joseph Conlon
CRC Press (November 24, 2015)

I was sure I’d hate the book. Let me explain.

I often hear people speak about the “marketplace of ideas” as if science was a trade show where researchers sell their work. But science isn’t about manufacturing and selling products, it’s about understanding nature. And the sine qua non for evaluating the promise of an idea is objectivity.

In my mind, therefore, the absolutely last thing that scientists should engage in is marketing. Marketing, advertising, and product promotion are commercial tactics with the very purpose of affecting their targets’ objectivity. These tactics shouldn’t have any place in science.

Consequently, I have mixed feelings about scientists who attempt to convince the public that their research area is promising, with the implicit or explicit goal of securing funding and attracting students. It’s not that I have a problem with scientists who write for the public in general – I have a problem with scientists who pass off their personal opinion as fact, often supporting their conviction by quoting the number of people who share their beliefs.

In the last two decades this procedure has created an absolutely astonishing amount of so-called “science” books about string theory, supersymmetry, the multiverse and other fantasies (note careful chosen placement of commata), with no other purpose than asking the reader to please continue funding fruitless avenues of research by appealing to lofty ideals like elegance and beauty.

And indeed, Conlon starts with dedicating the book to “the taxpayers of the UK without whom this book could never have been written” and then states explicitly that his goal is to win the favor of taxpayers:

“I want to explain, to my wonderful fellow citizens who support scientific research through their taxes, why string theory is so popular, and why, despite the lack of direct empirical support, it has attained the level of prominence it has.”

That’s on page six. The prospect of reading 250 pages filled with a string theorists’ attempt to lick butts of his “wonderful fellow citizens” made me feel somewhat nauseous. I put the book aside and instead read Sean Carroll’s new book. After that I felt slightly better and made a second attempt at Why String Theory?

Once I got past the first chapter, however, the book got markedly better. Conlon keeps the introduction to basic physics (relativity and quantum theory) to an absolute minimum. After this he lays out the history of string theory, with its many twists and turns, and explains how much string theorists’ understanding of the approach has changed within the decades.

He then gets to the reasons why people work on string theory. The first reason he lists is a chapter titled “Direct Experimental Evidence for String Theory” which consists of the single sentence “There is no direct experimental evidence for string theory.” At first, I thought that he might have wanted to point out that string theorists work on it despite the lack of evidence, but that the previous paragraph accidentally made it look as if he, rather cynically, wanted to say that the absence of evidence is the main reason they work on it.

But actually he returns to this point later in the book (in section 10.5), where he addresses “objections made concerning connection to experiment” and points out very clearly that even though these are prevalent, he thinks these deserve little or no sympathy. This makes me think, maybe he indeed wanted to say that he suspects the main reason so many people work on string theory is because there’s no evidence for it. Especially the objection that it is “too early” to seek experimental support for string theory because the theory is not fully understood he responds to with:

“The problem with this objection is that it is a time-invariant statement. It was made thirty years ago, it was made twenty years ago, it was made a decade ago, and it is made now. It is also, by observation, an objection made by those who are uninterested in observation. Muscles that are never used waste away. It is like never commencing a journey because one is always waiting for better modes of transportation, and in the end produces a community of scientists where the language of measurement and experiment is one that may be read but cannot be spoken.”

Conlon writes that he himself isn’t particularly interested in quantum gravity. His own research is finding evidence for moduli fields in cosmology, and he has a chapter about this. He lists the usual arguments in favor of string theory, that it connects well to both general relativity and the standard model, that it’s been helpful in deriving some math theorems, and that now there is the AdS/CFT duality by help of which one might maybe one day be able to describe some aspect of the real world.

He somehow forgets to mention that the AdS/CFT predictions for heavy ion collisions at the LHC turned out to be dramatically wrong, and by now very few people think that the duality is of much use in this area. I actually suspect he just plainly didn’t know this. It’s not something that string theorists like to talk about. This omission is my major point of criticism. The rest of the book seems a quite balanced account, and he restrains from making cheap arguments of the type that the theory must be right because a thousand people with brains can’t be mistaken. Conlon even has a subsection addressing Witten-cult, which is rather scathing, and a hit on Arkani-Hamed gathering 5000 citations and a $3 million price for proposing large extra dimensions (an idea that was quietly buried after the LHC ruled it out).

At the end of the book Conlon has a chapter addressing explicit criticisms – he manages to remain remarkably neutral and polite – and a “fun” chapter in which he lists different styles of doing research. Maybe there’s something wrong with my sense of humor but I didn’t find it much fun. It’s more like he is converting Kuhn’s phases of “normal science” and “revolution” into personal profiles, trying to reassure students that they don’t need to quantize gravity to get tenure.

Leaving aside Conlon’s fondness of mixing up sometimes rather odd metaphors (“quantum mechanics is a jealous theory... it has spread through the population of scientific theories like a successful mutation” – “The anthropic landscape... represents incontinence of speculation joined to constipation of experiment.” – “quantum field theorists became drunk on the new wine of string theory”) and an overuse of unnecessary loanwords (in pectore, pons asinorum, affaire de coer, lebensraum, mirabile dictum, for just to mention a few), the book is reasonably well written. The reference list isn’t too extensive. This is to say in the couple of cases in which I wanted to look up a reference it wasn’t listed, and the one case I wanted to check a quotation it didn’t have an original source.

Altogether, Why String Theory? gives the reader a mostly fair and balanced account of string theory, and a pretty good impression for just how much the field has changed since Brian Greene’s Elegant Universe. I looked up something in Greene’s book the other day, and found him complaining that the standard model is “too flexible.” Oh, yes, things have changed a lot since. I doubt it’s a complaint any string theorist dare raise today.

In the end, I didn’t hate Conlon’s book. Maybe I’m getting older, or maybe I’m getting wiser, or maybe I’m just not capable of hating books.

[Disclaimer: Free review copy.]

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Win a copy of Why String Theory by Joseph Conlon!

I had bought the book before I was sent the review copy, and so I have a second copy of the book, entirely new and untouched. You can win the book if you are the first to answer this question correctly: Who was second author on the first paper to point out that some types of neutrino detectors might also be used to directly detect certain candidate particles for dark matter? Submit answer in the comments, do not send an email. The time-stamp of the comment counts. (Please only submit an answer if you are willing to send me a postal address to which the book can be shipped.)

Update: The book is gone!

Book review: “The Big Picture” by Sean Carroll

The Big Picture: On the Origins of Life, Meaning, and the Universe Itself
Sean Carroll
Dutton (May 10, 2016)

Among the scientific disciplines, physics is unique: Concerned with the most fundamental entities, its laws must be respected in all other areas of science. While there are many emergent laws which are interesting in their own right – from neurobiology to sociology – there is no doubt they all have to be compatible with energy conservation. And the second law of thermodynamics. And quantum mechanics. And the standard model better be consistent with whatever you think are the neurological processes that make you “you.” There’s no avoiding physics.

In his new book, The Big Picture Sean explains just why you can’t ignore physics when you talk about extrasensory perception, consciousness, god, afterlife, free will, or morals. In the first part, Sean lays out what, to our best current knowledge, the fundamental laws of nature are, and what their relevance is for all other emergent laws. In the later parts he then goes through the consequences that follow from this.

On the way from quantum field theory to morals, he covers what science has to say about complexity, the arrow of time, and the origin of life. (If you attended the 2011 FQXi conference, parts will sound very familiar.) Then, towards the end of the book, he derives advice from his physics-based philosophy – which he calls “poetic naturalism” – for finding “meaning” in life and finding a “good” way to organize our living together (scare quotes because these words might not mean what you think they mean). His arguments rely heavily on Bayesian reasoning, so you better be prepared to update your belief system while reading.

The Big Picture is, above everything, a courageous book – and an overdue one. I have had many arguments about exactly the issues that Sean addresses in his book – from “qualia” to “downwards causation” – but I neither have the patience nor the interest to talk people out of their cherished delusions. I’m an atheist primarily because I think religion would be wasting my time, time that I’d rather spend on something more insightful. Trying to convince people that their beliefs are inconsistent would also be wasting my time, hence I don’t. But if I did, I almost certainly wouldn’t be able to remain as infallibly polite as Sean.

So, I am super happy about this book. Because now, whenever someone brings up Mary The Confused Color Scientist who can’t tell sensory perception from knowledge about that perception, I’ll just – politely – tell them to read Sean’s book. The best thing I learned from The Big Picture is that apparently Franck Jackson, the philosopher who came up with The Color Scientist, eventually conceded himself that the argument was wrong. The world of philosophy indeed sometimes moves! Time then, to stop talking about qualia.

I really wish I had found something to disagree with in Sean’s book, but the only quibble I have (you won’t be surprised to hear) is that I think what Sean-The-Compatibilist calls “free will” doesn’t deserve being called “free will.” Using the adjective “free” strongly suggests an independence from the underlying microscopic laws, and hence a case of “strong emergence” – which is an idea that should go into the same bin as qualia. I also agree with Sean however that fighting about the use of words is moot.

(The other thing I’m happy about is that, leaving aside the standard model and general relativity, Sean’s book has almost zero overlap with the book I’m writing. *wipes_sweat_off_forehead*. Could you all please stop writing books until I’m done, it makes me nervous.)

In any case, it shouldn’t come as a surprise that I agree so wholeheartedly with Sean because I think everybody who open-mindedly looks at the evidence – ie all we currently know about the laws of nature – must come to the same conclusions. The main obstacle in conveying this message is that most people without training in particle physics don’t understand effective field theory, and consequently don’t see what this implies for the emergence of higher level laws. Sean does a great job overcoming this obstacle.

I wish I could make myself believe that after the publication of Sean’s book I’ll never again have to endure someone insisting there must be something about their experience that can’t be described by a handful of elementary particles. But I’m not very good at making myself believe in exceedingly unlikely scenarios, whether that’s the existence of an omniscient god or the ability of humans to agree on how unlikely this existence is. At the very least however, The Big Picture should make clear that physicists aren’t just arrogant when they say their work reveals insights that reach far beyond the boundaries of their discipline. Physics indeed has an exceptional status among the sciences.

[Disclaimer: Free review copy.]

Book review: “From the Great Wall to the Great Collider” by Nadis and Yau

From the Great Wall to the Great Collider: China and the Quest to Uncover the Inner Workings of the Universe
By Steve Nadis and Shing-Tung Yau
International Press of Boston (October 23, 2015)

Did you know that particle physicists like the Chinese government’s interest in building the next larger particle collider? If not, then this neat little book about the current plans for the Great Collider, aka “Nimatron,” is just for you.

Nadis and Yau begin their book laying out the need for a larger collider, followed by a brief history of accelerator physics that emphasizes the contribution of Chinese researchers. Then come two chapters about the hunt for the Higgs boson, the LHC’s success, and a brief survey of beyond the standard model physics that focuses on supersymmetry and extra dimensions. The reader then learns about other large-scale physics experiments that China has run or is running, and about the currently discussed options for the next larger particle accelerator. Nadis and Yau don’t waste time discussing details of all accelerators that are presently considered, but get quickly to the point of laying out the benefits of a circular 50 or even 100 TeV collider in China.

And the benefits are manifold. The favored location for the gigantic project is Qinghuangdao, which is “an attractive destination that might appeal to foreign scientists” because, among other things, “its many beaches [are] ranked among the country’s finest,” “the countryside is home to some of China’s leading vineyards” and even the air quality is “quite good” at least “compared to Beijing.” Book me in.

The authors make a good case that both the world and China only have to gain from the giant collider project. China because “one result would likely be an enhancement of national prestige, with the country becoming a leader in the field of high-energy physics and perhaps eventually becoming the world center for such research. Improved international relations may be the most important consequence of all.” And the rest of the world benefits because, besides preventing thousands of particle physicists from boredom, “civil engineering costs are low in the country – much cheaper than those in many Western countries.”

The book is skillfully written with scientific explanations that are detailed, yet not overly technical, and much space is given to researchers in the field. Nadis and Yau quote whoever might help getting their message across: David Gross, Lisa Randall, Frank Wilczek, Don Lincoln, Don Hopper, Joseph Lykken, Nima Arkani-Hamed, Nathan Seiberg, Martinus Veltman, Steven Weinberg, Gordon Kane, John Ellis – everybody gets a say.

My favorite quote is maybe that by Henry Tye, who argues that the project is a good investment because “the worldwide impact of a collider is much bigger than if the money were put into some other area of science,” since “even if China were to spend more than the United States in some field of science and engineering other than high-energy physics, US professors would still do their research in the US.” This quote sums up the authors’ investigation of whether such a major financial commitment might maybe have a larger payoff were it invested into any other research area.

Don’t get me wrong there, if the Chinese want to build a collider, I think that’s totally great and an awesome contribution to knowledge discovery and the good of humanity, the forgiveness of sins, the resurrection of the body, and the life everlasting, amen. But there’s a real discussion here to be had whether building the next bigger ring-thing is where the money should flow or if not putting a radio telescope on the moon or a gravitational wave interferometer in space would bring more bang for the Yuan. Unfortunately, you’re not going to find that discussion in Nadis and Yau’s book.

Aside: The print has smear-stripes.Yes, that puts me in a bad mood.

In summary, this book will come in very handy next time you have to convince a Chinese government official to spend a lot of money on bringing protons up to speed.

[Disclaimer: Free review copy.]

Book review: “Beyond the Galaxy” by Ethan Siegel

Beyond the Galaxy: How Humanity Looked Beyond Our Milky Way and Discovered the Entire Universe
By Ethan Siegel
World Scientific Publishing Co (December 9, 2015)

Ethan Siegel’s book is an introduction to modern cosmology that delivers all the facts without the equations. Like Ethan’s collection “Starts With a Bang,” it is well-explained and accessible for the reader without any prior knowledge in physics. But this access doesn’t come without effort. This isn’t a book for the strolling pedestrian who likes being dazzled by the wonders of modern science, it’s a book for the inquirer who wants to turn around everything behind the display-window of science news.

“Beyond the Galaxy” tells the history of the universe and the basics of the relevant measurement techniques. It explains the big bang theory and inflation, the formation of matter in the early universe, dark matter, dark energy, and briefly mentions the multiverse. Siegel elaborates on the cosmic microwave background and what we have learned from it, baryon acoustic oscillations, and supernovae redshift. For the most part, the book sticks closely with well-established physics and stays away from speculations, except when it comes to the possible explanations for dark matter and dark energy.

Having said what the book contains, let me spell out what it doesn’t contain. This is not a book about astrophysics. You will not find elaborate discussions about all the known astrophysical objects and their physical process. This is also not a book about particle physics. Ethan does not include dark matter direct detection experiments, and while some particle physics necessarily enters the discussion of matter formation, he sticks with the very essentials. It is also not a history book. Though Ethan does a good job giving the reader a sense of the timeline of discoveries, this is clearly not the focus of his interest.

Ethan might not be the most lyrical writer ever, but his explanations are infallibly clear and comprehensible. The book is accompanied by numerous illustrations that are mostly helpful, though some of them contain more information than is explained in the text.

In short, Ethan’s book is the missing link between cosmology textbooks and popular science articles. It will ease your transition if you are attempting one, or, if that is not your intention, it will serve to tie together the patchy knowledge that news articles often leave us with. It is the ideal starting point if you want to get serious about digging into cosmology, or if you are just dissatisfied by the vagueness of much contemporary science writing. It is, in one word, a sciency book.

[Disclaimer: Free review copy, plus I write for Ethan once per month.]

Book review: “Seven brief lessons on physics” by Carlo Rovelli

Seven Brief Lessons on Physics
By Carlo Rovelli
Allen Lane (September 24, 2015)

Carlo Rovelli’s book is a collection of essays about the fundamental laws of physics as we presently know them, and the road that lies ahead. General Relativity, quantum mechanics, particle physics, cosmology, quantum gravity, the arrow of time, and consciousness, are the topics that he touches upon in this slim, pocket-sized, 79 pages collection.

Rovelli is one of the founders of the research program of Loop Quantum Gravity, an approach to understanding the quantum nature of space and time. His “Seven brief lessons on physics” are short on scientific detail, but excel in capturing the fascination of the subject and its relevance to understand our universe, our existence, and ourselves. In laying out the big questions driving physicists’ quest for a better understanding of nature Rovelli makes it clear how the, often abstract, contemporary research is intimately connected with the ancient desire to find our place in this world.

As a scientist, I would like to complain about numerous slight inaccuracies, but I forgive them since they are admittedly not essential to the message Rovelli is conveying, that is the value of knowledge for the sake of knowledge itself. The book is more a work of art and philosophy than of science, it’s the work of a public intellectual reaching out to the masses. I applaud Carlo for not dumbing down his writing, for not being afraid of using multi-syllable words and constructing nested sentences; it’s a pleasure to read. He seems to spend too much time on the beach playing with snail-shells though.

I might have recommended the book as a Christmas present for your relatives who never quite seem to understand why anyone would spend their life pondering the arrow of time, but I was too busy pondering the arrow of time to finish the book before Christmas.

I would recommend this book to anyone who wants to understand how fundamental questions in physics tie together with the mystery of our own existence, or maybe just wants a reminder of what got them into this field decades ago.

[Disclaimer: I got the book as gift from the author.]

Book review: Spooky Action at a Distance by George Musser

Spooky Action at a Distance: The Phenomenon That Reimagines Space and Time--and What It Means for Black Holes, the Big Bang, and Theories of Everything
By George Musser
Scientific American, To be released November 3, 2015

“Spooky Action at a Distance” explores the question Why aren’t you here? And if you aren’t here, what is it that prevents you from being here? Trying to answer this simple-sounding question leads you down a rabbit hole where you have to discuss the nature of space and time with many-world proponents and philosophers. In his book, George reports back what he’s found down in the rabbit hole.

Locality and non-locality are topics as confusing as controversial, both in- and outside the community, and George’s book is a great introduction to an intriguing development in contemporary physics. It’s a courageous book. I can only imagine how much headache writing it must have been, after I once organized a workshop on nonlocality and realized that no two people could agree on what they even meant with the word.

George is a very gifted writer. He gets across the most relevant concepts the reader needs to know on a nontechnical level with a light and unobtrusive humor. The historical background is nicely woven together with the narrative, and the reader gets to meet many researchers in the field, Steve Giddings, Fotini Markopoulou, and Nima Arkani-Hamed, to only mention a few.

In his book, George lays out how the attitude of scientists towards nonlocality has gone from acceptance to rejection and makes a case that now the pendulum is swinging back to acceptance again. I think he is right that this is the current trend (thus the workshop).

I found the book somewhat challenging to read because I was constantly trying to translate George’s metaphors back into equations and I didn’t always succeed. But then that’s a general problem I have with popular science books and I can’t blame George for this. I have another complaint though, which his that George covers a lot of different research in rapid succession without adding qualifiers about these research programs’ shortcomings. There’s quantum graphity and string theory and black holes in AdS and causal sets and then there’s many worlds. The reader might be left with the mistaken impression that these topics are somehow all related with each other.

Spooky Action at a Distance starts out as an Ode to Steve Giddings and ends as a Symphony for Arkani-Hamed. For my taste it’s a little too heavy on person-stories, but then that seems to be the style of science writing today. In summary, I can only say it’s a great book, so go buy it, you won’t regret it.

[Disclaimers: Free review copy; I know the author.]

Fade-out ramble: You shouldn’t judge a book by its subtitle, really, but whoever is responsible for this title-inflation, please make it stop. What’s next? Print the whole damn book on the cover?

Book Review: “A Beautiful Question” by Frank Wilczek

A Beautiful Question: Finding Nature's Deep Design
By Frank Wilczek
Penguin Press (July 14, 2015)

My four year old daughter recently discovered that equilateral triangles combine to larger equilateral triangles. When I caught a distracted glimpse of her artwork, I thought she had drawn the baryon decuplet, an often used diagram to depict relations between particles composed of three quarks.

The baryon decuplet doesn’t come easy to us, but the beauty of symmetry does, and how amazing that physicists have found it tightly woven into the fabric of nature itself: Both the standard model of particle physics and General Relativity, our currently most fundamental theories, are in essence mathematically precise implementations of symmetry requirements. But next to being instrumental for the accurate description of nature, the appeal of symmetries is a human universal that resonates in art and design throughout cultures. For the physicist, it is impossible not to note the link, not to see the equations behind the art. It may be a curse or it may be a blessing.

For Frank Wilczek it clearly is a blessing. In his most recent book “A Beautiful Question,” he tells the success of symmetries in physics, and goes on to answer his question whether “the world embodies beautiful ideas” with a clear “Yes.”

Lara’s decuplet

Wilczek starts from the discovery of basic mathematical relationships like Pythagoras’ theorem (not shying away from explaining how to prove it!) and proceeds through the history of physics along selected milestones such as musical harmonies, the nature of light and the basics of optics, Newtonian gravity and its extension to General Relativity, quantum mechanics, and ultimately the standard model of particle physics. He briefly touches on condensed matter physics, graphene in particular, and has an interesting digression about the human eye’s limited ability to decode visual information (yes, the shrimp again).

In the last chapters of the book, Wilczek goes into quite some detail about the particle content of the standard model, and in just which way it seems to be not as beautiful as one may have hoped. He introduces the reader to extended theories, grand unification and supersymmetry, invented to remedy the supposed shortcomings of the standard model. The reader who is not familiar with the quantum numbers used to classify elementary particles will likely find this chapter somewhat demanding. But whether or not one makes the effort to follow the details, Wilczek’s gets his message across clearly: Striving for beauty in natural law has been a useful guide, and he expects it to remain one, even though he is careful to note that relying on beauty has on various occasions lead to plainly wrong theories, such as the attempt to explain planetary orbits with the Platonic solids, or to the idea to develop a theory of atoms based on the mathematics of knots.

“A Beautiful Question” is a skillfully written reflection, or “meditation” as Wilczek puts it. It is well structured and accompanied by many figures, including two inserts with color prints. The book also contains an extensive glossary, recommendations for further reading, and a timeline of the discoveries mentioned in the text.

My husband’s decuplet.

The content of the book is unique in the genre. David Goldberg’s book “The Universe in the Rearview Mirror: How Hidden Symmetries Shape Reality,” for example, also discusses the role of symmetries in fundamental physics, but Wilzcek gives more space to the connection between aesthetics in art and science. “A Beautiful Question” picks up and expands on the theme of Steven Weinberg’s 1992 book “Dreams of a Final Theory” that also expounded the relevance of beauty in the development of physical theories. More than 20 years have passed, but the dream is still as elusive today as it was back then.

For all his elaboration on the beauty of symmetry though, Wilczek’s book falls short of spelling out the main conundrum physicists face today: We have no reason to be confident that the laws of nature which we have yet to discover will conform to the human sense of beauty. Neither does he spend many words on aspects of beauty beyond symmetry; Wilczek only briefly touches on fractals, and never goes into the rich appeal of chaos and complexity.

My mother used to say that “symmetry is the art of the dumb,” which is maybe a somewhat too harsh criticism on the standard model, but seeing that reliance on beauty has not helped us within the last 20 years, maybe it is time to consider that the beauty of the answers might not reveal itself as effortlessly as does the tiling of the plane to a 4 year old. Maybe the inevitable subjectivity in our sense of aesthetic appeal that has served us well so far is about to turn from a blessing to a curse, misleading us as to where the answers lie.

Wilczek’s book contains something for every reader, whether that is the physicist interested to learn how a Nobel Prize winner thinks of the connection between ideas and reality, or the layman wanting to know more about the structure of fundamental law. “A Beautiful Question” reminds us of the many ways that science connects to the arts, and invites us to marvel at the success our species has had in unraveling the mysteries of nature.

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[An edited version of this review appeared in the October issue of Physics Today.]

Book review: “Eureka” by Chad Orzel.

Eureka: Discovering Your Inner Scientist
By Chad Orzel
Basic Books (December 9, 2014)

It’s a good book, really. The problem isn’t the book, the problem is me.

Chad Orzel’s new book “Eureka” lays out how the scientific enterprise reflects in every-day activities. In four parts, “Look, Think, Test, Tell,” Chad connects examples from sports, cooking, collecting, crossword puzzles, mystery novels, and more, to the methodology used in scientific discovery. Along the way, he covers a lot of ground in astrophysics, cosmology, geology, and atomic physics. And the extinction of the dinosaurs.

It’s a well-written book, with relevant but not excessive references and footnotes; the scientific explanations are accurate yet non-technical; the anecdotes from the history of science and contemporary academia are nicely woven together with the books theme, that every one of us has an “inner scientist” who is waiting to be discovered.

To my big relief in this recent book Chad doesn’t talk to his dog. Because I’m really not a dog person. I’m the kind of person who feeds the neighbor’s cat. Sometimes. I’m also the kind of person who likes baking, running, house music, and doesn’t watch TV. I order frozen food and get it delivered to the door. Chad cooks, believes baking is black magic, plays basketball, likes rock music, and his writing draws a lot on contemporary US TV shows or movies. He might be a good science popularizer, but his sports popularization is miserable. It doesn’t seem to have occurred to him that somebody could read his book who, like me, doesn’t know anything about baseball, or bridge, or basketball, and therefore much of his explanations are entirely lost on me.

I don’t think I’ve ever read a book that made me feel so distinctly that I’m not the intended audience. Of course the whole idea of “Eureka” is totally backwards for me. You don’t have to convince me I’m capable of scientific reasoning. I have even proved capable of convincing others I’m capable of scientific reasoning. Sometimes. But I do not have the slightest idea why somebody would want to spend hours trying to throw a ball into a basket, or, even more bizarre, watch other people trying to throw balls into baskets. So some stretches of the book stretched indeed. Which is why it’s taken me so long to get through with it, since I had an advance proof more than a year ago.

Besides this, I have a general issue with the well-meant message that we were born to think scientifically, as I elaborated on in this recent post. Chad’s argument is that every one of us brings the curiosity and skills to be a scientist, and that we use many of these skills intuitively. I agree on this. Sometimes. I wish though that he had spent a few more words pointing out that being a scientist is a profession after all, and one that requires adequate education for a reason. While we do some things right intuitively, intuition can also mislead us. I understand that Chad addresses an existing cultural misconception, which is that science is only for a gifted few rather than a general way to understand the world. However, I’d rather not swap this misconception for another misconception, which is that scientific understanding comes with little guidance and effort.

In summary, it’s a great book to give to someone who is interested in sports but not in science, to help them discover their inner scientist. Chad does an excellent job pointing out how much scientific thought there is in daily life, and he gets across a lot of physics along with that. He tells the reader that approaching problems scientifically is not just helpful for researchers, but for every one to understand the world. Sometimes. Now somebody please explain me the infield fly rule.

Book Review: “String Theory and the Scientific Method” by Richard Dawid

String Theory and the Scientific Method
By Richard Dawid
Cambridge University Press (2013)

“String Theory and the Scientific Method” is a very interesting and timely book by a philosopher trying to make sense out of trends in contemporary theoretical physics. Dawid has collected arguments that physicists have raised to demonstrate the promise of their theories, arguments that however are not supported by the scientific method as it is currently understood. He focuses on string theory, but some of his observations are more general than this.

There is for example that physicists rely on mathematical consistency as a guide, even though this is clearly not an experimental assessment. A theory that isn’t mathematically consistent in some regime where we do not have observations yet isn’t considered fundamentally valid. I have to admit it wouldn’t even have occurred to me to call this a “non-empirical assessment,” because our use of mathematics is clearly based on the observation that it works very well to describe nature.

The three arguments that Dawid has collected which are commonly raised by string theorists to support their belief that string theory is a promising theory of everything are:

1. Meta-inductive inference: The trust in a theory is higher if its development is based on extending existing successful research programs.
2. No-alternatives argument: The more time passes in which we fail to find a theory as successful as string theory in combining quantum field theory with general relativity the more likely it is that the one theory we have found is unique and correct.
3. Argument of unexpected explanatory coherence: A finding is perceived more important if it wasn’t expected.

Dawid then argues basically that since a lot of physicists are de facto not relying on the scientific method any more maybe philosophers should face reality and come up with a better explanation that would alter the scientific method so that according to the new method the above arguments were scientific.

In the introduction Dawid writes explicitly that he only studies the philosophical aspects of the development and not the sociological ones. My main problem with the book is that I don’t think one can separate these two aspects clearly. Look at the arguments that he raises: The No Alternatives Argument and the Unexpected Explanatory Coherence are explicitly sociological. They are 1.) based on the observation that there exists a large research area which attracts much funding and many young people and 2.) that physicists trust their colleagues’ conclusions better if it wasn’t the conclusion they were looking for. How can you analyze the relevance of these arguments without taking into account sociological (and economic) considerations?

The other problem with Dawid’s argument is that he confuses the Scientific Method with the rest of the scientific process that happens in the communities. Science basically operates as a self-organized adaptive system, that is in the same class of systems as natural selection. For such systems to be able to self-optimize something – in the case of science the use of theories for the descriptions of nature – they must have a mechanism of variation and a mechanism for assessment of the variation followed by a feedback. In the case of natural selection the variation is genetic mixing and mutation, the assessment is whether the result survives, the feedback is another reproduction. In science the variation is a new theory and the assessment is whether it agrees with experimental test. The feedback is the revision or trashcanning of the theory. This assessment whether a theory describes observation is the defining part of science – you can’t change this assessment without changing what science does because it determines what we optimize for.

The assessments that Dawid, correctly, observes are a pre-selection that is meant to assure we spend time only on those theories (gene combinations) that are promising. To make a crude analogy, we clearly do some pre-selection in our choice of partners that determines which genetic combinations are ever put to test. These might be good choices or they might be bad choices and as long as their success hasn’t also been put to test, we have to be very careful whether we rely on them. It’s the same with the assessments that Dawid observes. Absent experimental test, we don’t know if using these arguments does us any good. In fact I would argue that if one takes into account sociological dynamics one presently has a lot of reasons to not trust researchers to be objective and unbiased which sheds much doubt on the use of these arguments.

Be that as it may, Dawid’s book has been very useful for me to clarify my thoughts about exactly what is going on in the community. I think his observations are largely correct, just that he draws the wrong conclusion. We clearly don’t need to update the scientific method, we need to apply it better, and we need to apply it in particular to better understand the process of knowledge discovery.

I might never again agree with David Gross on anything, but I do agree on his “pre-publication praise” on the cover. The book is very recommendable reading both for physicists and philosophers.

I wasn’t able to summarize the arguments in the book without drawing a lot of sketches, so I made a 15 mins slideshow with my summary and comments on the book. If you have the patience, enjoy :)

Book review: "Cracking the Particle Code of the Universe" by John Moffat

Cracking the Particle Code of the Universe: the Hunt for the Higgs Boson
By John W Moffat
Oxford University Press (2014)

John Moffat’s new book covers the history of the Standard Model of particle physics from its beginnings to the recent discovery of the Higgs boson – or, as Moffat cautiously calls it, the new particle most physicists believe is the Standard Model Higgs. But Cracking the Particle Code of the Universe isn’t just any book about the Standard Model: it’s about the model as seen through the eyes of an insider, one who has witnessed many fads and statistical fluctuations come and go. As an emeritus professor at the University of Toronto, Canada and a senior researcher at the nearby Perimeter Institute, Moffat has the credentials to do more than just explain the theory and the experiments that back it up: he also offers his own opinion on the interpretation of the data, the status of the theories and the community’s reaction to the discovery of the Higgs.

The first half of the book is mainly dedicated to introducing the reader to the ingredients of the Standard Model, the particles and their properties, the relevance of gauge symmetries, symmetry breaking, and the workings of particle accelerators. Moffat also explains some proposed extensions and alternatives to the Standard Model, such as technicolor, supersymmetry, preons, additional dimensions and composite Higgs models as well as models based on his own work. In each case he lays out the experimental situation and the technical aspects that speak for and against these models.

In the second half of the book, Moffat recalls how the discovery unfolded at the LHC and comments on the data that the collisions yielded. He reports from several conferences he attended, or papers and lectures that appeared online, and summarizes how the experimental analysis proceeded and how it was interpreted. In this, he includes his own judgment and relates discussions with theorists and experimentalists. We meet many prominent people in particle physics, including Guido Altarelli, Jim Hartle and Stephen Hawking, to mention just a few. Moffat repeatedly calls for a cautious approach to claims that the Standard Model Higgs has indeed been discovered, and points out that not all necessary characteristics have been found. He finds that the experimentalists are careful with their claims, but that the theoreticians jump to conclusions.

The book covers the situation up to March 2013, so of course it is already somewhat outdated; the ATLAS collaboration’s evidence for the spin-0 nature of the Higgs boson was only published in June 2013, for example. But this does not matter all that much because the book will give the dedicated reader the necessary background to follow and understand the relevance of new data.

Moffat’s writing sometimes gets quite technical, albeit without recourse to equations, and I doubt that readers will fully understand his elaborations without at least some knowledge of quantum field theory. He introduces the main concepts he needs for his explanations, but he does so very briefly; for example, his book features the briefest explanation of gauge invariance I have ever come across, and many important concepts, such as cross-sections or the relation between the masses of force-carriers and the range of the force, are only explained in footnotes. The glossary can be used for orientation, but even so, the book will seem very demanding for readers who encounter the technical terms for the first time. However, even if they are not able to follow each argument in detail, they should still understand the main issues and the conclusions that Moffat draws.

Towards the end of the book, Moffat discusses several shortcomings of the Standard Model, including the Higgs mass hierarchy problem, the gauge hierarchy problem, and the unexplained values of particle masses. He also briefly mentions the cosmological constant problem, as it is related to questions about the nature of the vacuum in quantum field theory, but on the whole he stands clear from discussing cosmology. He does, however, comment on the anthropic principle and the multiverse and does not hesitate to express his dismay about the idea.

While Moffat gives some space to discussing his own contributions to the field, he does not promote his point of view as the only reasonable one. Rather, he makes a point of emphasizing the necessity of investigating alternative models. The measured mass of the particle-that-may-be-the-Higgs is, he notes, larger than expected, and this makes it even more pressing to find models better equipped to address the problems with “naturalness” in the Standard Model.

I have met Moffat on various occasions and I have found him to be not only a great physicist and an insightful thinker, but also one who is typically more up-to-date than many of his younger colleagues. As the book also reflects, he closely follows the online presentations and discussions of particle physics and particle physicists, and is conscious of the social problems and cognitive biases that media hype can produce. In his book, Moffat especially criticizes bloggers for spreading premature conclusions.

Moffat’s recollections also document that science is a community enterprise and that we sometimes forget to pay proper attention to the human element in our data interpretation. We all like to be confirmed in our beliefs, but as my physics teacher liked to say “belief belongs into the church.” I find it astonishing that many theoretical physicists these days publicly express their conviction that a popular theory “must be” right even when still unconfirmed by data – and that this has become accepted behavior for scientists. A theoretician who works on alternative models today is seen too easily as an outsider (a non-believer), and it takes much courage, persistence, and stable funding sources to persevere outside mainstream, like Moffat has done for decade and still does. This is an unfortunate trend that many in the community do not seem to be aware of, or do not see why it is of concern, and it is good that Moffat in his book touches on this point.

In summary, Moffat’s new book is a well-done and well-written survey of the history, achievements, and shortcomings of the Standard Model of particle physics. It will equip the reader with all the necessary knowledge to put into context the coming headlines about new discoveries at the LHC and future colliders.

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This review first appeared in Physics World on Dec 4th under the title "A strong model, with flaws".

Book review: "The Edge of the Sky" by Roberto Trotta

The Edge of the Sky: All You Need to Know about the All-There-Is
Roberto Trotta
Basic Books (9. Oktober 2014)

It's two days before Christmas and you need a last-minute gift for that third-degree-uncle, heretofore completely unknown to you, who just announced a drop-in for the holidays? I know just the right thing for you: "The Edge of the Sky" by Roberto Trotta, which I found as free review copy in my mailbox one morning.

According to the back flap, Roberto Trotta is a lecturer in astrophysics at Imperial College. He has very blue eyes and very white teeth, but I have more twitter followers, so I win. Roberto set out to explain modern cosmology with only the thousand most used words of the English language. Unfortunately, neither "cosmology" nor "thousand" belongs to these words, and certainly not "heretofore" which might or might not mean what I think it means.

The result is a nice little booklet telling a story about "big-seers" (telescopes) and "star-crowds" (galaxies) and the "early push" (inflation) with a couple of drawings for illustration. It's pretty and kinda artsy which probably isn't a word at all. The book is also as useless as that price-winning designer chair in which one can't sit, but better than the chair because it's very slim and will not take up much space, or money. It's just the right thing to give to your uncle who will probably not read it and so he'll never find out that you think he's too dumb to know the word "particle". It is, in summary, the perfect re-gift, so go and stuff it into somebody's under-shoe-clothes - how am I doing?

Is there a smallest length?

Good ideas start with a question. Great ideas start with a question that comes back to you. One such question that has haunted scientists and philosophers since thousands of years is whether there is a smallest unit of length, a shortest distance below which we cannot resolve structures. Can we look closer and always closer into space, time, and matter? Or is there a limit, and if so, what is the limit?

I picture our foreign ancestors sitting in their cave watching the world in amazement, wondering what the stones, the trees and they themselves are made of – and starving to death. Luckily, those smart enough to hunt down the occasional bear eventually gave rise to human civilization sheltered enough from the harshness of life to let the survivors get back to watching and wondering what we are made of. Science and philosophy in earnest is only a few thousand years old, but the question whether there is smallest unit has always been a driving force in our studies of the natural world.

The old Greeks invented atomism, the idea that there is an ultimate and smallest element of matter that everything is made of. Zeno’s famous paradoxa sought to shed light on the possibility of infinite divisibility. The question came back with the advent of quantum mechanics, with Heisenberg’s uncertainty principle that fundamentally limits the precision by which we can measure. It became only more pressing with the divergences in quantum field theory that are due to the inclusion of infinitely short distances.

It was in fact Heisenberg who first suggested that divergences in quantum field theory might be cured by the existence of a fundamentally minimal length, and he introduced it by making position operators non-commuting among themselves. Like the non-commutativity of momentum and position operators leads to an uncertainty principle, so does the non-commutativity of position operators limits how well distances can be measured.

Heisenberg’s main worry, which the minimal length was supposed to deal with, was the non-renormalizability of Fermi’s theory of beta-decay. This theory however turned out to be only an approximation to the renormalizable electro-weak interaction, so he had to worry no more. Heisenberg’s idea was forgotten for some decades, then picked up again and eventually grew into the area of non-commutative geometries. Meanwhile, the problem of quantizing gravity appeared on stage and with it, again, non-renormalizability.

In the mid 1960s Mead  reinvestigated Heisenberg’s microscope, the argument that lead to the uncertainty principle, with (unquantized) gravity taken into account. He showed that gravity amplifies the uncertainty so that it becomes impossible to measure distances below the Planck length, about 10^-33 cm. Mead’s argument was forgotten, then rediscovered in the 1990s by string theorists who had noticed using strings to prevent divergences by avoiding point-interactions also implies a finite resolution, if in a technically somewhat different way than Mead’s.

Since then the idea that the Planck length may be a fundamental length beyond which there is nothing new to find, ever, appeared in other approaches towards quantum gravity, such as Loop Quantum Gravity or Asymptotically Safe Gravity. It has also been studied as an effective theory by modifying quantum field theory to include a minimal length from scratch, and often runs under the name “generalized uncertainty”.

One of the main difficulties with these theories is that a minimal length, if interpreted as the length of a ruler, is not invariant under Lorentz-transformations due to length contraction. This problem is easy to overcome in momentum space, where it is a maximal energy that has to be made Lorentz-invariant, because momentum space is not translationally invariant. In position space one either has to break Lorentz-invariance or deform it and give up locality, which has observable consequences, and not always desired ones. Personally, I think it is a mistake to interpret the minimal length as the length of a ruler (a component of a Lorentz-vector), and it should instead be interpreted as a Lorentz-invariant scalar to begin with, but opinions on that matter differ.

The science and history of the minimal length has now been covered in a recent book by Amit Hagar:

Discrete or Continuous? The Quest for Fundamental Length inModern Physics
Amit Hagar
Cambridge University Press (2014)

Amit is a philosopher but he certainly knows his math and physics. Indeed, I suspect the book would be quite hard to understand for a reader without at least some background knowledge in math and physics. Amit has made a considerable effort to address the topic of a fundamental length from as many perspectives as possible, and he covers a lot of scientific history and philosophical considerations that I had not previously been aware of. The book is also noteworthy for including a chapter on quantum gravity phenomenology.

My only complaint about the book is its title because the question of discrete vs continuous is not the same as the question of finite vs infinite resolution. One can have a continuous structure and yet be unable to resolve it beyond some limit (this is the case when the limit makes itself noticeable as a blur rather than a discretization). On the other hand, one can have a discrete structure that does not prevent arbitrarily sharp resolution (which can happen when localization on a single base-point of the discrete structure is possible).

(Amit’s book is admittedly quite pricey, so let me add that he said should sales numbers reach 500 Cambridge University Press will put a considerably less expensive paperback version on offer. So tell your library to get a copy and let’s hope we’ll make it to 500 so it becomes affordable for more of the interested readers.)

Every once in a while I think that there maybe is no fundamentally smallest unit of length, that all these arguments for its existence are wrong. I like to think that we can look infinitely close into structures and will never find a final theory, turtles upon turtles, or that structures are ultimately self-similar and repeat. Alas, it is hard to make sense of the romantic idea of universes in universes in universes mathematically, not that I didn’t try, and so the minimal length keeps coming back to me.

Many if not most endeavors to find observational evidence for quantum gravity today look for manifestations of a minimal length in one way or the other, such as modifications of the dispersion relation, modifications of the commutation-relations, or Bekenstein’s tabletop search for quantum gravity. The properties of these theories are today a very active research area. We’ve come a long way, but we’re still out to answer the same questions that people asked themselves thousands of years ago.

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This post first appeared on Starts With a Bang with the title "The Smallest Possible Scale in the Universe" on August 12, 2014.