Sunday, July 08, 2007

The LHC Theory Initiative

Want proof that the grass is always greener on the other side? I just read this article

Refilling the Physicist Pool

about the LHC theory initiative:

"We are behind the Europeans, and we believe very strongly that we shouldn't just leave this work to the Europeans," Baur said in a UB statement. [...]
Funding in the US for particle physics as a whole and theoretical particle physics in particular has declined significantly over the past 15 years, Baur said. In addition, physics departments in US universities tend to hire faculty members who develop innovative ideas, whereas in Europe, the physics culture puts equal emphasis on novel research and solid calculations that help advance the field as a whole. But with the Large Hadron Collider -- the world's largest particle accelerator -- coming online in the next year or sooner, Baur said, the US cannot afford to fall behind."

It's interesting that in the US ideas are 'innovative' whereas in Europe they are 'novel' (especially since both refers to a field that is several decades old, and hasn't seen very much novelty lately). Admittedly, I find the perspective of a 'physics culture' that produces 'solid' Next-to-next-to-next-to-next-to leading order calculations somewhat depressing.

For German counterpart, see also the Terrascale Alliance.

22 comments:

QUASAR9 said...

Hi Bee, the world is changing every day before our eyes
Not just the Internet & broadband, evermore powerful laptops, mobile phones and video phones, and a thousand and one extras as standard in your average car ftom porsche ignition, to tinted electric windows, to self-cleaning halogen headlamps, to bumpers with memory - and tyre technology to the nth degree.

Some people thought they'd killed Grand Prix when they put a limit on the size of the engine, yet innovation has continued ... and new developments are added every day to production cars.

What would you want to see change.
And when you discover or reveal it, will it not become old news, even before it hits print or the press.

So, Bee what do you want to SEE in Particle Physics, or rather what would you like to SEE ... I don't mean overnight - I mean which direction do you think it should take. Have you thought what you'd like to spend the next twenty or thirty years working on - that will fulfill your personal goals, and deliver anything significantly novel or NEW?

This could create an ever better (and interesting) series of posts, than your previous posts debating funding

Bee said...

Hi Quasar:

The kind of change that you refer to is technological refinement. It relies on improving existing knowledge, making it smaller, more intelligent, but also more complex and prone to failure. Without 'novelty' (or innovation?) this is not a sustainable progress, but will sooner or later stagnate. A major issue here being available energy resources.

Regarding what I would like to see, well, if you ask me, there are sufficiently many particle physicists out there. Maybe they are not too well distributed over the globe, I don't know. Yes, I think they do an excellent job (well. most of them do), and it's an important field. But I am not presently too concerned about their future. I honestly don't understand the above arguments based on competition (competitiveness initiative US version, EU version). It's like saying the Italian on the other side of the street has larger Pizzas, so we'll need to have even larger ones! But do we really want ever larger Pizzas?

What I would like to see is more courage. Courage to ask and to attack the questions that can get us somewhere. There are thousands of people working with quantum field theories. Yet, none of them can explain why we quantize, or why we do it the way we do. There are hundreds of people working on extra dimensions, yet none of them can explain why we have three large spatial dimensions. There are hundreds of people using Wick rotations, or working in Euclidean settings, yet none of them can explain why we have a time, or why it has an 'arrow'. There are thousands of people working on quantizing gravity, yet none of them was able to convince me that we have to quantize it at all (several tried, but I don't think the arguments are convincing). Nobody knows what dark matter is, or dark energy. Nobody knows how to avoid the formation of singularities in GR. Nobody can explain the parameters in the standard model. Recently people have argued there might indeed be a whole landscape of possible standard models... (See also my top ten questions in theoretical physics). THAT is what we need a theory initiative for.

Best,

B.

QUASAR9 said...

I agree Bee,
"What I would like to see is more courage. Courage to ask and to attack the questions that can get us somewhere."

Like music, classical music tries to perpetuate classical mucic, pop music tries to perpetuate pop, and all other music is a variation on the theme, different instruments, different tone, but still the same notes and trying to create a new melody or the next catchy tune.

As for the analogy of the pizza, it's a little unfair - we are limited by the budget and size of the project, whether it be a collider or a dam. Whether it be a Nuclear Reactor or Cold Fusion.

Sure sometimes we build pyramids or skycrapers just to top the last one...

Half the picture is finding neutrinos and new particles and theorising about strings and extra dimensions ... the other half is knowing how to use or apply them.
Certain in molecular biology and medicine, there is much yet to be revealed - and more important unlocked.

PS - "The kind of change that you refer to is technological refinement. It relies on improving existing knowledge, making it smaller, more intelligent, but also more complex and prone to failure. Without 'novelty' (or innovation?) this is not a sustainable progress, but will sooner or later stagnate. A major issue here being available energy resources."
Bee, that is your personal opinion, the next generation with their enthusiasm always bring new advances in technology to cars and transport, fuels and energy ...
the electric (Tesla & lotus) car is already here, a new generation of jet engines anfd get fuel is on its way, and to you domestic appliances and gadgets may be boring, but the Japs don't stop dreaming up new ones.

PPS - I challenge you to have a weekly post which will provoke a reaction, giving the answers to the very questions you pose or raising more questions.

Here's the first one:
Why do you want to avoid forming singularities in GR?

As for Time and the arrow of Time, it will take several (million) posts to chew on that - lol!

Moshe said...

Bee said: There are thousands of people working on quantizing gravity, yet none of them was able to convince me that we have to quantize it at all...


It depends what you mean by "quantizing gravity". Most string theorists would mean "find a quantum mechanical model which includes general relativity at low energies". This is slightly less general than "find mathematical model which reduces to GR and quantum mechanics at low energies", a statement which is hard to argue with...modifications to QM at high energies is a logical possibility, just hard to make concrete.

The more naive version is quantizing GR directly: take the metric and do a path integral or promote it to an operator or something. This is a route most of us believe leads nowhere, so in that sense indeed we don't need to "quantize gravity".

Bee said...

Dear Quasar:

Yes, that is my personal opinion. I don't consider faster cars to be progress.

I challenge you to have a weekly post which will provoke a reaction, giving the answers to the very questions you pose or raising more questions.

My research will not go over this blog. If I come to conclusions, I will write a paper. I can't invest more time into this blog than I currently do without taking it from my research, and I am not willing to do so because it's not an appropriate replacement. I enjoy writing this blog, but there are limits to what I think blogging can achieve.

Dear Moshe:

statement which is hard to argue with...modifications to QM at high energies is a logical possibility, just hard to make concrete.

I agree and this is exactly the reason why I am not writing about it: I don't think if there is a fundamental theory, it is quantized at all, but this is not a conrete argument.

Best,

B.

Uncle Al said...

Professional management is about finding maxima and minima on an apparently flat response hypersurface. Discovery and innovation are about finding better hypersurfaces.

The surest way to lose everything is to make every bet a sure bet. Reverend William Oughtred innvented the slide rule in 1622. How many HP-35s did Pickett or Keuffel & Esser management purchase 350 years later?

HP Marketing expected to sell 50,000 unitss. General Electric bought 20,000 HP-35s in a single order. 300,000 were sold by 1975.

The future is meant to be dangerous.

Uncle Al said...

Oh yeah... Time's strong arrow is angular momentum not entropy. Parity-symmetric mathematical models of the universe must fail. The Equivalence Principle has empirical mass sector parity violations. Somebody should look
.

QUASAR9 said...

ok Bee, so the blog is down time
R&R time away from work & research.

What I meant is that like you had a running theme on the topic of funding, and yes your top ten questions in theoretical physics...

You could have a weekly post on the very questions you like to see asked and discussed.

I guess the comment section is not really adequate space to debate in depth more complex theory ... but I would like to see more people in comment boxes attempt to reply to questions (and offer links) rather than simply trash other theories, often with equally inconclusive theories (or repetition mantras).

I mean I'd really like to hear Lisa Randall explain how her dimensions - beyond her fifth dimension - affect our Universe

or anyone, tell us what we can really expect to come from the LHC, and what will it mean in practice

arivero said...

Most probably the number of innovations in one year will follow f(x)= a - b/t^k.

arivero said...

hmm, f(t)=...
and of course k,a,b > 0

Bee said...

Dear Quasar:

Thank you for your suggestion. Yes, in principle I would like to write more frequently about these questions, and also about the issue of funding. I do so occasionally, and I will keep in mind that you'd like to see it more often.


guess the comment section is not really adequate space to debate in depth more complex theory ... but I would like to see more people in comment boxes attempt to reply to questions (and offer links) rather than simply trash other theories, often with equally inconclusive theories (or repetition mantras).

Sadly enough, this is very true. For many people, online comments are nothing but a public place to advertise their always same arguments and opinions. In a certain sense, this is very tiresome.

Regarding LHC and Lisa Randall, in case you missed it, Tomasso had a very interesting post last week about Steve Gidding's talk, and here are some of Lisa's recent slides (meant to blog about it, but didn't have the time, I just left a comment at Tomasso's).

All the best,

B.

Anonymous said...

"There are hundreds of people using Wick rotations, or working in Euclidean settings, yet none of them can explain why we have a time, or why it has an 'arrow'."

I guess you are not satisfied with current ideas about the arrow of time? [Just put the word arrow into an arxiv search, there are several ideas out there.]
Do you have a general reason for feeling dissatisfied with such ideas? I mean, what form would an explanation of the arrow of time have to take in order to look convincing?

QUASAR9 said...

Hi Bee
From slide 15 - What fraction of energy gets trapped behind horizon?
Now that gets interesting

From Slide 30 - If you see strings, you won’t see black holes
huh? see strings?
Should be able to readily make some gross distinctions about which regime of quantum gravity you are probing
double huh

QUASAR9 said...

From Steve Giddings on microstate-bhs
"Then there is a fourth phase: the black hole reaches the Planck scale. Hic sunt leones: here known physics breaks down. We expect a few particles coming out, with energy of that order of magnitude, but we do not really know the details of what we should expect."

A microstate bh which evaporates, and consequent loss of gravity(?) - and presumably that gravity can be 'recovered' (if only we discover how)

PS - Taking gravity away or losing gravity, is what I call akin to anti-gravity technology.

Bee said...

Hi Anonymous,

indeed, I find the recent discussions very interesting. I meant to express that I'd like to see more efforts in that direction since I happen to think this could be key to other problems as well. Is there a specific scenario you are referring to? I don't think anybody has yet explained why we have a time?

Dear Quasar:

If one collides two extended objects they will in general not cleanly form a black hole horizon that traps all the matter, but part of the matter can escape before the horizon is formed.

Yes, the endstates of the black hole evaporation process are unknown. As I've written in the comment at QDS, it is usually assumed that the black hole makes a final decay into some few particles, but to be honest - we just don't know. There are scenarios that are more or less plausible, but nobody is able to compute that.

I am not sure what you mean with 'taking gravity away'. The black hole evaporates, it radiates energy/matter away, much like the sun. While doing so, its mass decreases since total energy is conserved. That has nothing to do with anti-gravity.

Best,

B.

CarlBrannen said...

"why it has an 'arrow'."

Let R and S be two quantum density matrix states. If they are Hermitian, then tr(RS) = tr(SR) so the transition probabilities equal and there is no arrow of time. But to get the two traces different, you can use non Hermitian states.

Non Hermitian quantum states do not exist in the spinor language, but they do exist in the density matrix / density operator language I use. (I.e. let |a) be a spinor state. Then the corresponding density matrix |a)(a| is automatically Hermitian.)

An example pair of (not normalized) non Hermitian density operator states:

|x)(z| and |z)(y|

The normalization factor for the first is 1/sqrt( (z|x) ).

Bee said...

Hi Carl,

Thanks. To be honest, to me the argument you make seems to be the other way round. We know there is an arrow of time, therefore the theory should be so-and-so. Or do you have any good argument where your scenario arises from?

Best - B.

Rae Ann said...

Probably all fields have their ups and downs. And leveling out too. It's kind of bothersome that people think in terms of "us and them" (US and Europe). Why can't there be more collaboration?

Bee said...

Hi Rae Ann:

Yes, indeed. I think regarding the competition vs. collaboration question the US puts too much weight on the 'competitive edge'. Best,

B.

QUASAR9 said...

Hi Bee, "the end states of microstate blackhole evaporation process are unknown"
It radiates energy & matter away, the mass decreases and total energy is conserved - so there is no loss
(except perhaps that force which bound the matter together, or the gravity that causes singularities in blackholes) But of course we don't expect to see such a thing as a mini-singularity in the LHC - or do we?

Bee said...

Hi Quasar:

Yes, energy is conserved in the black hole's evaporation process.

But of course we don't expect to see such a thing as a mini-singularity in the LHC - or do we?

Well, I for certain don't expect it. First, because I don't think there's a singularity inside the black hole, and second, even if it was it would be hidden by the horizon, so we wouldn't see it.

There has been a paper about naked singularities in fat brane scenarios, which I don't think makes sense (see arguments in this paper.

Best,

B.

Anonymous said...

Bee said: "Hi Anonymous,

indeed, I find the recent discussions very interesting. I meant to express that I'd like to see more efforts in that direction since I happen to think this could be key to other problems as well. Is there a specific scenario you are referring to? I don't think anybody has yet explained why we have a time?"

Why we have time is a tough question :-) Not much work on that. But Hartle has some observations:
http://arxiv.org/abs/gr-qc/0602013

As for the *arrow* of time, there are several ideas: you might like to look at
http://arxiv.org/abs/gr-qc/0502016
http://arxiv.org/abs/hep-th/0611088
http://arxiv.org/abs/hep-th/0410270