Monday, January 11, 2010

A splendid light has dawned on me …

“Es ist mir ein prächtiges Licht über die Absorption und Emission der Strahlung aufgegangen ‒ es wird Dich interessieren. Eine verblüffend einfache Ableitung der Planck’schen Formel, ich möchte sagen die Ableitung. Alles ganz quantisch.”

“A splendid light has dawned on me about the absorption and emission of radiation ‒ it will be of interest to you. A stunningly simple derivation of Planck's formula, I might say the derivation. All completely quantical.”

Albert Einstein in a letter to his friend Michele Besso on August 11, 1916.

The “splendid light” refers to Einstein's insight that stimulated emission (also called induced emission) of light from excited atoms occurs in nature, and that this yields an elementary explanation of Planck's formula for the spectrum of black body radiation.

And, of course, some 46 years later and 50 years ago this May, the “splendid light” of Einstein's idea became a real “splendid light” with the construction of the Laser, based on the principle of stimulated emission of radiation.


  1. I wonder what insights Einstein would be having if he was alive today. I doubt he'd find it so easy.

    He lived in a time when progress could be made via thought experiments - costing no money. It seems that nowadays our experiments have to cost 8 billion dollars.

  2. I think Einstein's situation is quite like that of the Beatles. They were both undoubted geniuses, but they were also the first in when a new field was emerging so there was plenty of opportunity for rapid progress, and there was not nearly so much competition about as there is nowadays. So now we look back on them all as these untouchable geniuses, but there was more than a little touch of "being in the right place at the right time" with both of them.

  3. Hi Andrew,

    I definitely agree with you. It is incredible to see how bold were those results, with though pure and simple ideas... We are all bearing this on our minds when we are doing science, hence the frustration.

    There's a book I like which I commented there:

    In this book lie many of the old founding articles of quantum physics, which were put together in a single volume by Dr B. Escoubès and Dr L. L. Lopes... I have been amazed by the average number of references : 10-15 at best... De Broglie uses only 2 for self-referencing. You can't believe your eyes !

    Definitely another time...

  4. Hi Jerome, yes, definitely "another time".

  5. Hi Jérôme,

    thanks for pointing out this compilation - I didn't know it yet, seems interesting. It is here on Google Books:

    Sources et évolution de la physique quantique: textes fondateurs
    by José Leite Lopes, Bruno Escoubès.

    The Einstein "photon" paper in the compilation, however, is the "photo effect" paper of 1905. By the way, online sources for the 1916 Einstein "Laser paper" are linked here (German text only...)

    Indeed, it's fascinating how ingenious ideas about abstract but "simple" physical models like "excited states of atoms" can have enormous technological impact...

    Cheers, Stefan

  6. Nature's secrets are hard to wrest from her now.

  7. Hi Stefan,

    It’s good of you to draw note of one of Einstein’s lesser known discoveries as so many think of him as just that fellow who came up with relativity. It’s also interesting to note that there is a correlation between this idea and the repercussions of the Bose-Einstein Condensate which now has the same correllated state of matter.

    I also find interesting here with the undertone of many of the comments that Einstein is often over rated as to be more a benefactor of his time than anything else. I would argue although it is certainly true he was born in an age that marked accelerated discovery, that he more then anyone else was an important and perhaps irreplaceable engine in regards ip many of them. I’m reminded reading Richard Feynman saying although he understoof GR as much as he tried to follow the steps that had Einstein arrive at it he was never able to quite understand how he did it. Petsonally I don’t get it these days where instead of trying to hail the accomplishments of people as perhaps to show the better side of human potential we instead try to tear it down and marginalized both the people amd what they did in an effort to make us feel better about our individual failings.



  8. Hi Phil, I take your point, but I just feel that if we're always holding past achievements in such high regard then it's just going to inhibit our future progress, as if "nothing we can do is good enough". Like in music I read the other day that it's about time we "got over" the Beatles, and I would agree. Time to move on, and look to future achievements rather than forever looking backwards.

    It's nether a case of "tearing something down" or our "individual failings" as you put it. It's just a case of "time to move on".

  9. Hi Andrew,

    Yes I understand what you are saying, yet the very success of our species is found in having become able to not lose the lessons of the past as they act to build further our futures, while examining all the way. Einstein himself expressed thisbest when he remided in saying the following:

    “Somebody who only reads newspapers and at best books of contemporary authors looks to me like an extremely near-sighted person who scorns eyeglasses. He is completely dependent on the prejudices and fashions of his times, since he never gets to see or hear anything else. And what a person thinks on his own without being stimulated by the thoughts and experiences of other people is even in the best case rather paltry and monotonous. There are only a few enlightened people with a lucid mind and style and with good taste within a century. What has been preserved of their work belongs among the most precious possessions of mankind. We owe it to a few writers of antiquity (Plato, Aristotle, etc.) that the people in the Middle Ages could slowly extricate themselves from the superstitions and ignorance that had darkened life for more than half a millennium. Nothing is more needed to overcome the modernist's snobbishness.”

    So I agree that we should move on yet would also agree with Einstein this cannot be done well if we forsake our past, if for no other reason then to understand how and why we are so capable/



  10. There is another "equation" fromm
    Einstein, the "viscosity-equation",
    wich stands a bit aside from
    relativity and quantum physics.
    That equation was/is important
    for measurement of molekular weight
    of polymers.
    Staudinger & Co would have had hard
    time without that equation.
    Does somebody know what made Einstein
    to work in that field?

  11. Hi Stefan,

    to me the LASER is THE technical invention of the 20th century.

    Hi Andrew,

    I think you are right when you say that Einstein founds it easy to work on issues physicists are dealing today. Besides the experiment issue, if I read C. Rovelli's book "Quantum Gravity" - of course I am not Einstein :-) - this is very abstract and deals with difficult math.

    Is there any source on the net, where people discussed Einstein's capabilities in math ?

    Best Kay

  12. I'd argue the transistor was at least as THE as the LASER.

  13. Einstein loathed quantum mechanics' deeper implications, especially odd parity. GR does not tolerate fermions absent anomalies. A universe of insufficiently gravitating fermionic matter is subject to corrections.

    Quantized gravitations supplement Einstein-Hilbert action with odd-party Chern-Simons corrections. Particle physics was corrected by Yang and Lee. Start with an odd-parity universe and corrections become defaults.

    This is trivially testable (pdf). If empirically true, 90 years of physical theory are fundamentally incomplete. Somebody should look.

  14. Hi Bee,

    I guess you are right.

    Best Kay

  15. Andrew Thomas wrote: I think Einstein's situation is quite like that of the Beatles. ... Like in music I read the other day that it's about time we "got over" the Beatles, and I would agree.

    ?!?! What ... the ... Quando paramucho mi amore de felice carathon! Mundo paparazzi mi amore cicci verdi parasol! Questo abrigado tantamucho que canite carousel!

    Now you've done it! You've gotten me to lapse into faux-Italiano-Francois-Espanol ... whatever!

    Actually those are the last words of "Sun King" by the Greatest Rock Band, ever, on Abbey Road, which I happen to know you possess. Do those words mean anything?

    Also, whoever wrote that which you read is probably a fan of Simon Cowell, master of mediocrity, so ... be careful what you read!

    Aw, I'm just teasing you Andrew. I know your generation grew up on Elton and Madge and Michael, and the Beatles were ancient history to you (just). Same with me and Elvis.

    Personally, I can't get enough of either Einstein or the Beatles. Far from being JUST in the right place at the right time, they were the RIGHT people for their respective situations. Their talent will forever endure.

  16. Hi Steven,

    As you can see I had a similar reaction to the Einstein comment. The next thing you know Andrew will have us consider to forget about Simon & Garfunkel. Of course if he ever does I`ll just let them . respond to him themselves :-)




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