Introducing Volume 15 of The Collected Papers of Albert Einstein

From fraudulent science to hope for European reunification, the newest volume of The Collected Papers of Albert Einstein conveys the breakneck speed of Einstein’s personal and professional life. Volume 15, covering June 1925 to May 1927, is out now!

Volume 15: The Berlin Years
Writings & Correspondence, June 1925-May 1927, Documentary Edition

Edited by Diana Kormos Buchwald, József Illy, A. J. Kox, Dennis Lehmkuhl, Ze’ev Rosenkranz & Jennifer Nollar James

Princeton University Press, the Einstein Papers Project at the California Institute of Technology, and the Albert Einstein Archives at the Hebrew University of Jerusalem, are pleased to announce the latest volume in the authoritative COLLECTED PAPERS OF ALBERT EINSTEIN. This volume covers one of the most thrilling two-year periods in twentieth-century physics, as matrix mechanics—developed chiefly by W. Heisenberg, M. Born, and P. Jordan—and wave mechanics—developed by E. Schrödinger—supplanted earlier quantum theory. The almost one hundred writings, a third of which have never before been published, and the more than thirteen hundred letters demonstrate Einstein’s immense productivity at a tumultuous time.

Within this volume, Einstein grasps the conceptual peculiarities involved in the new quantum mechanics; falls victim to scientific fraud while in collaboration with E. Rupp; and continues his participation in the League of Nations’ International Committee on Intellectual Cooperation.


Every document in The Collected Papers of Albert Einstein appears in the language in which it was written, and this supplementary paperback volume presents the English translations of select portions of non-English materials in Volume 15. This translation does not include notes or annotation of the documentary volume and is not intended for use without the original language documentary edition which provides the extensive editorial commentary necessary for a full historical and scientific understanding of the documents.

Translated by Jennifer Nollar James, Ann M. Hentschel, and Mary Jane Teague, Andreas Aebi and Klaus Hentschel, consultants


Diana Kormos Buchwald, General Editor

THE COLLECTED PAPERS OF ALBERT EINSTEIN is one of the most ambitious publishing ventures ever undertaken in the documentation of the history of science.  Selected from among more than 40,000 documents contained in the personal collection of Albert Einstein (1879-1955), and 20,000 Einstein and Einstein-related documents discovered by the editors since the beginning of the Einstein Papers Project, The Collected Papers provides the first complete picture of a massive written legacy that ranges from Einstein’s first work on the special and general theories of relativity and the origins of quantum theory, to expressions of his profound concern with international cooperation and reconciliation, civil liberties, education, Zionism, pacifism, and disarmament.  The series will contain over 14,000 documents as full text and will fill close to thirty volumes.  Sponsored by the Hebrew University of Jerusalem and Princeton University Press, the project is located at and supported by the California Institute of Technology and has made available a monumental collection of primary material. It will continue to do so over the life of the project. The Albert Einstein Archives is located at the Hebrew University of Jerusalem. The open access digital edition of the first 14 volumes of the Collected Papers is available online at

ABOUT THE SERIES: Fifteen volumes covering Einstein’s life and work up to his forty-eighth birthday have so far been published. They present more than 500 writings and 7,000 letters written by and to Einstein. Every document in The Collected Papers appears in the language in which it was written, while the introduction, headnotes, footnotes, and other scholarly apparatus are in English.  Upon release of each volume, Princeton University Press also publishes an English translation of previously untranslated non-English documents.

ABOUT THE EDITORS: At the California Institute of Technology, Diana Kormos Buchwald is professor of history; A. J. Kox is senior editor and visiting associate in history; József Illy and Ze’ev Rosenkranz are editors and senior researchers in history; Dennis Lehmkuhl is research assistant professor and scientific editor; and Jennifer Nollar James is assistant editor.

Jeffrey Bub & Tanya Bub: There are recipes for Pi. But quantum mechanics?

There’s a recipe for Pi, in fact quite a few recipes. Here’s one that dates to the fifteenth century, discovered by the Indian mathematician and astronomer Nilakantha:


For the trillions of decimal places to which the digits have been calculated, each digit in the decimal expansion of Pi occurs about one-tenth of the time, each pair of digits about one-hundredth of the time, and so on. Its still a deep unsolved mathematical problem to prove that this is in fact a feature of Pi—that the digits will continue to be uniformly distributed in this sense as more and more digits are calculated—but the digits aren’t totally random, since there’s a recipe for calculating them.

Quantum mechanics supplies a recipe for calculating the probabilities of events, how likely it is for an event to happen, but the theory doesn’t say whether an individual event will definitely happen or not. So is quantum theory complete, as Einstein thought, in which case we should try to complete the theory by refining the recipe, or are the individual events really totally random?

Einstein didn’t like the idea that God plays dice with the universe, as he characterized the orthodox Copenhagen interpretation of quantum mechanics adopted by Niels Bohr, Werner Heisenberg, and colleagues. He wrote to his friend the physicist Max Born:

I find the idea quite intolerable that an electron exposed to radiation should choose of its own free will, not only its moment to jump off, but also its direction. In that case, I would rather be a cobbler, or even an employee in a gaming house, than a physicist.

But Einstein was wrong. Consider this puzzle. Could you rig pairs of coins according to some recipe so that if Alice and Bob, separated by any distance, each toss a coin from a rigged pair heads up, one coin lands heads and the other tails, but if they toss the coins any other way (both tails up, or one tails up and the other heads up), they land the same? It turns out that if each coin is designed to land in any way at all that does not depend on the paired coin or how the paired coin is tossed—if each coin has its own “being-thus,” as Einstein put it—you couldn’t get the correlation right for more than 75% of the tosses. This is a version of Bell’s theorem, proved by John Bell in 1964.


What has this got to do with quantum randomness? The coin correlation is actually a “superquantum” correlation called a PR-correlation, after Sandu Popescu and Daniel Rohrlich who came up with the idea. Quantum particles aren’t correlated in quite this way, but measurements on pairs of photons in an “entangled” quantum state can produce a correlation that is close to the coin correlation. If Alice and Bob use entangled photons rather than coins, they could simulate the coin correlation with a success rate of about 85% by measuring the polarizations of the photons in certain directions.

Suppose Alice measures the polarizations of her photons in direction A = 0 or A′ = π/4 instead of tossing her coin tails up or heads up, and Bob measures in the direction B = π/8 or B′ = −π/8 instead of tossing his coin tails up or heads up. Then the angle between Alice’s measurement direction and Bob’s measurement direction is π/8, except when Alice measures in the direction A′ and Bob measures in the direction B′, in which case the angle is 3π/8. According to the quantum recipe for probabilities, the probability that the photon polarizations are the same when they are measured in directions π/8 apart is cos2(π/8), and the probability that the photon polarizations are different when they are measured in directions 3π/8 apart is sin2(3π/8) = cos2(π/8). So the probability that Alice and Bob get outcomes + or − corresponding to heads or tails that mimic the coin correlation is cos2(π/8), which is approximately .85.

Bell’s theorem tells us that this pattern of measurement outcomes is closer to the coin correlation pattern than any possible recipe could produce. So God does play dice, and events involving entangled quantum particles are indeed totally random!

BubTanya Bub is founder of 48th Ave Productions, a web development company. She lives in Victoria, British Columbia. Jeffrey Bub is Distinguished University Professor in the Department of Philosophy and the Institute for Physical Science and Technology at the University of Maryland, where he is also a fellow of the Joint Center for Quantum Information and Computer Science. His books include Bananaworld: Quantum Mechanics for Primates. He lives in Washington, DC. They are the authors of Totally Random: Why Nobody Understands Quantum Mechanics (A Serious Comic on Entanglement).

Introducing a New Biophysics Textbook

Bialek_Biophysics_caseAre you headed to Philadelphia for the Biophysical Society’s 57th Annual Meeting (#bps13) starting on February 2nd? They are expecting over 6,000 biophysicists to attend. It’s a great opportunity to see what is new in the field. And speaking of what is new in the field, professors and students, you will want to check this out – it is the textbook you’ve been waiting for:

Biophysics: Searching for Principles
by William Bialek

William Bialek provides the first graduate-level introduction to biophysics aimed at physics students. Interactions between the fields of physics and biology reach back over a century, and some of the most significant developments in biology–from the discovery of DNA’s structure to imaging of the human brain–have involved collaboration across this disciplinary boundary. For a new generation of physicists, the phenomena of life pose exciting challenges to physics itself, and biophysics has emerged as an important subfield of this discipline. Featuring numerous problems and exercises throughout, Biophysics emphasizes the unifying power of abstract physical principles to motivate new and novel experiments on biological systems.

–Covers a range of biological phenomena from the physicist’s perspective
–Features 200 problems
–Draws on statistical mechanics, quantum mechanics, and related mathematical concepts
–Includes an annotated bibliography and detailed appendixes
–Instructor’s manual (available only to teachers)
–Illustration Package available
–Supplementary Materials available

William Bialek is the John Archibald Wheeler/Battelle Professor in Physics at Princeton University, where he is also a member of the multidisciplinary Lewis-Sigler Institute for Integrative Genomics, and is Visiting Presidential Professor of Physics at the Graduate Center of the City University of New York. He is the coauthor of Spikes: Exploring the Neural Code.

“Bialek’s excellent book bears the stamp of both his originality and technical prowess. What I look for when I read a book is something unique that I know I won’t find anywhere else. Bialek delivers that in spades on a topic of great interest to scientists of all stripes.”–Rob Phillips, California Institute of Technology

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We hope you enjoy Philadelphia and stay warm!