Quantum

The latest UK paperback edition 

A reader's review from Amazon: Follow the white rabbit!

‘If you think you understand quantum mechanics, you don't understand quantum mechanics’, is a quote commonly attributed to the American Nobel prize winning physicist, Richard Feynman. But no matter who uttered this now famous statement, anyone who has ever had to try to learn quantum mechanics can probably sympathize with it.

In this brilliantly written exposition author, Manjit Kumar, succeeds in, at least, rendering the borders of the foreign country of the quantum open to access: that is, if the traveler has a corresponding smattering of knowledge to start with. Otherwise, it will remain almost impossibly esoteric. This is not for the complete lay person: it is packed, necessarily, with the language of physics. Without that it would not be possible to trace the significant milestones in the development of, what is seen by some as, the most successful theory in the history of science. 

Beginning, at the turn of the Nineteenth Century, with Max Plank, its reluctant originator, Quantum Theory sparked a revolution in the way we conceptualize the basic building blocks of the material world. And, even though few working in the field today, would argue seriously against this now widely accepted world view, few would also lay claim to understanding, completely, its full implications.

Along with each incremental development we learn about the extraordinary individuals who laid brick upon brick to build this sometimes creaking edifice, arguably the greatest of whom, Einstein and Bohr, argued ceaselessly, till the ends of their lives, regarding its merits or otherwise. Their ontological positions could not have been more polarized dealing, as they were, with the ultimate nature of reality and the 'type' of physics best equipped to describe it.

Kumar’s triumph is, seamlessly, to intertwine the arguments this way and that, with the lives of the protagonists and, in the process, illuminate the romance, excitement and processes of scientific endeavour.

Quantum Tops List of Science Books To Read in 2012

In the coming weeks I'll post up a round of QUANTUM related stuff that I have been meaning to for some time, but for now here's an article from last December published in The Hindustan Times about science books worth reading in 2012 and beyond.

Not the Best Books of 2011 list but…

It’s the last day of the year and tradition dictates a list of ‘Best books of 2011’. Apparently, however formulaic this kind of year-ending package may be, readers take to it like a dog takes to a hurled tennis ball. There’s something elemental about lists anyway. Add to that the qualitative tag of ‘Best’ and you’ve got a fix.

The usual practice is to get a bunch of celebrities, including some authors, to briefly name and talk about the titles that excited them most over the last year. We know that Arundhati Roy won’t really talk about Chetan Bhagat’s The Three Mistakes of My Life the same way that Bhagat won’t really talk about Amitav Ghosh’s Sea of Poppies — unless Ghosh has talked about Bhagat’s writings in his up and running blog. So the bulk of the list will be about John Abraham’s discovery of a “spiritually enriching” book — probably Paulo Coelho’s latest mumbo-jumbo dolled up as fiction, Aleph — and about Kiran Bedi’s delight in reading Ravinder Singh’s Can Love Happen Twice?

The purpose of a ‘Best Books of the Year’ list, I suppose, is to tell the reader what recent book he should read if he hasn’t read it already. But what overwhelmingly matters is who’s giving the suggestion. If British historian Simon Schama, for instance, recommends musician Keith Richards’ memoir Life that came out earlier this year — “he can do the words as well as the music” — I can’t see people really rushing to read the book. If I gush about Sri Lankan writer Shehan Karunatilaka’s delightfully gambolling novel Chinaman: The Legend of Pradeep Mathew, chances are slim that people will take my word for it.

In any case, literate (sic) readers would have read most, if not all, the books earlier in reviews. So the list actually serves the function of throwing light on yet another aspect of the public personage’s character — in this case, reading taste — than about the book she or he is talking about. If Shah Rukh Khan states that he likes the writings of Franz Kafka — as he did two weeks ago when he came to this paper’s Delhi office and stated, “Sometimes I sit alone in a dark room and read Kafka and all” — most people are likely to try out the Czech master more than if, say, Pankaj Mishra did the same.

So in the spirit of churlishness and the belief that a ‘Best Books of 2011’ list serves even less purpose than if we had come up with the other con-job, ‘Books To Look Forward to in 2012’ (considering the big titles will be written about when the time comes), here’s a more scientifically approved list that isn’t about who’s reading what or confined to the titles that came out over the last 365 days. It’s for folks who read more than in-flight magazines and believe that reading isn’t just something that kids do but brings pleasure to grown-ups. You know the kind of pleasure you get when you curl up with great books on science.

…the 10 science books you should read in 2012

1. Quantum  Manjit Kumar

Science writer Manjit Kumar’s book is a must-read not because it is hugely original (it derives from standard sources) but because it lets the lay reader side-step the minefield of mathematical complexities that mark quantum mechanics, to let them peer into the minds of Albert Einstein, Niels Bohr, Max Planck and Paul Dirac, the key players and their attempts to explain the world.

2. The Selfish Gene Richard Dawkins

It might have been prudent to rename his reformulation of natural selection as‘The Immortal Gene’, Dawkins remarked in 2006, 30 years after the book was published. No matter, it still remains a vital text on the gene-centred view of evolution.

3. One Two Three…Infinity George Gamow

Though somewhat dated now, George Gamow’s book, which has excellent illustrations, is still regarded as the best introduction to a world of scientific knowledge and understanding. It is said to have launched many illustrious careers in science.

4. The Pleasure of Finding Things Out Richard Feynman

This collection of 13 essays, interviews and addresses (including the Nobel Prize acceptance speech) by physicist Richard Feynman is informal and engaging, with Feynman’s characteristic humour.

5. The Language Instinct Steven Pinker

Language is an instinct and evolved out of natural selection, not a human invention, linguist and psychologist Steven Pinker argued in this 1994 book. The thesis, though, had its critics in Geoffrey Sampson and the late Stephen Jay Gould.

6. Fermat’s Last Theorem Simon Singh

French mathematician Pierre de Fermat’s teasing margin note—of a ‘marvellous proof’ of his theorem—kept mathematicians on tenterhooks for 350 years. Simon Singh reconstructs the intellectual struggle that ended with Andrew Wiles’ solution.

7. The Elegant Universe Brian Greene

Published in 1999, this book tried — and brilliantly succeeded — in peeling off the layers of obscurity surrounding string theory and super-string theory, using metaphors and analogies to explain how the universe works.

8. The Emperor’s New Mind Roger Penrose

This 1989 book by mathematical physicist Roger Penrose disputed the claims of artificial intelligence by arguing that human consciousness is non-algorithmic and its workings cannot be emulated by a digital device like a computer.

9. The Edge of Reason Anil Ananthaswamy

Anil Ananthaswamy, a consulting editor with The New Scientist, travels across the world —from the Chilean Andes to Antarctica to Lake Baikal in Siberia— collecting delightful anecdotes that reveal the human element in scientific processes.

10. Mutants Armand Marie Leroi

In this enlightening (and somewhat disturbing) account, Armand Leroi, a developmental biologist, explores genetic variability in human beings to arrive at an understanding of the human body. Leroi writes with flair, managing to inform and intrigue.

The original article is here.

A Dutch review

A review published earlier this year in Delachendetheoloog:

'Mijn opa las geen romans. In zijn tijd waren boeken en tijdschriften onbetaalbaar. Omdat de mensen bovendien hard moesten werken was er weinig tijd om te lezen. Hij koos zijn lectuur daarom zorgvuldig uit. Zijn voorkeur ging uit naar ‘serieuze’ boeken. Romans gingen nergens over en waren het geld en de aandacht niet waard.

Tegenwoordig is de keus tussen ‘serieuze’ boeken en ‘belletrie’ niet zo wezenlijk meer. Het aanbod van populair-wetenschappelijke boeken is inmiddels zo groot en de boeken zijn zo goed geschreven en gecomponeerd, dat je ‘gewone’ romans met een gerust hart links kunt laten liggen. Het spreekt voor zich dat het genre van het populair-wetenschappelijke boek het goed doet: wij hebben goede leraren nodig om de wetenschappelijke ontwikkelingen te kunnen volgen.

Het boek Quantum van Manjit Kumar is het zoveelste bewijs van de uitstekende kwaliteit van het populair-wetenschappelijke boek. Het boek bevat alles wat een lezer zich kan wensen. Fundamentele inzichten over de inrichting van de werkelijkheid, dramatische ontwikkelingen tussen de grootste geleerden van de vorige eeuw en wijsgerige bespiegelingen over de betekenis van de beschreven gebeurtenissen.

Het boek doet het ontstaan van de kwantummechanica uit de doeken. De geschiedenis van de kwantummechanica wordt vermengd met karaktertekeningen van de belangrijkste geleerden die hebben bijgedragen aan de ontwikkeling van deze theorie en, vooral, over de scheuring die deze theorie veroorzaakt heeft tussen deze geleerden. Het hoogtepunt van dit boek is een beschrijving (alsof je er zelf bij bent) van de Solvay conferentie van 1927, wanneer Bohr en Einstein met elkaar twisten over de vraag of de kwantummechanica compleet is. Kumar bestrijdt het beeld van Einstein als een koppige, oude dwaas die meende dat de kwantummechanica onwaar was. Einstein heeft het formalisme van Heisenberg vrijwel onmiddellijk aanvaard en de experimenten hadden hem er van overtuigd dat de theorie goed was. De theorie geeft de juiste uitkomsten, maar: de theorie geeft ons niet het juiste inzicht in de werkelijkheid! En daarover ging het belangrijke debat tussen Einstein en Bohr. De vraag die de twee verdeelde was of de theorie volledig is en ons alles over de werkelijkheid zelf zegt.

Het debat tussen Einstein en Bohr was feitelijk geen strikt debat over fysische vraagstukken, maar een wijsgerig dispuut over de vraag hoe onze werkelijkheid is ingericht en over de vraag hoe diep de fysicus kan doordringen tot deze werkelijkheid. De auteur van dit boek is overigens uitstekend op de hoogte van dit deelgebied. Hij is fysicus en filosoof. Persoonlijk blijf ik het opvallend vinden dat uit zijn boek blijkt dat alle fysici in de 19eeuw en aan het begin van de 20ste eeuw een levendige belangstelling hebben voor de wijsbegeerte. Planck, Einstein, Heisenberg, Schrodinger, Bohr en alle anderen hebben zich, volgens Kumar, tijdens hun opleiding verdiept in het werk van filosofen. De zakelijke en anti-wijsgerige houding van Weinberg, Feynman en Hawking tref je bij Einstein en Bohr niet aan.

Volgens Niels Bohr moet een natuurkundige zich niet afvragen hoe de werkelijkheid ‘onder de oppervlakte' is. Het heeft alleen maar zin om over de wereld van het kleinste te spreken in termen van meetresultaten. Als de fysicus de beslissing neemt om bepaalde aspecten van de subatomaire werkelijkheid te meten, bemoeit hij zich actief met de natuur: de onderzoeker is niet langer een neutrale waarnemer, maar hij (bedoeld wordt: zijn meetapparatuur) maakt onderdeel uit van deze natuur. Einstein kon niet leven met deze uitleg. Hij meende dat de werkelijkheid op subatomair zich niet anders gedraagt dan de dagelijkse of ‘klassieke’ werkelijkheid. Je moet in staat zijn om de werkelijkheid zelf te bestuderen. De kleinste deeltjes hebben alle eigenschappen die ‘gewone’ tennisballen ook hebben. Het probleem was dat de kwantummechanica, ondanks dat het formalisme juist is, ons geen volledig beeld gaf van de werkelijkheid.

De Salvoy conferentie van 1927 was geheel gewijd aan de ‘nieuwe’ kwantummechanica. Alle geleerden keken naar Bohr, de koning van de kwantummechanica, en Einstein, die beschouwd werd als de paus van de fysica. Op de conferentie zelf zei Einstein weinig. Maar Bohr en Einstein logeerden in hetzelfde hotel. En in de avonden en de ochtenden waren ze niet in staat om elkaar met rust te laten. Einstein bedacht ingenieuze argumenten waaruit moest blijken dat de nieuwe fysica onvolledig is: het was een goede rekenmethode, maar beslist geen theorie die ons interessante fysische inzichten gaf in wat zich afspeelt op subatomair niveau.

De tegenvoorbeelden van Einstein hielden Bohr uit de slaap. Gedurende de nacht was hij bezig om een deugdelijk weerwoord te bedenken. Een enkele keer vond hij het antwoord pas in de ochtend. Maar uiteindelijk droogde de stroom bedenkingen van Einstein op. Hij weigerde echter om zijn standpunt te veranderen. De nieuwe theorie was in zijn ogen nu eenmaal onvolledig.
Kumar beschrijft hoe het meningsverschil tussen Einstein en Bohr zich voortsleept door de jaren heen. Waar mogelijk zochten de twee geleerden elkaar op. Maar uiteindelijk lukte het Einstein niet om formeel aan te tonen dat de theorie onvolledig is. Hij weigerde echter om zijn zienswijze te veranderen. Dit leverde hem bij de jongere generatie fysici de naam op een halsstarrige en ouderwetse man te zijn- dit strenge oordeel komt begrijpelijkerwijs voort uit teleurstelling over het feit dat de beroemdste fysicus het belang van hun werk niet wil erkennen.

Bohr en Einstein bleven vrienden van elkaar en ze respecteerden elkaar zeer. Maar de relatie bekoelde wel door het aanhoudende onderlinge meningsverschil. Einstein weigerde op het laatst zelfs om nog uitgebreid te twisten over de kwantummechanica. De laatste maal ontmoetten Bohr en Einstein elkaar bij toeval. Bohr was op bezoek bij een collega van hen die, evenals Einstein, werkzaam was op het Princeton instituut. Opeens sloop Einstein de kamer van de collega binnen om stiekum wat tabak te nemen uit de tabakspot die op tafel stond. Enige tijd later werd Einstein ziek. Hij weigerde zich te laten behandelen. Nauwelijks een jaar later stierf ook Bohr. Hoe belangrijk het oordeel van Einstein voor Bohr altijd geweest is bleek volgens Kumar uit de tekening die op het bord in zijn werkkamer stond: een van Einsteins ingenieuze tegenvoorbeelden.

Pas na de dood van Bohr en Einstein werd het geschil met fysische middelen beslecht. De jonge fysicus Bell, door Kumar op sympathieke wijze beschreven, ontdekte hoe men met een experiment zou kunnen vaststellen of non-localiteit –er lijkt op subatomair niveau geen ‘afstand’ te bestaan- een 'echte' eigenschap is van de kwanta. Uit de experimenten van Aspect blijkt vervolgens dat de klassieke visie van Einstein niet te verdedigen is.

Drama en natuurkunde zijn in dit boek zo ideaal met elkaar verweven dat je zowel de mensen die een hoofdrol hebben gespeeld goed leert kennen als de ontwikkeling van de fysica leert begrijpen en de daarmee gepaard gaande filosofische en fysische problemen. Kumar is in staat om de fysica op een zakelijke manier uit te leggen, zodat je voldoende op de hoogte bent van de problemen waar Einstein en Bohr zich het hoofd over breken. Hij bedient zich van een droge, zakelijke stijl. Zijn verteltrant is echter in het geheel niet sober. Het boek is meeslepend, wordt hier en daar zelfs ‘dramatisch’ zonder sentimenteel te worden. Zo spannend kan wetenschap dus zijn!'

If anyone out there reads Dutch, do let me know what it really says! I have a vague idea via Google translate.

Another review of Le grand roman de la physique quantique

A blog review by ErMa:

'L'histoire du making of de l'équation célébrissime, ces quelques signes abstrus ayant hanté les nuits de bon nombre de taupins et qui figurent désormais au patrimoine de l'humanité :






Disons-le tout de go, ce bouquin est passionnant, car il réunit trois ingrédients essentiels :

1) Un sujet (scientifique) d'intérêt et d'envergure : l'histoire d'une révolution conceptuelle majeure dans l'histoire de l'humanité, initiée en Allemagne au début du XXe siècle. Un changement de paradigme, illustré par l'émergence à marche forcée, au fil d'expériences de pensée d'une subtilité diabolique et de confirmations expérimentales d'une précision époustouflante, d'un cadre conceptuel contraire à nos intuitions, dans lequel le déterminisme (si rassurant) n'a plus sa place. Une démarche que certains, notamment le plus illustre d'entre eux (Einstein) réfuteront avec obstination jusqu'à leur mort : "Dieu ne joue pas aux dés".

Pourtant, malgré tout, la théorie aura déjoué toutes les tentatives de remise en question et gouverne actuellement et de façon silencieuse nombre d'applications de notre vie de tous les jours, notamment tout ce qui a trait à l'électronique.

2) L'Histoire, avec un grand H. Celle encore récente (moins de cent ans). Une époque où la science européenne rayonnait sur le monde et où son épicentre se situait en Allemagne, plus précisément du côté de Göttingen et Berlin. On sait ce qu'il advint par la suite. La montée de l'hitlérisme, l'exil des savants, le désastre de la deuxième guerre mondiale, la résurgence de l'autre côté de l'Atlantique du coté de Princeton. Oui, ce bouquin a également le petit parfum amer du paradis perdu...

3) Et puis enfin, l'histoire avec un petit h. Le destin individuel d'êtres de chair et de sang qui émergent derrière les figures tutélaires désormais inscrites dans nos encyclopédies : Bohr, de Broglie, Heisenberg, Schrödinger, Dirac, Pauli, avec, en contrepoint de leurs fulgurances, leurs faiblesses, leurs entêtements, leurs emportements, leurs erreurs.

Au delà de la vulgarisation d'un concept - pourtant a priori pas facile à comprendre - et réussie avec virtuosité, le succès de l'entreprise tient au talent déployé par Manjit Kumar pour faire de cette matière brute un véritable roman axé sur la psychologie de personnages hors du commun rendus à leur condition d'hommes comme vous et moi, en prise directe avec le grand souffle de l'histoire.

Un bel exemple de pédagogie à méditer. A une époque où il est de bon ton de s'auto-proclamer "nul en maths", rêvons qu'il puisse s'agir d'une leçon pour les pédagogistes de tous poils, apprentis sorciers participant au suicide actuel de l'éducation nationale, soixante ans seulement après la mort d'Einstein.'

L' Express review of the French Edition of Quantum

A review of the French edition of Quantum, or Le grand roman de la physique quantique as it's called in France, published in June but just forwarded to me by a friend:

'Bruxelles, octobre 1927. L'élite des physiciens de la planète est réunie au parc Léopold pour le congrès le plus important et le plus dramatique de la physique moderne. Dix-sept des vingt- neuf personnalités sont des Prix Nobel ou de futurs Nobel, dont Marie Curie, seule femme de cet aréopage d'hommes. Thème officiel : électrons et photons. En réalité, ces savants doivent accepter ou rejeter les premiers éléments de la physique quantique. Et remiser au placard les théories de la relativité qui ont valu à Einstein son prix Nobel en 1921. C'est un choc de titans, chacun affûtant ses armes pour ou contre le "quantum" pour lequel Max Planck a reçu le Nobel en 1919. La plupart de ces hommes se connaissent, ont même travaillé ensemble. Pourtant, la lutte sera sans merci. Acculé par ses pairs, Einstein se bat comme un lion.

Le talent de Manjit Kumar, physicien et philosophe, est de nous faire vivre cette bataille en direct, comme les étapes qui l'ont précédée et les années de conflit qui ont suivi. Il nous fait entrer dans l'intimité de ces génies, leurs origines, leurs engagements, leur passion pour cette science qui est en train de vivre sa plus grande révolution. On les suit depuis l'enfance jusqu'à la recherche de l'université européenne ou américaine qui veut bien les accueillir pour des travaux rarement pris au sérieux. Alors qu'ils ont donné naissance à tout ce qui fonde la modernité, depuis l'atome jusqu'à l'ordinateur. L'arrivée de Hitler au pouvoir en Allemagne force les savants juifs à s'exiler. Dans les années 1950, la commission McCarthy chasse d'Amérique les chercheurs de gauche.
L'auteur analyse avec brio les différentes thèses, expose les méthodes. Il sait aussi remettre dans son contexte l'apostrophe célèbre d'Einstein - "Dieu ne joue pas aux dés" - et l'invention par Erwin Schrödinger de ce chat mythique, vivant ici tandis qu'il est mort là-bas. Surtout, il nous fait suivre les péripéties du combat, partisans de Planck et de Bohr contre admirateurs d'Einstein. L'affrontement est si violent qu'on attend avidement chaque nouvel épisode, comme s'il s'agissait d'un film policier qui serait intitulé "le grand thriller du quantique". Aujourd'hui, alors que la théorie qui réconcilierait la relativité et la physique quantique apparaît encore comme un Graal inatteignable, il est bon de méditer sur cette épopée.'

A Review of the Spanish edition of Quantum

A review of the Spanish language edition of Quantum published today by Noticias de la Ciencia y la Techologia:

'Aunque la ciencia sigue avanzando de forma imparable, hubo una época en la que la física hizo un enorme e inesperado salto adelante. Esta era brillante se cerró durante el Quinto Congreso Solvay, en octubre de 1927, donde se reunieron 29 físicos, 17 de los cuales eran o acabarían siendo premios Nobel. Basta con observar la fotografía conmemorativa de la reunión para certificar su importancia: Schrödinger, Pauli, Heisenberg, Dirac, de Broglie, Bohr, Planck, Einstein, Curie, Lorentz... Suficiente materia gris como para cambiar el mundo.

El más famoso episodio de este congreso fue sin duda el debate entre Einstein y Bohr, dos de los mayores investigadores y teóricos de la historia, y dos científicos que ofrecían visiones no coincidentes de la realidad. Hubo otros congresos Solvay, y otros encuentros entre ambos físicos, pero ninguno como el de 1927. Sus teorías rivales fueron un estímulo brutal para ellos y para sus seguidores, que así hicieron avanzar la física de forma decisiva.

En “Quántum”, Manjit Kumar nos ofrece una amplia perspectiva histórica sobre la ciencia cuántica, y nos cuenta lo que ocurrió en Solvay y entre las personalidades que allí concurrieron. Es una historia de ciencia, pero también filosófica, de rivalidades, de personas.

El libro es una obra de divulgación científica tanto como un texto de historia y una biografía. Es así como consigue atrapar al lector, quien en sus páginas aprenderá sobre física cuántica y más aún sobre los individuos que desarrollaron la teoría, en un entorno de trabajo de principios del siglo pasado.

Por esta vía, Kumar, que es también físico, ha dado a luz un libro que se ha convertido en un auténtico éxito en Gran Bretaña y otros países. Y no es extraño, pues el producto es el fascinante relato de un debate entre dos genios, y al mismo tiempo, una obra que trata de contarnos dos visiones distintas de la naturaleza de la realidad.

Sin duda, estamos ante un libro para disfrutar desde múltiples puntos de vista. El interesado por la historia de la ciencia, el amante de la física, el lector de la filosofía moderna, el estudiante, todos encontrarán algo provocador y atractivo en él. No deben perdérselo.'

You can read an extract in Spanish here.
Translation to follow once I can convince a Spanish speaker to translate...

James Hannam reviews Quantum

James Hannam, author of God's Philosophers: How the Medieval World Laid the Foundations of Modern Science reviewed Quantum on his blog - Quodlibeta. I've taken the liberty of reproducing it below:

'Manjit Kumar’s book Quantum: Einstein, Bohr and the Great Debate about the Nature of Reality is a difficult project triumphantly accomplished. In popular history of science, the aim is to mould the history and the science together without compromising too much on either. When the science in question is quantum mechanics, an author already has his work cut out trying to explain it to the general reader. Another challenge is that the history of the quantum is about a clash of personalities and philosophical viewpoints. Turning that into a readable story is no mean feat. But Kumar has succeeded on both fronts.

The debate at the heart of Quantum is how to interpret the strange physics of the sub-atomic world. On one side was Albert Einstein. Despite the difficulty many of us have with relativity, it is actually a well-behaved physical theory that does not require us to compromise on the basic concepts of objective reality or cause and effect. Quantum mechanics, on the other hand, disposes of such foundations: it is a subjective realm where the observer appears to affect the result of experiments and where randomness is indelibly built in. Einstein could never accept this. He thought there were “hidden variables” behind quantum mechanics that would transmute it into a deterministic theory. “God does not play dice”, he said many times.

The other side of the argument was led by Niels Bohr, the greatest Dane since Tycho Brahe. Bohr developed the Copenhagen interpretation of the quantum which embraced its strangest aspects. Bohr accepted that the motion of sub-atomic particles can only be predicted as probabilities and that the experimenter is part of the same system as the thing being observed. Einstein set Bohr a number of fiendish puzzles to show that quantum mechanics was inconsistent and so incomplete. But every time, Bohr solved the problem. Eventually, after Einstein’s death, the Irish physicist John Stewart Bell developed a way to experimentally test one of the quantum paradoxes called non-locality. But, to date, the theory appears to pass even this trial.

All this has left science with a massive hangover. It is not as widely appreciated as it should be that the two crowning achievements of modern physics, relativity and quantum mechanics, are completely incompatible. It is not just that they give different results. They inhabit different metaphysical universes. Scientists have tended to assume that quantum mechanics is the more fundamental theory and string theory is an attempt, unsuccessful so far, to combine it with relativity.

I have a suspicion that current crisis in physics is a function of abandoning the metaphysical framework of a deterministic and objective universe. String theory has returned to the failed ancient Greek model of pure rationalism where clever ideas can never be tested. In the meantime, anyone who wants to understand the background to the The Trouble with Physics chronicled by Lee Smolin can do no better than to read Manjit Kumar’s Quantum.

If you haven't read James's book, check it out. It was shortlisted in 2010 for the Royal Society Science Book Prize.

'a brilliant history of quantum theory'

A review of Quantum by Paul Thomas on the Freedom in a Puritan Age website:


'Quantum mechanics is both one of the most important scientific theories of the twentieth century and one of the least understood, admittedly even by physicists themselves. Quantum theory challenges both the laws of ‘classical physics’ and throws up philosophical questions about our ability to truly understand, not just the microphysical world of the atom, but the everyday, macrophysical world which we inhabit.

In telling the story of quantum theory, Kumar has written a fascinating narrative history that interweaves scientific theory and individual biography against the background of broader historical events.

Kumar introduces us to not just the main adversaries around whom the debate over quantum theory revolves — Albert Einstein and Niels Bohr — but a supplementary cast of some of the greatest scientific minds of the twentieth-century: the conservative patriarch of modern science, Max Plank; charismatic New Zealander, Ernest Rutherford; dogmatic quantum theorists Werner Karl Heisenberg and Max Born; the ‘shy’ Paul Dirac; Wolfgang Pauli, known as “The Wrath of God” for his critical mind; the ‘scandalous’ (and sometime alley of Einstein) Erwin Schrodinger; and post-WWII Irish scientist John Bell, who came up with a famous theorem to test Einstein and Bohr’s positions. At the heart of the book though is Einstein, the most famous scientist in history, the man whose name has become a synonym for ‘genius’, and whose continued questioning of a theory he had helped initiate saw him become an increasingly isolated and discredited figure.

Quantum theory begins in 1900 with Max Planck’s discovery that the energy of light and all other forms of electromagnetic radiation could only be emitted or absorbed by matter in ‘bits’, bundled up in various sizes; ‘quantum’ being the name he gave these individual packets of energy. As Kumar says, this was a radical break from the long held belief that energy was emitted and absorbed continuously. For Planck, the quantising of energy was a pragmatic solution to another problem that he thought he would get rid of in time.

Einstein saw the revolutionary and ‘heretical’ potential of Planck’s temporary expedient. In 1905, Einstein published four papers that would eventually launch him to international stardom, including his special theory of relativity. But it was the first of these papers, in which he put forward the theory that light was made up of particle-like quanta or photons (as they were later called), that Einstein considered the most important.

In 1913, the young Bohr applied Einstein’s light-quanta theory to the electrons within an atom and their ability to emit or absorb energy; but in doing so, he violated certain tenets of accepted physics, leaving what happens within the atom completely to chance. For Einstein, it was as if one were to let go of an apple, but instead of it falling to the ground it was suspended for some unspecified length of time, before shooting off in some undetermined direction.

Nevertheless, as with Planck and his original ‘bundles’ of energy, Einstein was prepared to abandon the ‘causality’ of classical physics and tolerate random ‘probability’ for the time being, in the hope it would be removed with further scientific developments.

By the mid-1920s, however, Einstein had grown uneasy with the very probability he had introduced into the atom. It was in writing to Max Born about his theory in 1926 that Einstein expressed his growing disquiet about quantum mechanics, and in which he first uttered his famous remark that ‘God is not playing dice’. Nevertheless, he had been the unwitting inspiration for one of the greatest developments in the understanding of the quantum: Heisenberg’s uncertainty principle.

Heisenberg had discovered that quantum mechanics forbids the precise determination of both the position and the momentum of a particle at any given moment. The more accurately the one is measured, the less accurately the other can be known or predicted, as any attempt to measure an electron automatically interferes with its trajectory. As such, for the likes of Bohr, Heisenberg, and what became known as the Copenhagen school of quantum mechanics, there can be no such thing as a quantum reality free from observation. An electron simply does not exist at any place until a measurement is performed to locate it. It is the act of observation that makes ‘real’.

For Einstein, and a few like Schrodinger, there must be an objective reality free from observation and accessible to human reason. This isn’t just a scientific question, but a philosophical one. The belief that there is no such thing as an observer-free objective reality in the atomic realm affects what we can say about nature in general and, for Einstein, risks reducing science to ‘uninspired empiricism’. However, although this is ‘the great debate about the nature of reality’ to which Kumar refers, this is an argument that is never fully had-out between the main protagonists; as Bohr, unlike Einstein, is clearly not keen to step outside the uncertainty of the subatomic realm and into a real-world philosophical debate.

Amongst the strengths of Kumar’s account is placing these debates within their historical context. The uncertainty at the heart of quantum physics reflected the uncertainty of the inter-war years, which eventually saw Einstein emigrate to the United States, and brought an end to the international conferences at which these debates took place. But Kumar’s real achievement is to rehabilitate the reputation of the later-Einstein, on whose side you have no doubt Kumar is.

From the beginning Einstein argued that quantum theory was incomplete; yet as its application became increasingly successful, he became marginalised and an almost lone voice against the increasing orthodoxy of the Copenhagen Interpretation. Today, however, many physicists would agree with Einstein that quantum mechanics is an incomplete theory. As Kumar says, although Einstein never managed to deliver a decisive blow in his encounters with Bohr, his challenge was sustained and thought provoking:

“Einstein never put forward an interpretation of his own, because he was not trying to shape his philosophy to fit a physical theory. Instead he used his belief in an observer-independent reality to assess quantum mechanics and found the theory wanting.”

Kumar has written a brilliant history of quantum theory from its origins to the present; capturing, in particular, the excitement of the interwar years as the greatest scientific minds of the twentieth-century criss-crossed Europe, between conferences and university departments, meeting in train stations to snatch every opportunity to discuss the latest theories. Quantum evokes that world and takes you into those complex debates, without distracting from a fascinating story.'

Quantum - Spanish Edition

The Spanish edition of Quantum is now available online here and in bookshops throughout Spain thanks to Peter Tallack and Louisa Pritchard. Many thanks to my translator David González Raga, María Alasia and everyone else involved in its production at Kairos.

Quantum - Italian Paperback Edition

The Italian paperback of Quantum was published at the end of May and is available online here at Italian Amazon and in bookshops throughout Italy. My thanks to all those involved in its production at Mondadori by especially to my Italian translator Tullio Cannillo.

Quantum paperback published in USA and Canada

Today Quantum is published in paperback in the USA and Canada. Thanks to everyone at Norton. Love the new cover. You can buy it online here.

Quantum in paperback in French and German

Quantum is now available in French and German paperback editions and on sale, as they say, in all good bookshops in France and Germany.

You can buy the French here and the German here

Solvay 1927 - A film clip

If you want to see some extremely rare footage of some of the participants leaving the Solvay conference in October 1927. Shot by the American Irving Langmuir, its just under 3 minutes long and shows Einstein, Bohr, Schrodinger, Heisenberg, Pauli, Born, de Broglie, Dirac and others after a day discussing quantum mechanics. The commentary is provided by Nancy Thorndike Greenspan, the author of an excellent biography of Max Born called The End of the Certain World.

'An Enlightening Book on Einstein and the Quantum Theory Debate'

Jay Lehr, science director of the Heartland Institute reviews Quantum:

'While I was a student at Princeton University in the early 1950s I had a literally nodding acquaintance with Albert Einstein. During my freshman year he walked past my dormitory every day on his way to the Institute for Advanced Study. I often found myself on the sidewalk as he passed by, and we nodded to each other. I have read many an interesting biography of his life since, but none more interesting than Quantum, by Manjit Kumar.

Quantum is a biography not just of Albert Einstein’s life but also his thought processes. It also provides insight into the dozens of famous theoretical physicists who influenced and aided him in his work.

Complex Science Explained
Quantum theory, which attempts to describe the atomic and subatomic worlds, is for most people a byword for mysterious, impenetrable science. For many years it was equally baffling for the world’s most brilliant physicists. Here the author gives us a dramatic and superbly written account of this fundamental scientific revolution and the divisive debate at its core.

Simply reading Quantum may not make one an immediate expert on quantum theory, but the chronology of every great contribution to the physics of quantum theory—beginning in 1858 and continuing to the present—will be worth the price of the book.

The most complex and difficult-to-understand intricacies of quantum theory in no way reduced the joy I felt in reading this book and following the journey of so many great scientists as they researched and published their discoveries. Interestingly, these discoveries were not often verified in a laboratory, but they were agreed upon because they accorded with physical observations and allowed for reasonable mathematical solutions.

Interesting Narratives, Theories
In one of the most compelling discussions in the book, Kumar describes a conference held in Belgium in 1927. Of the 29 people invited to the conference, 17 went on to receive the Nobel Prize. At times Kumar made me feel like I was in the room. Heisenberg, Planck, Born, and Schrödinger came alive for me as I read these passages.

In an enlightening scientific discourse, Kumar explains the concept of entanglement, a quantum phenomenon in which two or more particles remain inexorably linked no matter how far apart they are. He also explains the intriguing quantum theory in which Dr. Schrodinger’s cat can be simultaneously dead and alive.

Quantum is not a book for everyone. But if you have a great deal of scientific curiosity and enjoy reading about some of the greatest scientific minds in history, you will certainly enjoy this book.'

Original review can be read here.

Edinburgh International Science Festival

A review of my talk at the Edinburgh International Science Festival by Keir Liddle of The 21st Floor:

'In front of a packed auditorium Manjit Kumar takes to the stage. Behind him is displayed an image of the “first team” of physics: Einstein, Bohr, Dirac, Planck, Curie, Schrödinger, Heisenberg and the other luminaries that attended the famous Solvay conference in 1927. Arguably the greatest minds working in the field gathered together in one place. Einstein alone being the most famous and well known physicist since Newton for his theory of relativity.

This conference was a pivotal point in quantum physics and one at which quantum theories two prize-fighters, Niels Bohr and Albert Einstein, did battle with various thought experiments to test Bohrs Copenhagen interpretation. According to this interpretation of quantum physics you can only say a particle exists when you try to measure and observe it. Einstein took exception to this as he believed that the universe did not simply go away when you did not observe it.

“I like to think that the moon is there even if I am not looking at it.”

Manjit weaved together the intriguing tale of the people who were behind the biggest discoveries in the physics of the incredibly small with an affable style and a genuine affection for the subject. Too often science and scientists can appear cold, distant and removed from human endeavour and it is valuable and important that Manjit reminded us that scientists are driven by human motivations, ambitions and that there is a very human joy in exploring and understanding the fundamental principles of the universe.'

The Meeting of Minds

I first saw the photograph of those gathered at the fifth Solvay conference, which was held in Brussels from 24 to 29 October 1927, in a biography of Albert Einstein. This was in 1979, when I was just 16. I wondered what brought these people together, and soon learned that the picture included most of the key players involved in the discovery of the quantum, and the subsequent development of quantum physics. With 17 of the 29 invited eventually earning a Nobel Prize, the conference was one of the most spectacular meetings of minds ever held.


When I was 18, I was given a print of the above photograph as a present. Many years later I began to think about it as a possible starting point for a book about the quantum. In the photograph there are nine seated in the front row. Eight men, and one woman; six have Nobel Prizes in either physics or chemistry. The woman has two, one for physics, awarded in 1903, and another for chemistry, awarded in 1911. It could only be Marie Curie. In the centre, the place of honour, sits Albert Einstein. Looking straight ahead, gripping the chair with his right hand, he seems ill at ease. Is it the winged collar and tie that are causing him discomfort, or is it what he has heard during the preceding week? At the end of the second row, on the right, is Niels Bohr, looking relaxed with a half-whimsical smile. It had been a good conference for him. Nevertheless, Bohr would be returning to Denmark disappointed that he had failed to convince Einstein to adopt his Copenhagen interpretation of what quantum mechanics revealed about the nature of reality.

Instead of yielding, Einstein had spent the week attempting to show that quantum mechanics was inconsistent, that Bohr's 'Copenhagen interpretation' was flawed. Einstein said years later that:

This theory reminds me a little of the system of delusions of an exceedingly intelligent paranoic, concocted of incoherent elements of thoughts.

It was Max Planck, sitting on Marie Curie's right, holding his hat and cigar, who discovered the quantum. In 1900 he was forced to accept that the energy of light, and all other forms of electromagnetic radiation, could only be emitted or absorbed by matter in bits, bundled up in various sizes. 'Quantum' was the name Planck gave to an individual packet of energy, with 'quanta' being the plural. The quantum of energy was a radical break with the long-established idea that energy was emitted or absorbed continuously, like water flowing from a tap. In the everyday world of the macroscopic, where the physics of Newton ruled supreme, water could drip from a tap, but energy was not exchanged in droplets of varying size. However, the atomic and subatomic level of reality was the domain of the quantum.

Bohr discovered that the energy of an electron inside an atom was 'quantised'; it could possess only certain amounts of energy and not others. The same was true of other physical properties, as the microscopic realm was found to be lumpy and discontinuous. Not some shrunken version of the large-scale world that we humans inhabit, where physical properties vary smoothly and continuously, where going from A to C means passing through B. Quantum physics, however, revealed that an electron in an atom can be in one place, and then, as if by magic, reappear in another without ever being anywhere in between, by emitting or absorbing a quantum of energy.

By the early 1920s, it had long been apparent that the advance of quantum physics on an ad hoc, piecemeal basis, had left it without solid foundations or a logical structure. Out of this state of confusion and crisis emerged a bold new theory; known as quantum mechanics, with Werner Heisenberg and Erwin Schrödinger, third and sixth from the right in the back row, leading the way. In 1927 Heisenberg made a discovery. It was so at odds with common sense that he initially struggled to grasp its significance. The uncertainty principle said that if you want to know the exact velocity of a particle, then you cannot know its exact location, and vice versa.

Bohr believed he knew how to interpret the equations of quantum mechanics; what the theory was saying about the nature of reality. Questions about cause and effect, or whether the moon exists when no one is looking at it, had been the preserve of philosophers since the time of Plato and Aristotle. However, after the emergence of quantum mechanics they were being discussed by the twentieth century's greatest physicists.

The debate that began between Einstein and Bohr at the Solvay conference in 1927, raised issues that continue to preoccupy many physicists and philosophers to this day; what is the nature of reality, and what kind of description of reality should be regarded as meaningful? 'No more profound intellectual debate has ever been conducted', claimed the scientist and novelist CP Snow. 'It is a pity that the debate, because of its nature, can't be common currency.'

When Einstein and Bohr first met in Berlin in 1920, each found an intellectual sparring partner who would, without bitterness or rancour, push and prod the other into refining and sharpening his thinking about the quantum. 'It was a heroic time,' recalled Robert Oppenheimer, who was a student in the 1920s. 'It was a period of patient work in the laboratory, of crucial experiments and daring action, of many false starts and many untenable conjectures. It was a time of earnest correspondence and hurried conferences, of debate, criticism and brilliant mathematical improvisation. For those who participated it was a time of creation.'

Planck, Einstein, Bohr, Heisenberg, Schrodinger, Born, Pauli, De Broglie, Dirac, the leading lights of the quantum revolution, are all there in that picture.

Originally posted on Nature.com

Paperback of American Edition

This is the cover of the US paperback edition to be published by Norton on 9 May 2011. My thanks to all involved in its production.

French Edition of Quantum

The cover of the forthcoming French edition. Soon I'll post a round-up of Quantum related stuff from recent months.

Quantum makes Booklist's Top Ten for 2010

Quantum chosen as one of the top ten science and technology books of the year by Booklist. They say: 'Kumar illuminates a pivotal episode––Bohr’s triumph over Einstein in their debate over quantum physics––in an accessible and dramatic mix of biography, history, and science.' See the full list here.

Amazon Reader's Review: 'Feeds the brain and the heart'

Steve from Cardiff had this to say about Quantum on amazon.co.uk:

'Like a good novel, this kept me gripped to the very end thanks to a perfect balance between hard science and human interest. The first thing you notice about the book is the detail. Copiously researched, Kumar has pulled together a truly impressive array of material, both personal and professional, constructing a rich history that transports you to the subject's golden age and to the lives of the key players. He tells a story so engrossing and so detailed that I felt surprisingly moved towards the end. Yes, by a book on quantum theory.

In terms of the science, there are some first-class explanations from blackbody radiation and the photoelectric effect through to EPR and Bell's Theorem, with 30+ pages of end notes. Although the history is structured around the debate between Einstein and Bohr, other key players are afforded considerable coverage - not just the obvious ones like Planck, Rutherford, Heisenberg, Schrödinger, de Broglie and Born, but also (and to his credit) some of the lesser known figures - Sommerfeld, Uhlenbeck, Compton - whose crucial contributions to the field frequently go unmentioned in books and articles on this subject.

The great debate itself is a tremendously invigorating one. Both Einstein and Bohr agreed that quantum mechanics was correct. Where they disagreed was in whether or not it was complete. In fact the implications of this disagreement went deeper, calling into question the fundamental role of physics itself, and whether there is even such a thing to be measured as an independent objective reality. On this, the author's background in physics and philosophy are put to good use. Overall then, this is a captivating fusion of science, history, philosophy and biography, and a great way to feed the heart and the brain.'

Top Ten Science Books for 2010 on Amazon.com

Quantum makes the list of the top ten science books on Amazon.com at number 5. See the full list here.

'This book may be dangerous to your health,' warns reviewer

Jeffery Bairstow, contributing editor of Laser Focus World had to this say about Quantum:

"I think I can safely say that nobody understands quantum mechanics," claimed Nobel laureate Richard Feynman in 1965, some 10 years after Albert Einstein's death. Not even the great father of atomic science himself could have risen to the challenge of sorting out atomic physics just after completing his theses on relativity. "I thought a hundred times as much about the quantum problems as I have about general relativity problems," said Einstein, in the late 1930s. The quantum literally became Einstein's demon.

But wait a minute–now comes a thick new book that purports to cover all you need to know on the thorny subject of quantum mechanics. The book is Quantum: Einstein, Bohr and the Great Debate about the Nature of Reality, by Manjit Kumar. Warning: This book may be dangerous to your health. I almost could not put this book down–I began missing meals and ignoring family member needs.

For once, here is a well-written and highly informative book on a difficult subject. Over the years, I have examined several books by leading authors in this field, but this is the only one that lives up to its title. By reading this book, you may find that you have developed an informed layman's view of quantum mechanics. The book reads more like a novel than a beginning textbook for vigorous demos of proofs.

The book differs from conventional biographies in that it uses a timeline from the days of the pioneers (J.J. Thomson of Britain, Max Planck of Germany, etc.) to contemporary scientists (Anthony Leggett, Richard Feynman, etc.). So what you are reading seems to be a series of essays about Max Planck and the "gang of nine." In rough historical order, the list looks like this: Planck, Rutherford, Pauli, Heisenberger, Bohr, Schrodinger, Einstein, Dirac, Marie Curie, and Bragg. Some list!

Before you read this book, I recommend that you take close look at the first of the B&W photos in the middle of the book. This is a splendid group photo taken at the fifth Solway conference, in October 1927. The two dozen attendees comprise all the key researchers in the field plus a few observers sent to keep their professors abreast of new developments. The assembled brain power is staggering! These meetings were sponsored by Ernst Solvay, a Belgian industrialist who made a fortune from the manufacture of sodium carbonate.

Such "quantum summit meetings" were key conferences for the leading scientists of that time. But there were many larger formal meetings held in London, Berlin, Copenhagen, and other major cities. For example, it was not unusual to have a thousand attendees at the London meetings of the distinguished British Royal Society.

Often the meetings were also supported by leading celebrities of the day. For example, in 1930, the playwright George Bernard Shaw was the master of ceremonies for a lavish fund-raising event at the plush Savoy Hotel in London. Einstein was the guest of honor. Shaw wittily commented that, given the intellectual firepower in the room, "I had to talk about Ptolemy and Aristotle, Kepler and Copernicus, Galileo and Newton, gravitation, and relativity and modern astrophysics, and heaven knows what…"

Shaw then summarized the current state of play as "Ptolemy made a universe which lasted 1,400 years. Then Newton also made a universe which lasted 300 years. Einstein has made a universe and I can't tell you how long that will last." Einstein laughed as loudly as anyone at Shaw's witticisms.

Kumar deftly interposes the developments in quantum physics with the rarely described personal lives of the major players. This combination of the scholarly work with the personal events is rarely attempted with physicists, but Kumar succeeds where others have failed miserably. His sweep is both broad and narrow with surprising success.

Quantum in the USA

Quantum reviewed in The LA Times on 8 August:

'If thinking about the quantum theory doesn't make you schwindlig (dizzy), then you haven't understood it, Niels Bohr, its great patriarch, famously (well, famously among physicists) remarked. Quantum mechanics lies at the subatomic base of physical reality — and ruptures any attempts to visualize it. This doesn't worry many physicists, who use quantum mechanics to correctly calculate the behavior and attributes of the stupefyingly small and choose to disregard its weirdness. It certainly doesn't worry most nonphysicists; we go about our lives anyway, heedless of the Problem. It worried Albert Einstein profoundly until the day he died. Are you smarter than Einstein?

The British science writer Manjit Kumar has written an intellectual history of the upending, in the 1920s, of classical, Newtonian physics, whose descriptions of an objective, causal reality coincide with our intuition. But quantum theory is counterintuitive. It tells us that a subatomic particle — an electron, say — is in no particular place until it is observed. (Since you cannot see an electron, "observed" here means determining its position experimentally.) It tells us that if you want to know how fast the electron is traveling, then you will have to give up knowing just where it is. It tells us, even, that an electron can be in two places at the same time. The same electron. The various predictions that quantum theory makes have been confirmed in countless experiments.

I recall having all this explained to me in the mid-1960s, over a three-hour lunch in an Italian restaurant in midtown Manhattan, by a frightened science journalist who had just learned that the bit about finding an electron in two places at once had been confirmed by the so-called double-slit experiment. Suffice to say that contemplating this made me and my lunch partner so schwindlig that by the last half-hour neither one of us was sure that the other was actually there. What Bohr might also have said is that once you grasp, however dimly, the implications of quantum theory, your life will never be the same.

This is a very good and thorough history of the quantum revolution, which is not to say that it's a particularly easy read. Unlike many books about physics for laymen, there are no equations in it — except for a couple of "simple" ones about an inch long describing the uncertainty principle, Werner Heisenberg's discovery that you cannot simultaneously determine the position and momentum of a subatomic particle. But the ideas are difficult, as you might expect from the book's subtitle, heralding "the Great Debate About the Nature of Reality."

The principals in this great debate are Bohr, whose physics institute championed the counterintuitive "Copenhagen interpretation" of quantum physics, and Einstein, who objected to Bohr's "renunciation of the representation of a reality ... independent of observation." Einstein believed, to put it simply, that an electron exists — and exists in a particular place — regardless of whether it is being observed. Bohr, and his disciple Heisenberg, believed that "until an observation or measurement is made, a microphysical object like an electron does not exist anywhere," and that "it was no longer possible to make the separation that existed in classical physics between the observer and the observed."

Kumar leads the reader as carefully as he can through the thicket of permutations that led to the completion of the theory and its eventual experimental confirmation (although his description of the Einstein-Podolsky-Rosen paradox, a vain attempt to dethrone it, may make you feel as if you're meeting yourself coming and going). He leavens the mind-bending with sketches of the remarkable human beings involved in this godlike enterprise. Among them: Max Planck, the "reluctant revolutionary" who discovered and named the quantum in 1900, when he was "forced to accept" his own data showing that radiation is emitted and absorbed in packets. The insouciant Heisenberg, young enough to be able to turn his back on classical concepts with no regrets. Erwin Schrödinger, 14 years older, who invented a rival mechanics while vacationing with his mistress in the Alps and refused to accept nature's fundamental discontinuity — even to the point of collapsing on a visit to the Bohrs after a marathon debate with his host ("Bohr sat on the edge of the bed and continued the argument" ). And the acerbic Wolfgang Pauli, nicknamed "The Wrath of God," whose intelligence scared people and who read Einstein's papers on general relativity under his desk in high school "when bored by a particularly tedious lesson."

Pauli is said to have rocked back and forth while he was thinking hard. You might try this on your way through Kumar's book. It's a wonderful trip and one you should embark on if you're interested in just what exactly is at the bottom of the garden.'

Quantum - an audio review

From Tower Review

'Leaping into the history of quantum theory'

A review from the Providence journal in the US:

'Something deeply hidden had to be behind things,” Albert Einstein thought as a child, thereby expressing the human need and compulsion to see through, behind and beyond the world that we inhabit in order to discover religious truths, scientific laws or cosmic visions.

In this clearly written and understandable analysis of quantum theory, the major discovery of 20th-century physics, Manjit Kumar, who has degrees in both philosophy and physics and is the author of “Science and the Retreat from Reason,” tackles an epic task and interweaves his chronological saga with biographies and backgrounds of all the major physicists who were involved — from Einstein, the “Pope,” to Niels Bohr, the Danish “King,” from Paul Dirac’s silences to Wolfgang Pauli’s sarcastic asides, from French princes to German professors, laboratories and “thought experiments” to the quantum leaps of physicists from the major universities and institutes in Munich, Gottingen, Copenhagen and Berlin.

When Max Planck in 1900 discovered the quantum, “the indivisible packet of energy,” as well as matter, he was unaware that he had destroyed centuries of Newton’s mechanical, deterministic and materialistic vision of the cosmos, undermining notions of gravity and clearly defined orbits.

In 1905, Einstein discovered that light was a particle, made up of quanta, and thus upended the century-long belief in light as a wave, though Newton had thought in terms of particles of light as well. Einstein went on to conjure up relativity, in which matter and energy, forever separate before 1905, became interchangeable, limited only, as in all things, by the speed of light.

Kumar makes the fifth Solvay conference in Brussels in October 1927 the centerpiece of this fascinating, intriguing tale of speculations made and shattered, friendships formed and strained, lavish correspondences that exploded and collapsed, and the heady rush to publish papers in leading journals in order to stake out the latest possible theory and reveal yourself on the cutting edge of the new, confounding vision of the subatomic world.

Politics also intervenes, with the Nazis condemning “Jewish physics” and the flight into exile of many German scientists. At that conference, Einstein and Bohr squared off in terms of what all the quantum mechanics, matrices and wave equations meant, wrestling with one another’s theories in terms not of animosity but of camaraderie.

Bohr had decided that everything was both a particle and a wave — the central conundrum of quantum theory — mutually exclusive but necessary. However, one could measure the radioactive traces of electrons and photons on photographic screens only as particles or waves, never simultaneously. Because he believed that the act of measurement always interferes with and disturbs what we are seeing, we can only see snapshots of the quantum realm. “An unobserved electron does not exist,” he declared. Uncertainty, discontinuity, chance and accident govern all things. Only statistical probabilities worked.
Einstein, on the other hand, believed that the subatomic realm exists independent of human observation. Quantum theory had proved itself, but it was incomplete, and that possibility of incompleteness has dominated the study of physics ever since. How does measurement interfere? Is there a border between the quantum realm and our own?

Kumar has done a splendid job of explaining complex theories and describing the people involved with discovering them, mired in cultural and historical upheavals that haunted all of them. This is a necessary, mesmerizing and meticulous volume.'

'Pulsar' on Quantum

'Pulsar' from Belgium on the League of Reason site gave Quantum this stellar endorsement:

‘I just finished "Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality", by Manjit Kumar.

It's one of the best pop-science books I've ever read, and I cannot recommend it highly enough. The book describes the history of quantum mechanics, notably the first three decades of the 20th century, and all the major characters involved - physics, biographic info and European history are intertwined into a real page-turner. It's absolutely fascinating to see how Planck, Einstein, Bohr, Rutherford, De Broglie, Born, Pauli, Dirac, Heisenberg and Schrodinger constantly inspired each other in their obsession to understand atoms and radiation.

The central part is the Great Debate between Einstein and Bohr about the Copenhagen Interpretation of QM, the relation between physics and reality, and Bell's theorem to test the completeness of the theory. I must say, this book shows Einstein's views of QM in a way I knew little of. Often, Einstein is depicted as a relic who couldn't keep up with the latest physics and never really 'got' QM. But in reality he knew damn well what he was doing (and he convinced Schrodinger, who came up with his cat thought experiment). The standard interpretation of Bohr has dominated the teaching of QM ever since, but this book asks the question whether this domination is really justified. It might be time for a new revolution in physics...

A must-read!’

Book addict on Quantum

'Addicted to books' blogger Tracy had this to say about Quantum:

'This book is a gem, a history of quantum mechanics, not just about Einstein and Bohr, but about those other giants of physics and their discoveries - Planck's original accidental discovery of the quantum, Rutherford's discovery of the atomic nucleus, de Broglie's wave-particle duality, Pauli's exclusion principle, Heisenberg's uncertaintly principle, and Schrödinger's wave equation (and infamous cat). More than this, Kumar's book brings those Nobel prize-winning scientists to life - Heisenberg's rivalry with Schrödinger, Pauli, the sharp-witted Austrian who rarely surfaced before noon, de Broglie, both a German prince and a French duke and the quiet Englishman Dirac, bullied by his overbearing father.

Having brought you up to speed on the nature of quantum mechanics, lucidly explaining both the experimental evidence and the thought experiments beloved of Einstein, the author then hits you with the real argument, the interpretation of quantum mechanics: What does it really mean? What is the nature of reality? In the 'observer-independent reality, quantum theory is incomplete ' corner was Einstein, whereas Bohr and the majority of quantum physicists at the time were very much in the 'probablistic, observer-dependent reality' corner - Einstein's famous argument that 'God does not play dice with the Universe' countered by Bohr's response of 'But still, it cannot be for us to tell God, how he is to run the world.' And still the debate continues.

Manjit Kumar's book explains the science and the arguments beautifully-clearly and fairly. Highly recommended to anyone who likes science history and essential reading for anyone who is studying any kind of science. The kind of book that really does make you feel slightly more intelligent after you've read it, for a few weeks, anyway, until you forget Pauli's exclusion principle (no two electrons in an atom can occupy the same quantum state), de Broglie's equation linking wavelength and momentum gradually fades, Planck's constant, h, draws a blank and all you're left remembering is Schrödinger's cat, his famous thought experiment about a cat in a box, whose fate is determined by random radioactive decay of an atom.'

Lessons for today from the Golden Age of Physics

Norman Lewis posted this insightful piece at www.futures-diagnosis.com which I'm taking the liberity of reprinting here:

WHEN RESEARCH MAKES QUANTUM DEVELOPMENT SENSE
The call this week by Lord Browne, the former BP chief executive, for a sweeping review of the UK’s £4bn-a-year science budget to emphasise projects with the potential to bring short-term industrial benefits, has sparked a fury amongst scientists. (See ‘Common room clashes with boardroom on science budget’, Financial Times. This is precisely what we warned against in the Big Potatoes Manifesto where we argue in principle 4 ‘For Useless Research’ that research remains the bedrock upon which the flow of innovation ultimately depends – a bedrock that is increasingly being questioned and undermined in our short-termist recessionary times.

Lord Browne’s instrumentalism certainly makes re-stressing this point timely and urgent. But the correctness of this fundamental research proposition was forcibly driven home to me during my recent holiday when I had the luxury and sheer delight of reading Manjit Kumar’s tour de force Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality .

This is an absolute must for all those supporters of Big Potatoes. It describes in a remarkably entertaining and accessible fashion, the history of science’s fundamental revolution – quantum physics and mechanics – and the remarkable intellectual battle between Albert Einstein and Niels Bohr and other brilliant young scientists who were at the heart of this inspiring story.

More importantly, it reveals some critical insights into the processes and interactions that led to a scientific revolution which gave rise to the innovations we now take for granted: the transistor, the computer, the World Wide Web, the communications revolution.

UNEXPECTED OUTCOMES
Kumar shows that when these great physicists formulated quantum mechanics from 1900 to 1930, they were trying to understand the fundamental laws of the universe, not invent something of great economic importance. Their quest was the sheer beauty of solving some of the most baffling and abstract theoretical questions. The implications of their quest were so far-reaching it impacted almost everything, transforming sister disciplines like chemistry, for example. Today, all chemists and material scientists are trained extensively in quantum mechanics. Biologists like Francis Crick, who won the 1962 Nobel Prize in Medicine for the discovery of DNA, realized many years ago that the laws of physics and quantum mechanics ultimately govern even biology.

Quantum mechanics is necessary to engineer solid-state devices such as transistors, which are the building blocks of electronics and computers. Understanding semiconductors (the building blocks of transistors), or any material cannot be fully grasped with classical physics alone (i.e. physics known before the discoveries of quantum mechanics and relativity). Without quantum mechanics, the “information age” (and much of modern science) would not exist today. The inventions of the computer, the transistor, the World Wide Web and the laser used in fibre optics, (the basis for a global telecommunications industry) owe their existence to quantum mechanics and are worth trillions of dollars.

But to stress this point again, these were unexpected outcomes. The pursuit was science, the quest for purity and the beauty of an unassailable proof – and a closer approximation of reality.

There were three things about the book that really caught my attention, which are so germane to the debate we have started with the Big Potatoes Manifesto:

THE ‘LIMITS’ OF HUMAN KNOWLEDGE
Kumar relates the story about Max Planck, the father of Quantum who at the age of sixteen enrolled at Munich University to study physics because of his burgeoning desire to understand the working of nature. Planck spent three years at Munich which were to have a big impact on him, mainly because he was advised to give up physics as ‘it is hardly worth studying physics anymore’ because there was nothing important left to discover. Planck went on to become the father of quantum mechanics because, as he discovered, there was certainly a lot more to discover about how the world works. Planck reacted against the narrowness and conservatism of his peers. He defied the attitude, which we seem to accept today, that mankind had somehow reached the limits to knowledge. Instead his openness and willingness to question existing orthodoxy unleashed a scientific revolution, the creation of new knowledge and ultimately, the development of remarkable innovations that changed life in the 20th century.

PEERS COMMITTED TO THE GREATER GOOD
The second striking point Kumar brings out in his examination of the interaction of this extraordinary group of scientists was their willingness to engage each other as professionals in a common quest for truth. First, what united them was a belief in objective truth. Second, that despite different opinions (and often bitterly at odds) they were nevertheless united as pioneers committed to something greater than themselves.

This is illustrated by the example of Max Planck’s endorsement of Einstein for membership of the Prussian Academy of Sciences in 1913 despite fundamentally disagreeing with his position on light-quanta. Planck’s proposal contained the following paragraph: ‘In sum, it can be said that among the important problems, which are so abundant in modern physics, there is hardly one in which Einstein did not take a position in a remarkable manner. That he might sometimes have overshot the target in his speculations, as for example in his light-quantum hypothesis, should not be counted against him too much. Because without taking a risk from time to time it is impossible, even in the most exact natural sciences, to introduce real innovations’ (p52)

Not only do we see a remarkable willingness to recommend a fellow scientist despite disagreeing with him but the clear connection between disagreements and risk as critical to scientific advance.

What a stark contrast with today where contestation is regarded as a religious infraction against ‘truth’ (as in the ‘Climategate’ debacle) and where risk is consciously prevented by concentration on what we already know or what Lord Browne thinks can be safely developed. Planck reveals what science is really about in contrast with today’s instrumentalism and manufacture.

THE BEAUTY AND NOBILITY OF SCIENCE
The third and final striking point in the book is the nobility of the young scientists involved in this rich period of scientific discovery. For them, as in the example of Ernest Rutherford, exploiting their research for financial gain was seen as a distraction from the really important goal of making a scientific reputation for themselves. Rutherford who had started working on the detection of ‘wireless’ waves (radio waves) chose instead to pursue his academic passion (in contrast to others working in this field like the Italian Guglielmo Marconi who amassed a fortune).

This is not to suggest that exploiting scientific discoveries were wrong or that the people who did were somehow flawed. Far from it. It highlights how the pursuit of science requires those types of individuals who regard it as a noble calling and are given the freedom to pursue it regardless of measurable outcomes (as we would have it in today’s crude management-speak). Kumar reveals how the young men at the centre of the quantum revolution were driven not only by their own self- belief (and no doubt, huge egos), but also by the pursuit of something greater than material wealth – a belief in scientific and human progress.

Of course that is precisely what is being questioned today, which is why the media concentrates its attention on the exploiters of science rather that present-day pioneers. So the founders of Google are feted for creating Google whereas in the past we would be looking for the scientific contribution they might have made towards humanity’s body of knowledge. Today we celebrate exploitation rather than the wonder of science underpinning these achievements.

The question this raises is how we will ever create a culture that places greater value in the pursuit of knowledge rather than on its results?

As the world discovered through Max Planck, everything had not been explained. Kumar’s book is a great reminder that there is no such thing as natural limits and that the worst dimension of a culture of limits is that it constrains the thing we have an abundance – human ingenuity, perseverance and the noble ability to rise above petty egos, jealousies and parochialism to benefit humanity as a whole.

Kumar’s book is definitely Big Potatoes and should be read widely.

Born with Quantum history in the family

Carey Born, the granddaughter of the Max Born, the great quantum physicist who was instrumental in the development of matrix mechanics (he even taught Heisenberg what a matrix was) and put forward the probabilistic interpretation of Schrodinger's wave function (for which he was awarded the Nobel Prize) wrote this on amazon.co.uk:

'Manjit Kumar has produced a brilliant, insightful account of the quantum story. Through a compelling narrative he interweaves the ideas, events and personalities involved in the paradoxical quest for the truth about uncertainty. The book is a fascinating read about this tumultuous and revolutionary period in the history of science. Highly recommended'.

Another reader's view of Quantum

'A brilliant read', says Steve Carleysmith on amazon.co.uk

'I found this a fascinating read. If you are interested in how science works and the power of personalities, you will love this book. Using really well researched personal details of the lives of the key figures, Kumar shows how quantum science developed and led to the scientific and philosophical conflict between Bohr and Einstein - a debate that continues to this day. What is real and what is only observed? Kumar blends biography and quantum theory, covering probably the most exciting period in the development of science and thought.'