نظريۀ كوانتومی

Very Short Introductions #069

by John C. Polkinghorne, حسین معصومی همدانی (Translator)

‫اين كتاب برای عموم نوشته شده و تا جايی كه موضوع آن اجازه می‌دهد كتابی روشن و خوشخوان است.
‫خواننده‌ای كه تا اندازه‌ای با مبانی مكانيك كوانتومی آشنا باشد در اين كتاب چيزهايی خواهد ديد كه معمولاً در كتاب‌های درسی نمی‌آورند و در سر كلاس درس نمی‌گويند و اگر دل به مطلب بدهد چيزهای بسياری از اين كتاب خواهد آموخت و به ويژه با مشكلات مفهومی نظريۀ كوانتومی و تعبيرهای گوناگون آن آشنا خواهد شد.

Genres: Science, Physics, Nonfiction, Philosophy, Quantum Mechanics, Audiobook, Popular Science

156 pages, Paperback

First published January 1, 2002

About the author

John Charlton Polkinghorne is an English theoretical physicist, theologian, writer and Anglican priest. A prominent and leading voice explaining the relationship between science and religion, he was professor of Mathematical physics at the University of Cambridge from 1968 to 1979, when he resigned his chair to study for the priesthood, becoming an ordained Anglican priest in 1982. He served as the president of Queens' College, Cambridge from 1988 until 1996.

Reviews

[Alice · Rating 5 out of 5]

Explains the unexplainable in the nicest and clearest way.

[Steve · Rating 2 out of 5]

Polkinghorne, a student of the great Paul Dirac, may have achieved an undeniable eminence in his field, but I'm afraid I was left mostly unimpressed by this attempt to communicate his ideas. Not only one of the weaker books on quantum theory, but also one of the weaker entries in the Very Short Introduction series as a whole (well, of the few dozen I've read).

Two main problems I had with it:

1) Mathematical: It assumes too much of the reader in the way of complex numbers, probability amplitudes, etc. Of course some assumptions of knowledge have to be made, even in something calling itself an introduction - but the author could have done more to elaborate on some of the more vital mathematical content, even without resorting to formulae.

2) Another problem - a surprising one - is its philosophical flakiness. Polkinghorne seems to make some astonishingly flimsy arguments, particularly in the section on positivism. For someone so intellectually gifted, his sloppy reasoning here disappointed me.

And to be frank, the explanations are really not the best. I don't doubt Polkinghorne is (was) a great scientist. Just a shame that, on the basis of this book, he seems to have fallen short as a scientific communicator.

If you want to get up to speed on the fundamentals of this subject, there are more informative and inspirational books out there:

- Quantum: A Guide for the Perplexed - twice the price, but will probably leave you ten times more informed.
- Six Easy Pieces - Feynman's compendium has a good section of quantum theory.
- Fabric of the Cosmos - Brian Greene's magnificent tome also offers a solid foundation.

[Darwin8u · Rating 4 out of 5]

VSI#69.
Quantum Theory is a challenging subject to present in VSI form. You've got about 100 (+/- 30 pages) to give an intelligent, compelling introduction to one of the most challenging area of science directed at amateurs and/or undergraduates. Oof! Polkinghorne does an amazing job. Most of my reviews of the 40+ VSIs I've read tend to fall between 3 and 4 stars. This one is different. First, Polkinghorne lands the information. He presents a difficult subject matter in an intelligent way. Second, he does it with style. I was telling my wife one of the reasons i love reading about Quantum Physics is it is drama AND poetry. You've got great characters, but the subject matter itself lends itself to metaphors and poetry (see Carlo Rovelli).

Case in point with this book: in a section dealing with the difficulty in understanding Quantum Theory (the math is easier than understanding what's actually going on), the author dismissing scientists who might settle for not understanding the detailed character of particular physical properties, and calls that approach "a treason of the clerks". What a beautiful use of that idiom. Perfect. No notes sir.

[Benjamin Stahl · Rating 3 out of 5]

One more book down in my seemingly futile quest to properly wrap my head around quantum theory. This one, as far as books on the subject broadly speaking go, and also as part of the useful VSI series, is a pretty good one. I still have many questions, many of which are probably stupid, but at least Polkinghorne's treatment of the topic manages not to feel too dry or incomprehensible.

[Nathan · Rating 3 out of 5]

A good, short overview of quantum theory, but unfortunately does not to a very good job as an introduction, making assumptions about the reader's knowledge of the subject. I fortunately already had some background with quantum theory, but others may have trouble making their way through this book

[Abhijeet Jain · Rating 3 out of 5]

The first half of the book is great, briefly explains all the theories involved in formation of Quantum theory.
The second half wasn't something I was expecting, it was way to tough for me though I have read few other books on the same subject no one talked about the actual maths. The author tried to explain some mathematics related to quantum theory very briefly which wasn't actually needed in a book meant for general public. For people who don't have major in Quantum theory will surely feel uneasy in the second half.
Verdict : it's worth reading, leave it when mathematics hits you !

[Jacob Alcott · Rating 3 out of 5]

While it may not be my place to comment on the content of this book, I did not go to school nor have I had any formal training in quantum theory, and this is only the third book I've read on the topic, I can say that the organization and readability of this book is one of the better that I have read in the field. Polkinghorne does a good job of delivering theory while keeping the math accessible in the back of the book, for those who can access it.

Something I have found commonplace in book on this subject is a section, usually the last chapter, dedicated to ontological, metaphysical, and other philosophical implications. This is where I find myself most comfortable with ideas. Polkinghorne does a great job here in laying out the philosophical considerations while staying out of conjecture in his own right. I am curious to see what his own contemplations would look like on the matter, especially knowing that he has written other books on theology and practices as an Anglican Priest.

Being a student of Dirac, there is considerable praise given to the renowned physicist. This is neither a good or bad thing, but important for the reader to know in a field that is full of speculation and, at times, disagreement.

All in all, this is a fine book on the subject and a great addition to the "Very Short Introduction" series for Oxford Press.

[Michael Grizer (He-Him) · Rating 3 out of 5]

I'm not sure who the intended audience of this book is. I took a semester of quantum mechanics in college and this still went way over my head. Someone needs to publish a very short introduction to the very short introduction. Or maybe the subject just can't be dumbed down enough for people like me.

[Fakhour Mohammed · Rating 4 out of 5]

I think I can safely say that no one understands quantum mechanics - Richard Feynman

[J · Rating 3 out of 5]

As someone who loves quantum theory, I was hoping this book would be "a very short introduction." Well... it was short, and it was an introduction! But oftentimes it was kind of hard to understand. I really appreciated that the information wasn't just surface level and it really did go into the details with quantum theory. Sometimes you get books where it's just information I've seen over and over again in other media.

However, the lack of necessary pictures for explanations and clearer sentences made it sometimes pretty difficult to understand what the author was actually trying to say. And the few pictures that existed were often difficult to comprehend. Many times I would've appreciated something like a step-by-step process with images, but it was usually kind of just explained with a large paragraph, which just made my head spin. The author also tended to assume the audience had knowledge they (I) did not. I understood a good chunk of this book, but it's unfortunate that what might've been the best parts for me just made me lost. (It didn't help that I already generally knew the content in the introduction section, but that's more tailored to me.) 3.25 stars.

[Carson Phillips · Rating 4 out of 5]

It’s difficult to say this was a good introduction since I’m the audience being introduced. I’ll trust the physicists on whether it was an honest to the field. I still do not really have a good grasp on quantum theory, but I can feel the wheels slowly turning. The book did help me to understand more about observational influences and what the wave functions are describing. I thought I was starting to understand the philosophical conundrums because I, rightly, seem to have identified the wave-particle duality not as ontological but epistemological. However, entanglement somewhat throws that out of the window. It seems that the spookiness here is probably more to do with thinking of these as how reality really is instead of a more approximate description of reality for predictability. I think one issue is that the gap between the physicist and the layman is so vast that they assume laypeople know that things like the wave function are mere description, not reality. Physicists also are not good philosophers, so they themselves think of their maths and heuristics as real metaphysics, leading to an undue realism. Hopefully, further reading on the topic should help refine my thoughts. Overall, Polkinghorne did a great job on this introduction in my uneducated opinion.

[Kaylie · Rating 3 out of 5]

Was a decent history of the foundations of quantum mechanics in the beginning, but explanations of quantum theory were a little wishy washy in the end despite the mathematical appendix; not really sure if I understood the concepts properly lol.
Found it really funny though, that Heisenberg passed his oral exam for his PhD at the lowest level just because he couldn't explain the proof for a concept bc he never bothered with experimental physics (despite being brilliant and top of his class for all other concepts+ eventually developing the uncertainty relations).

[Shriviyas R. · Rating 5 out of 5]

Understood like 5%😍

[Toby Brown · Rating 4 out of 5]

The perfect book on quantum theory. It encapsulates the fundamental dichotomies of very small physics. Is it a wave, is it a particle? is it both? Is the cat alive or dead? Do you understand it while reading this book but not understand it as soon as you put it down? All those questions are both answered and unanswered while reading the book. Which took a lot longer than its seductively slim size suggested! There’s a useful glossary at the back and, while most of the maths flew past me at the approximate speed of light, it does do its best to cater to the humanities students of this world. Good luck!

[Christopher · Rating 3 out of 5]

The insights of quantum physics are key to many technologies we use today, and yet most people are unaware of the key discoveries made already a century ago now, being familiar only with the "classical physics" of their basic high school or university science classes. Though I had an inkling of what I was missing out on from being a great reader of hard science-fiction, I needed to familiarize myself with the basics of field, and John Polkinghorne's slim volume in the Oxford "A Very Short Introduction" series seemed convenient.

Indeed, at little over 100 small-format pages, Polkinghorne does present enough of the field to make you feel like you know the ramifications, even if the real theory is forever beyond you. Polkinghorne only brings in one advanced mathematical concept in the body of the text, eigenvectors, and even that single recourse to maths will probably be too daunting for most readers. Furthermore, even without mathematics, Polkinghorne's writing can often become very egg-headed and opaque, and I was very surprised that his editor at Oxford University Press let all this stand. Clearly no one was able to put themselves in the shoes of a layman reader.

Still, readers will enjoy Polkinghorne's historical tales on how famous physicists of the early 20th-century were forced to drastically revise their views when simple experiments did not turn out the way they expected. I am familiar with this book and Cox and Forshaw's The Quantum Universe, and this book is better because it will leave you just as (badly) informed, but it is much shorter than Cox & Forshaw and lacks an annoying rhetorical device in their book.

After a productive academic career, Polkinghorne left physics in the late 1970s and became an Anglican priest. His Christian beliefs make absolutely no appearance in the book, and while he dedicates some space to opposing philosophical views on quantum reality, he points to other scientists, never himself.

At the end of the book, Polkinghorne tries to deflate "quantum hype", the use of new physics to pitch flim-flam. However, what he has in mind among some New Agers is that quantum theory supports ESP. In the years since its 2002 publication date, quantum theory has often been misused by self-help businessmen who claim quantum theory proves that one's thoughts influence the universe, so think positive for riches, but Polkinghorne didn't debunk this form of hype.

[Joseph Sverker · Rating 4 out of 5]

Well, this was a truly impressive work. Polkinghorne manages to explain quantum theory and much more I think. He packs so much of interest into this book that it is a miracle how it can be so short. It is also quite complex I would say (a complex subject though!) that I wonder if it should be called "introduction". That is not a comment against the clarity of view, but a comment on the depth that I think he manages to reach.

[Josh Friedlander · Rating 4 out of 5]

There's a perception of Quantum Mechanics as something mysterious and difficult, but it is actually a well-accepted part of the basic physics any undergraduate would study, and its philosophical mystery is encapsulated in one basic puzzle. Through several decades of what Dirac called "lots of first rate work done by second-rate minds", the concept has been experimentally confirmed in incredibly accurate ways. This Very Short Intro is pretty good, considering the philosophical approaches and containing very little (but not zero) maths. Below are my (lightly edited) notes.

The story begins with the "ultraviolet crisis" in statistical mechanics. Light was well understood by Maxwell's equation as an electromagnetic wave propagated in the luminiferous (ie "light-bearing" aether), solved with Partial Differential Equations. Except then you have black body radiation, which the theory predicted to be infinite(!!) at higher frequencies! Bohr realised that it made sense if you saw light as being emitted in quanta - really like a particle. But then is it a wave or a particle? Hold that thought.

Then with electrons you also have issues. Thompson imagined that you had a big positive charge studded with electrons, the plum-pudding model. But then they bombarded an atom with alpha-waves which bounced back! That made sense if you imagine that actually all the mass is concentrated in the centre, like a solar system. But then wait: why don't all the electrons crash into the centre? The answer is Pauli's exclusion principle, the electrons don't like to be in the same state or place (this is because they are fermions, unlike light particles (photons) which are bosons, which do like to cluster in one place, which is why we have lasers and also explains some of the conducting effects of crystals). In some sense not only is light (waves) actually a particle, but electrons (definitely a particle, right?) are in fact also waves!

Here you have the double-slit experiment: as Feynman said if you meditate on this you have the whole puzzle of QM. Fire a light beam at two slits and you have an interference pattern, because they are waves interfering with each other and on average hitting the centre between the two slits. But fire just one electron and it hits dead opposite the slit, so why do a cluster of them land in the middle? Well this is the wave-particle duality which we still don't have a good answer for, there is Copenhagen idea of complementarity (it is both, very Zen), the theory that electrons are particles that also have shadow waves of potential, Everitt's Multiple Worlds, a similar theory of multiple minds, plus various other theories. Talks a bit about the philosophical implications. Wheeler had this "delayed choice" Gedankenexperiment where you measure it after it's fired, so it changes path in mid-flight - trippy! Is it human minds measuring that affects things? What about cats or earthworms, what about computers?

There is a bit of the mathematics - Heisenberg used matrix algebra to solve QM, whereas Schrödinger used more conventional PDE but it comes out the same. Dirac theorised positrons, electrons are gaps that pop into existence in a sea of positive charge. Decoherence - the way it becomes macroscopic.

EPR asked what if two particles become quantum entangled, generated in such a way that examining the one will affect the other - can this information travel faster than the speed of light? Answer is yes! This is the concept of "action at a distance", accepted by Newton, made unnecessary by Maxwell and Einstein, but now revived.

[Randy Wilson · Rating 5 out of 5]

I came to this book because I read the, 'Rigors of Angels’ which made me read “Relativity, a very short introduction.” I found that book quite comprehensible which led me to this short introduction on quantum physics. Before reading ‘Rigors of Angels’ I had no idea what quantum physics meant. I just knew it was esoteric and different from classical physics but how or why was a complete mystery. After reading this introduction I have a much better handle on the key concepts and how they sit along side relativity and classical physics.

I will never acquire a deeper understanding of physics mostly because of the math which is way beyond me. However, the concepts of quantum physics are very attractive because they make the study of physics and all of scientific inquiry make sense in a different way for me. The key to science isn’t to know it is a study of nature, or the planet or the universe. It is the attempt to develop observations of the natural world that can give us better information about it. However, all those ideas are limited by the thinking of the people developing the observations. This fact alone makes it clear that given the phenomenal size, scope and interconnectedness of life on our planet and beyond, our ability to devise observations at the scope of Earth are impossible. We are never going to know that much about how the universe operates. The effort is still so important and useful but it is very limited. This fact is complimented by Heisenberg’s uncertainty principle which says that one can observe a particle or its motion but it can observe both at the same time. Reason won’t get us that far and it’s important we fully take that in and shed as much hubris as we can.

[Books and margaritas · Rating 3 out of 5]

While I love popular science books that focus on astrophysics, cosmology and quantum world, I was a bit disappointed with this book. Notwithstanding that the author himself is a brilliant physicist (and was a student of a legendary Paul Dirac), his writing was extremely dry.

Personally, I think the biggest problem with it is that the author couldn't decide on his target audience. It is doesn't go deep enough into all the "science" to satisfy the more knowledgeable readers, and it fails to entertain readers like me, who enjoy reading the same basic information, for the gazillionth time, as long as it is presented in a humourous and digestible manner. Yes, I like to be spoon fed when it comes to quantum mechanics, and no, because I am doing in on my free time, I don't want to read an introductory academic paper on this topic. And this is exactly what happened here - reading this book was a tedious task.

[Timo · Rating 4 out of 5]

The very short introduction to Quantum Theory by Polkinghorne gives an overview of the history of Quantum Theory and explains the basic phenomena with as little mathematics as possible. The historic part was especially interesting to me. Introductory university courses focusing a little more on that part could help students understand what’s going on on a slightly deeper level I think (as far as anyone can really „understand“ Quantum Theory). To me, it was very useful to revise the basics and gain (very little) more self-confidence in the field of Quantum Physics. A solid piece, recommendable to any physics students feeling lost when it comes to Quantum Physics.

[Anthony · Rating 5 out of 5]

As an introductory note, this is excellent. Really strikes a balance between the scientific endeavour and the resulting philosophy. Also has good insight into the personalities behind the development of the theories and experiments (the author's particular love for Dirac notwithstanding). Terrifc.

[Bumbles · Rating 3 out of 5]

The day I understand even rudimentary quantum theory, I wouldn’t know what to do with my self.

[Anna]

Hhhhh falling behind on reading is the worst my brain is mush

[flimpi · Rating 4 out of 5]

bissl reinfuchse und dann passt dät scho, andere reviews hän den oasch offne

[Arko · Rating 5 out of 5]

Very crisp and clear content. A must read for science lovers.

[J.D. Steens · Rating 4 out of 5]

Polkinghorne’s preface opens with this statement: “The discovery of modern quantum theory in the mid-1920s brought about the greatest revision in our thinking about the nature of the physical world since the days of Isaac Newton. What had been considered to be the arena of clear and determinate process was found to be, at its subatomic roots, cloudy and fitful in its behavior. Compared with this revolutionary change, the great discoveries of special and general relativity seem not much more than interesting variations on classical themes.”

For Polkinghorne, the quantum world is more than just small (where at the Planck scale “a row of dots looks like a solid line”). At the nucleus level, subatomic particles behave differently than in the deterministic universe of Newton and Einstein, where linear cause and effect relationships are clear. Rather, in the quantum world, there’s Heisenberg’s uncertainty and its “epistemological principle of ignorance” regarding position and momentum that lies at the core of reality. Polkinghorne writes of quantum logic that, as opposed to an Aristotelian true/false dynamic, includes a “maybe,” where what can be said about electrons can only be stated in probabilistic terms. In quantum mechanics, a particle can jump through barriers “provided it reaches the other side quickly enough to pay back energy within the necessary time limit. It is as if the particle had tunneled through the hill.” Per Feynman, we have virtual particles without physical mass that exist as intermediate particles, different than what exists initially or at the end of a process. Polkinghorne states that even Newtonian mechanisms exhibit quantum properties – when very small disturbances make “their future behavior beyond our power to predict accurately. These chaotic systems (as they are called) soon come to be sensitive to detail at the level of Heisenberg uncertainty or below.”

Polkinghorne writes that within a vacuum, the lowest energy state, there is still “an infinite collection of harmonious oscillation” with specific frequencies. Even in empty space, particles move (there’s “zero point motion”). A vacuum “is a humming hive of activity,” he says. “Fluctuations continually take place, in the course of which transient ‘particles’ appear and disappear. A quantum vacuum is more like a plenum than like empty space.” Finally, at the heart of the quantum world, Polkinghorne writes that there is a “deep-seated relationality” or correlation between two events where “entities that have interacted with each other remain mutually entangled, however far they may eventually separate spatially.” This, for Polkinghorne, means that at the smallest levels of matter and energy there’s more than pure atomism that is involved.

Polkinghorne closes with a chapter on “lessons and meanings.” His quantum world counters positivism with its self-imposed limitation on using only observational data. For him, the quantum world of electrons and photons, quarks and gluons are real, operating at very small scales. They don’t overturn classical theory but they make “intelligible great swathes of physical experience that otherwise would be opaque to us.” The quantum world is a relational reality that transcends atomism. And, he advises, the quantum world is anything but arbitrary. In fact, he argues that it accounts for the fundamental stability of atoms. While probabilistic and not deterministic, and while it operates in a “wraithlike” fashion, the quantum world has order and stability. And “random subatomic uncertainty is very different, indeed, from the exercise of the free will of an agent,” he says for those who attempt to use the meanings of quantum physics this way.

Polkinghorne draws heavily on the work of Dirac. He makes several references to “wave-like” and “particle-like,” but the reader is left with the impression of a third subatomic property that is neither a wave nor particle. Here and there, the author leaves his lay readers behind who, lacking in the requisite background, bump into some fairly thick stuff. Yet, this book, while short, is a lucid description of a complex subject.

[Kyle · Rating 4 out of 5]

It is what should have happened a few centuries after Newton's theory of everything became the dominant scientific framework for how things work that classical physicists start dreaming up improbable situations based more on pre-Socratic philosophy than evidence-based research. This is not a slam against the many men (are their any women quantum theorists? - not in this book) who developed a way to explain the very fast and the incredibly small. In explaining the history of quantum theory, Polkinghorne does not let the numbers get in the way, saving the formulae for the Mathematical appendix, but in their place are what, words? His admiration for one of the founding fathers' plainspokenness belies the most intriguing aspect of quantum physics, they are all dreamers who can see beyond the angels dancing on a pin's head and find ways of telling their stories to others. Of course they use math, it is more convincing that way; but really, if an experiment fails to produce expected results, they can just change a fraction or something, right? Even Einstein gets caught up in the fudging-numbers game. But what impresses me most are the images the physicists use: cats in boxes, many worlds, an electron being fired from a cannon etc. Seems a bit bizarre, in the last chapters, to read how some things are not possible with quantum theory (like telepathy or time travel) when a more open-minded approach would be "has not been proved yet."

[Oveis · Rating 5 out of 5]

با این‌که سعی نویسنده در همهٔ قسمت‌های کتاب بر این بوده که از آوردن هر رابطهٔ ریاضی‌ای خودداری کنه و مفاهیم رو تا حد امکان ساده‌سازی کنه، اما با این حال برای کسی که فیزیک نخونده باشه کنار اومدن با کتاب و به اتمام رسوندنش بسیار کار سختی خواهد بود احتمالاً (با این‌که کتاب حجیمی هم نیست).
اما برای کسانی که فیزیک می‌دونن، این کتاب لذتی براشون خواهد داشت که در کمتر کتابی می‌تونن شبیه اون رو پیدا کنن.
خصوصاً قسمت‌هایی از کتاب که آزمایش دوشکاف رو توضیح میداد یا قسمت "منطق کوانتومی"ـش. یا قسمتی که نظرات مختلف رو در مورد "مسئلهٔ اندازه‌گیری" نقد و بررسی می‌کرد (که واقعاً برای من لذت بخش بود)
فایده‌ای که این کتاب برای غیرفیزیک‌ها می‌تونه داشته باشه اینه که اون‌ها رو متوجه این واقعیت کنه که مکانیک کوانتومی چقدر با اون نگرش عینیت‌گرایی ماها در تضاد و تعارض هستش و این‌که می‌تونن متوجه بشن که راجع به مکانیک کوانتومی به همین راحتی‌ها نمیشه اظهار نظر کرد...

[Remedy Loame · Rating 3 out of 5]

Very accessible, took a little chewing sometimes (probably because my physics background is minimal) but there are some nice slices of science history to be had. I'm sure there are plenty of more substantial books on quantum theory out there, but this was a nice sampling of concepts.

Nitpick: Used the words "fitful" and "cloudy" too much.

[Gendou · Rating 4 out of 5]

A short overview which wastes time in the mire of philosophy and metaphysics.
Sadly avoids mathematics, which is typical for a popular science book.
Still, quite informative for the newcomer and good review for those already familiar with the topics.