What Is Quantum Mechanics Good for?

Physicist James Kakalios, author of The Amazing Story of Quantum Mechanics, wants people to know what quantum physics has done for them lately--and why it shouldn't take the rap for New Age self-realization hokum such as The Secret















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And just as Schrödinger couldn't have had any idea about what his equation would be used for, the same could be said of the laser, which now allows us to have CDs and DVDs and a lot of other things.
The same goes for the transistor. It was first developed to amplify radio signals, and you had transistor radios that replaced the vacuum tubes that were being used. Now they are also used as logic elements, 1s and 0s. If you apply a voltage to a transistor you can basically open or close a gate and allow electrons to flow through or make it very difficult for electrons to flow. And so you have two different current states, high and low, that you can call a 1 or a 0. You can combine them in clever ways to do logic operations with the 1s and 0s. You can encode information. You can develop a language of the 1s and 0s and manipulate them that way.

And again, I don't think that was the first thought of the people that developed the transistor. Look at all the things that it has brought out. There are probably more transistors in a standard hospital than there are stars in the Milky Way Galaxy, when you think about all the computers and all the electronic devices that we use just for medical applications. So it really has transformed life in a very profound way.

The real superheroes of science are a small handful of people who knew they were changing physics, but I don't think they recognized that they were also changing the future.

One of the ways you keep this book lively and accessible is to use anecdotes from early science fiction. How well have those predictions held up?
The main problem is that they believed that there was going to be a revolution in energy, which would lead to jet packs, death rays and flying cars. But what we got was a revolution in information. This information age, of course, came about because of semiconductors and solid-state physics, which were enabled by quantum mechanics.

A lot of these things go back to transistors and semiconductors. Is that in your view the biggest fundamental leap that quantum mechanics allowed us to make?
More than that, even. By discerning what were the fundamental rules that govern how atoms interact with each other and how they interact with light, you also have now a fundamental understanding of chemistry. There is a reason why the atoms are arranged the way they are in the periodic table of the elements, and it comes out naturally from the Schrödinger equation when you add in the Pauli exclusion principle. There is a really deep appreciation for why the world is the way it is.

Can you imagine living in a world before quantum mechanics?
We take all these things for granted. It's like the Louis C. K. YouTube clip—everything is amazing and nobody is happy.

"Quantum" is thrown around a lot as a label for things we don't understand, and we often lump a number of phenomena into the vague category of "quantum weirdness". Is that something that you'd like to see dissipate?
I would. It's used too much as a catchall. Proposing weird and counterintuitive ideas to explain observations, developing the consequences of these ideas and testing them further, and then, if they conform with reality, accepting them is not unique to quantum mechanics. It's what we call physics.

Also, because it has a reputation for weirdness, quantum mechanics is used too much as a justification for things that have nothing to do with quantum mechanics. There is an expression, "quantum woo," where people take a personal philosophy, such as the power of positive thinking or let a smile be your umbrella, and somehow affix quantum mechanics to it to try to make it sound scientific.

And make a lot of money doing so.
Yeah. It kind of seems to me to be at the same level as using mathematical knot theory or topology to justify crossing your fingers when you're making a wish. It has about as much relevance and justification.



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  1. 1. JamesDavis 08:41 AM 11/2/10

    It seems like we should develop Quantum Mechanics into an addiction. That would be an addiction we all can live with comfortably.

    Great article by the way.

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  2. 2. Carlos Solrac 06:15 PM 11/2/10

    "[But] it is also responsible for the technological advances that make modern life possible. Without quantum mechanics there would be no transistor, and hence no personal computer; no laser, and hence no Blu-ray players." This statement, which is already a truism, should be backed with some explanation on how quantum theory is applied in technology. That would merit a Nobel in physics!
    The sour truth about quantum is told by Roger Penrose in "The Road To Reality", but it will take a while for scientist to digest it.
    Now, the day superluminal communication is realized and quantum computers work, well, that day we should open the champagne. Until then we should refrain from ridiculous statements.

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  3. 3. verdai 06:32 PM 11/2/10

    Regardless of any theater, light emitting energies cannot be measured
    really.

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  4. 4. verdai 06:33 PM 11/2/10

    Regardless of any theater, light emitting energies cannot be measured
    really.

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  5. 5. bongobimbo 07:09 PM 11/2/10

    An article to be enjoyed. Anything that exposes New Age fantasies is worth introducing to our more gullible friends.

    I'm just a general reader, although physics is one of my favorite subjects. I gave up majoring in it as an undergrad, switched to Linguistics, and some years later did my grad work in Medieval Studies. That's not so far fetched as you'd think, when you consider the amazing progress in mechanical engineering, optics and mathematics in the later Middle Ages from East Asia through India to Western Europe.

    When I was about 22, not long out of college, I read a new book by physicist Banesh Hoffman, THE STRANGE STORY OF THE QUANTUM. Forget the romantic title. It's very well-written, a great introduction. I admired Hoffman's book so much I went through 3 copies--since I kept lending it to friends who'd forget to return it.

    Of course it's been outdated for years. I've been trying to keep up with every area of science in SCIAM, sometimes find the quantum physics features over my head, so am looking forward to this new Kakalios book! Thanks for publishing a very readable review and commentary.

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  6. 6. jtdwyer 12:55 AM 11/3/10

    The article states:
    "...that light is a photon; that matter has a wavelength nature associated with its motion; and that everything, light and matter, has an intrinsic angular momentum or spin that can only have discrete values..."

    Perhaps I'm wrong, but I think it's more clear and precise to state that:
    - matter, in addition to its stationary particle state, has a wave state that produces all of its motion through self-propagation
    - light has a particle state that can be detected through absorption of its wave state momentum
    - both wave and particle state manifestations exhibit an intrinsic angular momentum or spin characteristic property that can only have discrete values

    Nicely done article, although I think the transistor was invented in Texas to make compact calculators but first mass produced in Japan to make inexpensive portable radios.

    More than the few physicists that have produced breakthrough fundamental discoveries, there's been an enormous amount of extremely creative work done by countless unrecognized engineers and programmers to produce the highly advanced critical technology that presumedly allows the more productive use of our valuable time.

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  7. 7. bucketofsquid 09:59 AM 11/4/10

    If I remember correctly, the guy that invented the transistor died pennyless, of a disease that he could not afford the treatment for. Isn't capitalism wonderful?

    Nice review and I will be aquiring the book when I can afford to.

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  8. 8. C 09:29 AM 11/5/10

    Carlos,
    Do you 1) not accept that the laser and the transistor work on quantum mechanical principles? Or do you 2) not accept that a detailed understanding of quantum mechanics made these devices possible?
    If 1), you should take a class on these devices. If 2), I'll grant you that quantum effects were observed before they were understood. It is possible to build technology without fully understanding it. However, it is extremely difficult to improve technology without understanding it. You would not have a DVD player if the only lasers out there were 1960s ruby lasers. Quantum mechanics is used when designing the structure and materials of lasers and transistors. As far as Penrose goes, I have his book and I have no idea what you mean by the "sour truth" about quantum mechanics. The fact that QM (like all theories) has limitations doesn't make it useless, and Penrose never suggests otherwise.

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  9. 9. Carlos Solrac 10:32 PM 11/5/10

    C, Q: Do you 1) not accept that the laser and the transistor work on quantum mechanical principles? Or do you 2) not accept that a detailed understanding of quantum mechanics made these devices possible?
    If 1), you should take a class on these devices. If 2), I'll grant you that quantum effects were observed before they were understood. It is possible to build technology without fully understanding it. However, it is extremely difficult to improve technology without understanding it.

    Nobody in Bell's Lab (which invented the transistor) knew a thing about Quantum Mechanics! After the invention was done theoretical physicists created "Solid State" curriculum to "adapt" the very adaptable Quantum Theory to the new facts. As for the "laser" Quantum theorists
    predicted the "maser" and wasted a lot of taxpayers money. Meanwhile technologists developed the laser into what is today's products.

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  10. 10. jtdwyer in reply to Carlos Solrac 11:06 PM 11/5/10

    Generally well put - thanks.

    My vague recollection was that Texas Instruments invented the transistor, so I consulted wikipedia. It states that Physicist Julius Edgar Lilienfeld filed the first patent for a transistor in Canada in 1925. Bell Labs patented the the transistor in the U.S. in 1947. The first silicon transistor was produced by Texas Instruments in 1954. It's worth a read.

    I think though that you are essentially correct in asserting that quantum theory has had little if anything to do with technological developments - most often just the opposite.

    In regards to VLSI electronics, including computer chips, one predicted quantum effect that has come into play is the tunneling of electrons through silicon substrate. I'm not a processor designer and can't say if this phenomena is employed in the design of processors, but it is the limiting factor in circuit miniaturization, as device electron leakage produces processing errors and device EM leakage producing heating and power losses.

    I've been reading that quantum computing is just around the corner for decades, it seems...

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  11. 11. Thim 11:27 AM 11/6/10

    Instantaneous information transport is possible even in classical mechanics. In car engines the cam shaft is doing that by synchronizing valves instantaneously. Of course, the cam shaft has to be made of very stiff material. Steel will be good but not good enough. Silicon would be better. Some physicists will say that instantaneous information transfer would violate special relativity. Special relativity is known to be incompatible with quantum mechanics as well as with classical physics. So let's forget about special relativity, see Sciam March 2009 issue.

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  12. 12. rrkarnik 10:44 PM 11/7/10

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  13. 13. rrkarnik 10:47 PM 11/7/10

    Quantum Mechanics as understood today is a device of stupid scientists who cannot think beyond Differential Calculus posted by Newton more than 300 years ago.

    Mathemaics exists beyond this. Numbering Differential Calculus at level four, we go right upto level twelve. But you do not have to go that high. Even at level five, just one above what these idiots consider upper limit, you can see that “Uncertainty Principle” is an illusion created by limitations of Differential Calculus.

    With this level operations you can always re-format any Diffraction experiment into variations in dielectric value in space so that initial radiation pattern of photons gets changed into the diffraction pattern with sharp trajectories of every one of the photons exactly defined so that the location and momentum (also velocity) of the photon can be exactly computed.

    What did you say ‘what about matter waves?’ Only an idiot can think of matter waves as scalar, as do these Qantum fans. Matter is all electromagnetic, else it would not obey Lorentz Transformation (read Einstein’s Relativity Theory), which is just Maxwell’s equations in a different format. So go ahead and laud these Quantum idiots who do not even know that. After all Einstein was correct. “GOD does not play dice.”

    Dr. R. R. Karnik
    ravi@karnik.com

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  14. 14. Thim 04:20 AM 11/8/10

    rrkarnik:
    Quantum Mechanics explains why electrons emit microwaves from Gunn effect semiconductors such as gallium arsenide. Why the photoelectric effect is correct as Albert Einstein has said in 1905. Special relativity, however, is wrong as the Lorentz transformation equations are illogical and as Michelson and his student Gale have shown by measuring the earths rotation using light beams. Einstein was a good scientists but relativity theory is wrong. The Nobel Committee knew that and therefore gave Einstein the Price for Quantum effects. The Schroedinger equation is the starting equation in all textbooks for QM.

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  15. 15. rrkarnik in reply to Thim 09:07 AM 11/8/10

    Dear Thim

    First I agree with you on Special Relativity Theory being wrong. You do not seem to know General Relativity Theory, but it is also wrong. I will welcome criticism even on this.

    Lorentz’s work is just re-formatting of Maxwell’s Theory. If you think that Maxwell is wrong then I do not know what to think of you, being an Electrical Engineer and having used his theory for everything.

    What you are praising in arsenide excited states and photo electric effects is the Diffraction Phenomenon, in which exact motions, that is exact locations and momentum (velocity) of photons and electrons are not even allowed, in Quantum Mechanics, due to stupid “Uncertainty Principle”. So explanation is out of question, only some “Thumb Rule guesses are stated”, which may or may not be correct, which is all that Quantum Mechanics is good for, which is my point. We need Mathematics higher than Differential Calculus, which can solve an infinite series of Differential Expressions in one go, which is my point. It can be demonstrated that, with Calculus at level four, these levels can go up to twelve.

    The very fact that QM starts with Schroedinger equation which treats matter waves as Scalar is proof itself that QM is no good.

    Dr. R. R. Karnik
    ravi@karnik.com

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  16. 16. Thim 09:24 AM 11/9/10

    Dear RRKARNIK:

    well, Maxwell's equation work quite well but Feynman had tried to modify them as they fail in certain applications. As a consequence of this Quantum Electrodynamics have been invented by Feynman. I am still using Maxwell's equations successfully.
    Solutions of Schroedinger's equation predict for electrons particle-waves in semiconductors thereby forming conduction band valleys in which electrons experience differential negative conductance. The consequence of this are microwaves emitted from those semiconductors such as GaAs and InP which have been measured.
    So the Schroedinger equation cannot be so bad as you are saying.
    The Lorentz Transformations are much worse and illogical but the inventor of those did not recognize that and rather called Quantum Mechanics "Spooky Actions" or thought that God does not play dice and more similar nonsense.

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  17. 17. Thim in reply to jtdwyer 09:29 AM 11/9/10

    jtdwyer's:
    how can you say: "Nobody at Bell Labs used QM". I did
    use them and found that due to quantum mechanical laws gallium arsenide bulk amplifiers worked well at microwave frequencies so those patended devices had been used by the United State Defense Department!

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  18. 18. rrkarnik 12:27 AM 11/10/10


    Dear Thim

    I do not know what Feynman did in Electrodynamics, I have high regards for him, but I too have a version of Maxwell’s Equations that give Vector matter waves just like Electromagnetic waves and can be mapped exactly, responding to variations in dielectric values, which what this Gravity business is.

    I am sure that Feynman’s version does not give exact location and momentum of photons at every point in its path from initial emission to final absorption. He is not that bad.

    This prediction business is the bane of QM, as it prevents working out exact solutions, which can be verified, and generates wide speculations, which we call power without responsibility. Yes, you do hit the targets once in a while but remember that 9 out of 10 semiconductor wafer manufacturers went broke. So there is an exact solution that is blocked out by these stupid scalar concepts of matter waves. Making money is not development of science, finding exact solutions is.

    Deriving Lorentz Transformation without the rest of Electrodynamics is stupid and I am all with you for condemning Einstein for that, but working with retarded vector potentials is satisfying and when you do it on a moving platform like a train, these transformations are very handy. The probability business in QM is merely using the properties of binomial coefficients, the numbers are not even complex. That is how businessmen make money, they have highly paid executives just doing that. But that is not science, getting exact solutions is. Unless this “Uncertainty Principle” is purged QM will never become Science. I do not believe in GOD , but universe does not run on throw of dice and what you have stated about it, itself is a condemnation of QM.

    Remember that Physics is an exact science. Electron motions inside a solid can be modeled exactly. In fact I de-bunk General Relativity by computing the product of momentum and velocity of each of these electrons and claim that this is attracted in gravity and when this is reduces as when tensile stress is applied, the downward force in gravity gets reduced, meaning levitation of tensile stress volume, which effect does not exist in General Relativity. This QM is thoroughly useless for this proof.

    Another application is the so called “Spin Interactions”. With scalar matter waves their polarization is not possible, which forecloses computation of these spin effects using polarization. They have invented the non-existent “Spinor”, and instead of tracking the variations in diffraction patterns, due to polarization and measuring and converting them into attractive and repulsive forces, just guessed backwards from some average measurements what they should be. Einstein failed to develop his Unified Field Theory because, stupid as he was, he knew from personal experience that stupidity was infinite, he actually, like you, believed in QM theory, which using scalar matter waves did not give him the right directions.

    So go ahead and stick to QM, you are not going to go forward in science that way.


    Dr. R. R. Karnik
    ravi@karnik.com

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  19. 19. Thim 07:41 AM 11/10/10

    I agree with you, RR Karnik, that QM is a tool, but it is a useful tool. It explains why electrons behave as they do in semiconductors. Ohm's law could not do that. Ohm's law is useful to explain currents in copper wires. Approximately. Not precise. But useful. QM is much better. How would you explain conduction and valence bands in semiconductors? How would you explain why LED's and LASER diodes work? However, no theory is perfect.

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  20. 20. rrkarnik 09:25 PM 11/10/10

    Dear Thim
    All that you mention, seemingly impossible can be done, exactly and even the momentum and velocity of all these electrons can be computed, which according to QM is impossible. Of course no theory can ever be perfect, that is the first principle of “advaita brahma”, which is essence of basic science.
    If superstitions, called “avidyaa” in Sanskrit, were not useful and did not explain what the believers want they will simply disappear. In “advaita brahma” even concept og GOD is “avidyaa”.
    My grouse with both Relativity and QM is that they block the future scientific free thinking, which is a greater loss to science than what the petty successes gain. With these two theories the mind of scientists is no longer open. They do not even publish your treatises if you contradict these theories.
    That is all my point. QM does more bad than good.
    Dr. R. R. Karnik
    ravi@karnik.com

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  21. 21. Momus 06:26 PM 11/24/10

    I hope the book is better than this article.

    Why use meaningless analogies, using totally factitious situations like the analogy with auditorium and a balcony above. It explains nothing about laser, nothing about how/why they work. And it gives less intuition then some straight descriptions.

    Then, so much space used to convince us about obvious, that original inventors often don't know the future use of invention. You mean like the original inventors of the wheel didn't foresee it's use in Space Shuttle or Wheel of Fortune show? What a shock...

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  22. 22. mastrostudio in reply to jtdwyer 06:12 AM 1/29/11

    Well stated. I view everything as a kind of duality between balance and imbalance. Any quantum state is a state of balance. Any phenomena discribed or percieved as a wave is the propagation of balance as a function of time. The former is percieved in the moment, the later over a time period.

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  23. 23. mastrostudio in reply to C 06:24 AM 1/29/11

    The history of the artificial is built on chance observation and discoveries. We put rock on rock and notice some methods of doing that are more stable than others. Today we build massive skyscrapers yet we still really do not understand what gravity is. We build clocks that are ever more precise and sophisticated yet we still do not really understand what time is.

    We build mathematical models that enable us to predict cause-effect reliably. Our growth in understanding and science in general is a growth in understanding "how" things behave in the natural world. Science doesn't really involve itself with "why".

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What Is Quantum Mechanics Good for?

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