Summer School 2010.1: Quantum Physics

The onset of summer is no excuse to stop learning. In this year’s session, we will address Quantum Physics. Be here each Monday morning through July and August for a new lesson in the nine part series, covering graduate level physics concepts with grade school math, or no math at all. The first lesson: Classical Thinking: Why Does It Fail? Thanks go out to my proofreaders: Gord Haverland, Maurice Hilarius, Bonnie Hogg, Claire MacDonald, Rob MacDonald, Neil Pritchard and Anthony Stauffer. Thanks also go to Stacey Keeler, the artist who created the spiffy new category icon you see here. Complete syllabus below.

Course Syllabus: Physics 142 – Quantum Physics


Times: Every Monday through July and August

Capacity: Unlimited


  • At least average intelligence. It is safe to assume all Bureau 42 exceed this prerequisite.
  • Grade school level math. The most complicated math in the series is this: “if a times b is less than 6, and we measure a to be 2, then b must be less than 3.” If you can follow that, you’ll be fine.
  • The ability to view PDF documents. If you do not have such an ability already, there are numerous effective free packages for viewing them available online, include Adobe Acrobat Reader, xpdf, kpdf, GhostView, and more, according to taste and operating system. Adobe created the Portable Document Format, so their reader is a safe bet.
  • An interest in learning.


50 replies on “Summer School 2010.1: Quantum Physics”

    • Ooops, this is actually a chrome developer channel bug not your PDF (Chrome’s new integrated pdf reader). Ignore pls

  1. Really enjoyed this….you mentioned more questions than answers will happen toward the end….I guess I’m already there! Looking forward to the remainder of the series!

  2. I had years of stupid teachers spouting the common mantras of “things” taken to be fact, simply on the basis of everyone else saying it was fact.

    It’s about time you came up to speed on teaching the subject instead of spouting ideas that were affirmatively sunk decades ago.

    This is crap and very outdated:

    1 Some Preliminary Words
    One consequence of Einstein’s relativity causes serious problems for most classi-
    cal pictures of the subatomic world. Exactly how this consequence comes about
    is best covered in a session on relativity, and therefore will not be covered here.
    All we need is the consequence itself so that we can apply it: Nothing, not
    even information, can travel faster than the speed of light.

    Magnetic fields and Pulsars faster than light.

    Scientists have been plagued by Einstein’s theories which state nothing can travel faster than light. But over the past decade or so, we have seen a new branch of physics theorized, one which might give Einstein cause for pause. It’s called Superluminal Electromagnetic Field / Wave Propagation, which is basically a form of faster than light relativity. Experiments have been conducted by several scientists which involve light and radio sources traveling at speeds well in excess of the speed of light.

    Faster-than-light pulsar radio waves found

    Faster-than-light communication

    • From your Scientific American link:

      This method of breaching the speed barrier might seem like cheating–after all, no material object is breaching the barrier. But electromagnetically it doesn’t matter. Whatever the origin of the pulse in a wire, it involves the motion of electric charge and emits electromagnetic radiation. The radiation propagates outward at the speed of light, but is forever shaped by the speed of whatever generated it

      In other words, nothing is travelling faster than light, but they can make things look like they do.

      The article compares it to the spot of a flashlight on the moon. Again, the physical objects are restricted to lightspeed; a non-physical object being regarded as having physical character is the bit that would appear to violate the light speed limit. Again, relativity is not violated.

      Your link makes a point of saying that the pulses do not contain information, and don’t violate relativity. Looking at the source paper reported on in January, it is incomplete. It states that some pulses arrive faster than others, but doesn’t calculate their individual speed. I also note that, some six months later, it’s still unfinished; none of the references are coming through. I’m wondering why that is.

      For the last link, that’s entanglement, or “spooky action at a distance,” which is a remarkably special case, and still needs to be understood. That’s an area which has been under scrutiny for a decade, and only works when there was a point at which the involved particles could have exchanged information at subluminal velocities. It appears that the regions of quantum probability are extended over space; the regions will be introduced in lesson six.

      • Ah, I was wondering if “spooky action” would come up. Your explanation does a great job covering information transfer as a physical action. Which of course caused me to think of spooky action. For now I’m willing to leave spooky action out since IMHO it is breaking the laws of relativity regarding information transfer, but we’re not sure exactly why.

        Having learned this stuff a long time ago (replete with tricky math), I look forward to seeing these concepts presented in basic terms.

      • Naaaaaaaaaaaaaaa All these dopey nay sayers – “Nothing, not
        even information, can travel faster than the speed of light.”

        That is garbage.

        To be a pedantic shit – the qualification was “NOTHING” can travel faster than light.

        Well light can be stopped completely. Light can be teleported. Light can be slowed, and light can have a fire cracker rammed up it’s ring and be sent at a speed that is WAYYYYYYY faster than light.

        Take the issue of my creation of the universe – Ok there are galaxies receding at almost the speed of light – say 90% of the speed of light. We will call that galaxy A.

        What happens when that galaxy heads towards another galaxy – that is approaching us at near or 90% of the speed of light? We will call that galaxy B.

        So if one was on Galaxy A, the relative approach speed of Galaxy B, would be 1.8 x light speed.

        And the light it’s self coming from Galaxy B to Galaxy A – when telescoped from Galaxy A, would be travelling at 2.8 x the speed of light.

        To toss in the old light speed it’s self – When it’s entering a gravitational field, it accelerates, and as it leaves, it decellerates.

        All this excessive gripping of the “Holy Mantra of Einstein” and then sounding clever because “I am a clever guy or guyette who can quote the cleverestus guy, makes me cleverer than you” dribble is just bullshit.

        The speed of light in a vacuum is only a defined speed to cross a distance., the speed is not the issue, the belief that it’s the limitation, is the limitation.

        As I said before the big bang, “Well there is your problem”.

        • Well, I’m convinced.

          No, silly, I’m not convinced that you’re right, I’m convinced you’re a troll. I wasn’t sure after that first message, but I guess you decided we’re pretty new at this “spot the troll” game and wanted to make sure we caught on. Appreciate the thought, but we’d have been just fine without the followup, thanks.

          Remember, folks: do not feed the trolls!

        • So if one was on Galaxy A, the relative approach speed of Galaxy B, would be 1.8 x light speed.

          No, it would not. Please understand, people don’t accept Einstein’s physics readily because they have tremendous respect for the man. People have tremendous respect for the man because his ideas explained otherwise inexplicable experimental results to fantastic degrees of accuracy, including predictions he made about how to add velocities in the manner you are describing. (In this case, 0.9c+0.9c does not equal 1.8c, it equals 0.994475c, as verified by multiple experiments.) In fact, if you read the text of the links you provided earlier, you’ll see that the researchers make a point of saying that their results are consistent with relativity.

          The exact manner in which these velocities must be added will be part of Summer School in 2013.

          • It’s totally wrong.

            If I am in Galaxy A, and Galaxy B – we are hurtling together, then the approach speed is 1.8 x light speed. Due to the speed rate of approach, then you would not see Galaxy B coming.

            The “speed of light” from point A to point B in a vacuum is only relative to the position of and direction of the observer.

      • No I just like the art work – and I hate [content which was unusually oversimplified and exaggerated, even for bigotry, deleted by site administrator.]

        • And with this, Jahm Mitt, you are on notice. Intelligent debate and discourse will always be welcome on this site. Racist and hateful comments of this nature will not. A repeat occurrence will result in the deletion of your account.

          • I am not on notice – and I will call you on your bullshit.

            Christianity – like every other cult – [snip repeat offense accusing an atheist of operating under church programming]

  3. So far, I am very interested. I am glad that my precalculus need not be strained! Thank you for taking the time to do this for everyone.

  4. Great reading. Thanks for making this accessible to us mathaphobes. On the statement: Nonetheless, information does get exchanged between particles, and yet violations of energy conservation have never been observed in an experiment. This
    seems to be a logical inconsistency that will need to be sorted out.

    -Is it reasonable to suggest that the process of energy transmission or conversion uses some amount of energy, thus keeping things in check?
    -Upon your reply I expect to wish I had thought it all out more clearly.

    • That would be reasonable to assume, but that’s not what follows from experiment. The answer will be introduced at the end of lesson three (July 19) and discussed in detail during lesson four (July 26).

  5. Thank you for this. It’s a rather ambitious project to try to keep this stuff both reasonably simple and stimulating but your first article is looking very promising!

    I’m hoping this will serve as a gentle introduction to some of the weirder parts of physics for my friends. I’m looking forward to the next edition.

    Good luck!

    Think of a particle radiating energy in order to transmit the information regarding its position. It may receive some energy back from other particles doing the same thing but what are the chances of the incoming energy exactly matching the outgoing energy without the particles specifically targeting each other?

    Alternatively, consider a lone particle separated infinitely from other particles. It would be emitting information regarding its position and receiving none from other particles. The question is: where does the energy to emit the information come from?

    I’m sorry if this doesn’t help but you may find thinking about what you mean by ‘use’ will clarify matters. Do you mean ‘destroy’? If you do then energy would not be conserved and this would not solve the problem.

    • I would think the Heisenberg uncertainty principle covers this. Basically particles don’t “advertise” their position. Correctly, you state that that takes energy. But the energy used to determine a particles position comes from the observation itself, which of course affects the particle as well. So you can’t know the position of a subatomic particle without altering is position, which is where the energy for the information exchange would come from.

  6. Waiting on EEStor

    The quantum question of the summer of 2010 is: Will EEStor do the deed? They are building a factory down in Texas to build super capacitors to power all-electric cars. If I go down to Radio Shack and buy a ceramic capacitor, its permittivity (the ability to store power as an electric field) will be around 30 f/m. EEStor claims their super special barium titanate material come in at 19,000 f/m and others have claimed one million f/m at cryogenic temperatures for their secret materials.

    If the EEStor factory can really churn these babies out, they will change the world. But, the company has been very secretive and has never produced samples for independent testing.

    Their claim is that quantum physic allows certain materials to form super electron orbits of enormous size. These orbits can be torqued by external fields to store energy. I certainly do not remember enough quantum physics to say aye or nay. So I might as well take this course while we wait for the world to change.

    • Yeah, this sort of thing crops up from time to time. I’ve seen enough of them in the last 10 years to more or less ignore them until somebody produces a sample for somebody else to test. OTOH, according to the Wikipedia article they describe the process in detail in their patent application, which means somebody should be able to reproduce it.

      (I don’t know how patents work in terms of allowing other people to verify the results independently, though. If Sally Scientist follows the procedure in the patent purely to study the material, does that violate the patent? What if she can’t make it work — does that invalidate the patent, or just get her sued?)

      • Yes, that is why everybody is just waiting them out. They should be soaring or crash-and-burn by Fall.

        You could build their patent for testing but the effort would cost millions and you could not make your money back.

        The trick is to let them spend the money (now estimated at 1.2 billion $US). If it works, then you develop a related technology on the cheap that is just different enough to patent yourself.

        The minute we hear that EEStor is shipping product the race is on.

    • Secret Ingredient

      The secret ingredient for the one million f/m cryogenic super caps are compounds called highly conjugated hydrocarbons. These molecules feature long chains with alienating single and double carbon bonds.

      What I will be looking for in this course is any hint as to why these compounds should show super high permittivity. Also why, at cryogenic temperatures they are both excellent insulators and have high permittivity when most high permittivity materials are very poor insulators.

      If this stuff works, then there are millions to be made.

    • As Pure as the Driven Snow

      One reason the high-permittivity materials are hard to design with is that they must be extremely pure to work. The EEStor Barium Titinate must be pure to 300 parts per billion to meet its specifications. Conventional manufacturing techniques do not produce this level of purity, so the commonly available materials do not show the high permittivity effect at all. Modern semiconductor fabrication processes can be used to produce this level of purity, so the time is right.

      The quantum questions are: Why is this effect so easily poisoned? What elements are the culprits in this classic detective case? Is this effect something like doping in semiconductors?

    • Do Not Reverse Polarity

      The high-permittivity materials have been described as member of a class of materials named after their first commercially successful member, memresistors. These materials have two state variables; one is a electrical quality (like resistance or capacitance); and the second controls the first but is not controlled by it.

      This is very like having a resistance box with a knob on the front. You set the resistance by turning the knob, but nothing you do to the resistance terminals can turn the knob. The effect works only one way.

      Memresistors are currently being used for electrical programmed semi-permanent memory chips. You can set each tiny resistor high or low and it stays that way for about 10 years.

      In this argument the high-permittivity materials are memcaps. You must go through a process to program them to high capacitance during manufacturing (usually involving temperature and high voltage) and they stay that way unless reprogrammed.

      The programming process is always symmetric and in the interesting cases extremely non-linear. The EEStor units are programmed at about 140 C and 4000 volts DC. The permittivity goes from about 40 to over 19,000 f/m.

      The quantum questions are then : is it useful to call these devices memcaps? What are you doing when you program them? What happens if they accidentally deprogram? Kaboom?

  7. thanks a lot for this, it’s a very engaging and easy read.

    i too had problems with high-school chemistry because the classical atomic model just did not make sense to me at the time — i kept imagining the positive-charged protons pushing each other appart and i thought, well this “model” is wrong. i couldn’t accept that, although the model doesn’t make sense from the point of view of describing how atoms work internally, it was still useful because clearly the model is accurate at the molecular level and is used all the time by chemists and molecular biologists.

    i guess i would have had a better time of high-school chem if my teacher had said to me “yes, this model is wrong, but that doesn’t mean it doesn’t work in explaining how you can mix chemicals….”. or maybe if i had more insight myself at 14, i could have come to the same conclusion. oh well. i think i am starting to get it now, 20 years later :)

    • Yeah, physics is almost entirely approximations! But many of those are really useful, so even if they’re “wrong” (i.e. not 100% correct) they can still be used a lot.

      The “planetary orbit” model of the atom breaks down pretty quickly, as it turns out, but it’s still a very handy way to think about what’s going on. We use a lot of models like that on a regular basis. Works great as long as we keep in mind their limits.

      As an aside, the real “orbitals” look more like a bunch of balloons tied together at the knots, actually. Which is entirely unhelpful when talking about the periodic table and trying to visualize inner vs outer electrons — but it makes it a lot easier to see why a water molecule is bent, for example. (Some of the electrons in the oxygen atom are used to connect to the hydrogen atoms, but a couple are left over and “stick out” on the opposite side from the balloons. That bends the hydrogen around a little.) So we typically use the approximations that are most convenient. (Too bad your chem teacher didn’t mention that; probably didn’t want to confuse you, ironically…)

      The upshot: sometimes you really can assume the cow is spherical. :)

  8. sorry double-post… :(

    regarding transmittion of “information”: i shall have to spend some time contemplating what information is, and why particles should be transmitting information about their possition, as if they were somehow sentient enough to produce and consume these abstractions. otherwise i’m hitting another conceptual wall here and having trouble matching the theories with whatever the reality could be.

    i guess i might best get along by just considering “information” to be another form which energy can take? i.e. when you speak of a proton transmitting “informaton about it’s position”, and an electron “recieving the information”, it’s really just the proton radiating energy (predominantly of the electromagnetic kind) and the electron reacting to that? or does this have to do with the application of theories of information entropy to the conservation of energy?

    i also have trouble with the “big-bang”. just because all galaxies have an observered red-shift best explained by the theory that they are all receeding from each other, does not necessary mean we can extrapolate that recession all the way back to having all galaxies everywhere occupying the same point. something could be pulling them apart instead, or maybe what we observe is just a (very large) global anomoly in an otherwise stable universe (and i’m not thinking even of multiple “universes”, oxymoron that it may be)? but here my problem is more with cosmology than with quantam mechanics, so it’s probably off-topic :)

    • I think by “information” we usually just mean any sort of interaction. It’s almost a metaphor. When two electrons repel each other, each electron needs to “know” the other is there so that it “knows” which way to go. In other words, each needs to apply a force to the other in order for them to repel. This force can only travel at the speed of light.

      That’s actually important when you get out to astronomical scales. Say you have two stars, Yavin and Hoth, separated by a light year, and pulling on each other by gravity; and say Yavin is moving to the side. Hoth will be pulled towards wherever Yavin was a year ago, not where it is “now”, because it takes a year for the force of gravity to propagate that far. Neat, eh?

      I suspect the term “information” comes from when you’re talking about causality. Under relativity, if you can send information faster than light you can wind up getting the cause and the effect in the wrong order. (Or relativity breaks down, depending on your point of view. ;) How do you send information? The only way is by sending particles or forces (electrons, gravity, etc). I have a feeling the term is being used somewhat more generally than that, though I’m not sure how. Blaine?

      You’re absolutely right about the extrapolation question in the big bang, and there are a number of scientists working on other explanations. There’s a lot of evidence that the universe is expanding, not just from red shift, and they’ve come up with some very nice simulations where they start off with a “primordial soup” and expand everything, and get structures and distributions a lot like what we see today, which suggests that they got the right models in their simulations. That’s not guaranteed, though, and there are still some very significant oddities that are still being looked into — and respected researchers are still looking into alternative explanations, too! But like I said, the big bang describes what we see very, very well, so just about all researchers say “that’s what happened” until we get some very strong evidence to the contrary. (As the Skeptical Inquirer’s motto says, extraordinary claims require extraordinary evidence. That applies to science as much as to pseudoscience.)

      • I suspect the term “information” comes from when you’re talking about causality. Under relativity, if you can send information faster than light you can wind up getting the cause and the effect in the wrong order. (Or relativity breaks down, depending on your point of view. ;) How do you send information? The only way is by sending particles or forces (electrons, gravity, etc). I have a feeling the term is being used somewhat more generally than that, though I’m not sure how. Blaine?

        Yes, generally speaking, “information” is used to refer to that which causality would apply to.

      • Ok, erf, your post bothered me on a couple of levels. First off Yavin is a planet, not a star. Hoth was referenced as a system, so it was a star. :-)

        Second, your contention that gravity moves a the speed of light bugged me. I did not agree with your statement. While wikipedia appears to agree with you, this paper does not.

        • Shoot, you’re right. I was thinking of the phrase “Yavin IV”, forgetting that the base was on Yavin’s moon. Sorry about that. Consider this a fictional alternate universe where Yavin’s a star. ;)

          (Can you think of another star named in SW? Lots of worlds either have their own names or are moons (or both), but off hand I can’t think of another named star aside from Hoth. And even there I’m wondering if “the Hoth system” is a reference to “the system in which the planet Hoth is found” — like some might call this “the Earth system” since that’s the most important part of the system. Thoughts?)

          As for gravity, AFAIK the idea that it propagates at the speed of light is “generally” accepted (although naturally there are people looking into whether that’s wrong — as there should be). This paper, for example, refutes the one you link to, and there’s probably been further exchange since then.

          In any case I can’t see how gravity could propagate faster than light speed without messing up causality. Van Flandern discusses this in that paper, but I’m really not satisfied with his explanation. (I’m also not a GR physicist (I’m in subatomic), so take that statement with a grain of salt.)

    • That’s a whole heck of a lot of experiments to overturn. It’s definitely worth watching, but it could well be that the weak nuclear interaction of the muon has greater impact on the orbit than that of the electron. It really makes me hope somebody does this again with taus orbiting protons and see how that comes out.

  9. Thanks! I look forward to more.

    I did have a question about the statement, “Every massive particle that exists now has always existed and always will exist.”

    While only theoretical and not yet witnessed, proton decay is a possibility. Also, I know anti-protons have been made in the lab (and then rapidly destroyed). Wouldn’t that imply that protons might also be created with enough energy?

    It might be better to step back from the strong wording in that particular statement.

    • Please note that that particular statement is made in the context of a hypothetical world of absolutes. That model will be tested, broken, and replaced in fairly short order.

  10. On molecules and orbits: Planets move smoothly and slowly through the heavens but not think about electrons. There is a heck of a lot of time in 1 second. In fact light can move back and forth over one Angstrom (~radius of an atom) about 3×10^8/10^-10 = 3×10^18 times in one second! Ten to the 18th times! That gives electrons interacting with each other and the nucleus many, many, many chances to jiggle all over the place. We know that for 3 bodies of unequal mass that the orbits can be unstable so that for many electron atoms one would expect a quasi chaotic behavior that spans the space around an atom. The quantum ‘eigenfunctions’ of the Hamiltonian of the atom are only average behavior of the system as a whole but that average is very, very good due to the 10^18 interactions. Push on an atom and it has lots of time to react and adjust to that disturbance.

  11. Bureau42, you need to update this web page as new lessons are posted.

    You do not show the second lesson.
    One must navigate through pages to locate it.

    • Sorry about the confusion. This page was only ever intended as the home for lesson one. I submitted it to Slashdot on a whim, so a lot of people are finding them for the first time and may have bookmarked it like you did. Existing readers would probably know that we would be posting new lessons every Monday, and look for them on the home page. (We’ve been sticking them as the first article on Monday or Tuesday.)

      I’ll edit this page shortly, and try to keep up with the others. Your best bet for using a single bookmark to find them quickly is probably the Bureau 42 Teaches page, which will have this and others. That one is being updated more regularly, and will be updated again Thursday morning to reflect the latest Math Teaching Tidbit (about 16 different mathematical sets.)

  12. I find this statement a bit confusing:
    The basic building blocks of matter, called elementary particles, must all
    have zero volume. What, then, prevents them from piling in so closely
    together that the matter they form does not have zero volume?

    If particles have zero volume, then no matter how closely they pile in together, they should still have zero volume, right? Assuming that 0+0=0
    Or should that say “What, then, prevents them from piling in so closely
    together that the matter they form has zero volume?”

    • Yes, that’s the intent I was getting at, but I see that the grammar could have been better. It is definitely meant to be the “0+0 is more than 0? Why?” thought process.

  13. Quantum Mechanics on Basic Cable

    The Science Channel is running a well done series on the great questions narrated by Morgan Freeman called “Through the Worm Hole”. This week’s episode included the best colloquial explanation of how the Higgs Boson generates mass that I have seen.

    President Obama and an obscure physicist enter a large room full popparotz. Their intention is to simply walk through the room to a door in the opposite wall. As they try to move the popparotz glom onto the President and ignore the physicist. The president’s progress is much impeded while the physicist waltzes through. The attraction of the popparotz for the president is the Higgs field, the individual members are Higgs Bosons, and their retarding effect is inertial (mass).

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