Slashdot Mirror
Quantum Physics For Everybody
fiziko writes in with a self-described "blatant self-promotion" of a worthwhile service for those wishing to go beyond Khan Academy physics: namely Bureau 42's Summer School. "As those who subscribe to the 'Sci-Fi News' slashbox may know, Bureau 42 has launched its first Summer School. This year we're doing a nine-part series (every Monday in July and August) taking readers from high school physics to graduate level physics, with no particular mathematical background required. Follow the link for part 1."
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.
Physics that uses no more math than this is not graduate-level physics.
SIGSEGV caught, terminating
wait... not that kind of sig.
Here.
What they don't tell you is the course is a superposition of a nine-part series, and that you can't know what course you are going to get until you actually open the pdf file, which is a pretty dicey proposition these days.
Mathematics is the primary language by which physicists describe the world around us. Discussing post-16th century physics in any other terms is like discussing poetry purely by means of interpretive dance.
discussing poetry purely by means of interpretive dance.
I don't know how you found out about their next lecture series, but I think it would be best if you kept that information to yourself until they get closer to releasing it.
Let me just say, though, that it's almost impossible to truly understand French Medieval poetry until you've seen it performed by a dude in a black unitard.
"Revenge is a dish best served cold - and it's very cold in the vacuum of space. Around 2.725 Kelvin; which is -270 deg Celcius. That is minus 27 tens, and that's terrible....ly cold."
"KAAAAAAAAAAAAAAAAHN!"
Now that's a school I could go for...
I read the first lesson, and while it's interesting, so far I'm not impressed.
It presents some of the problems with classical physics, but it seems to focus on the wrong problems. The first problem it mentions is that information can't travel faster than the speed of light-- but to address that problem you need more than just introductory quantum mechanics, you need relativistic quantum mechanics, and I just don't think you can get to Dirac's equation in a nine part series without math. Then they ask a question about nuclear physics ("what holds the nucleus together?"), for which, to even understand the question correctly, you need some information that the reader doesn't have yet (for example, what do they mean when they say that the only macroscopic force is electromagnetic? In fact, all the forces you do experience in everyday life actually are electromagnetic in nature... but you need quantum mechanics to really understand that! It sure isn't obvious that the force that keeps you from falling through the ground to the center of the Earth is electromagnetic). And this really isn't fundamental to quantum mechanics, either. Next, the nucleus mass question is, once again, a question of relativity and not quantum mechanics (although at least one that can be answered without resorting to the Dirac equation!). And the final question seems to require addressing the equation of state in ultradense matter at the beginning of the universe! Good luck with explaining that with grade school math.
http://www.geoffreylandis.com
This. To grasp even basic quantum mechanics you need to know about linear algebra (to understand the bra/ket notation and why a*b doesn't equal b*a), improper integrals and complex functions (to understand the wave function) and preferably partial differential equations too (to derive the solutions of some simple cases). And that's just the beginning of it.
I really can't see an accurate description of quantum mechanics without quite heavy use of mathematics. This web course might very well be a good introduction to the subject, but if you really want to understand where quantum mechanics comes from, you'll need a bigger mathematical toolbox.
By abstracting all the mathmatical conjecture. But then, you're left with "A brief history of the universe", and I suppose, tack an exam (of course, abstracting from the math), and you now have a "graduate-level" course.
Hi, I Boris. Hear fix bear, yes?
As a CS student I have not studied much physics; but I'm a very curious guy so I could not resist to follow the link. Their requirements are: average level intelligence, basic maths and a PDF reader. Sounds like perfect for me... or too perfect? W. Blaine Dowler took his time to write in LaTeX, which automatically made me think it can be trusted - don't ask me why. But, on second thoughts, this doesn't sound right.
At back at school we were taught that physics has laws and mathematical models, which are an (simplified) generalisation of the empirical data. If there's no mathematical description, what am I going to learn? 3 years ago I heard about "Schroedinger's equation". I couldn't resist my curiosity and searched it in Wikipedia. Nice greek letters and strange symbols. The teacher told me it's result described an area where it was more probable to find an electron. Wikipedia said it means much more. So now I'm sceptical about this mathless physics: they are going to make a lot of unexplained statements, and in the end I wont get any practical results out of it, and anything they write will be so over simplified that it would have lost all its meaning, just like my teacher. I won't "know" quantum physics.
In soviet russia the government regulates the companies.
It's more like discussing modern dance by performing it as a sequence of ballet moves.
Or deconstructing poetry.
Or using your words instead of your numbers.
In the end, mathematics is a means of manipulating facts to reveal other facts in a deterministic manner (even if they're facts about non-deterministic things). If you can't subsequently describe both sets of facts in terms a non-mathematician can understand, you haven't reached a result that non-mathematicians will know about, much less be able to form the idea that they should ask what it means.
Physics, being the means of describing the natural world, can be conducted in non-mathematical terms, since the math is just a symbolic model of the physical features, which exist regardless of the shorthand you used to reason about it.
Math will help you turn one symbolic model into another, but unless you understand what the subsequent model means when turned back from symbols into physical concepts, you haven't done any physics.
You tell 'em, you "villain", you!
To be, or not to be: isn't that quite logical, Slashdot Beta?
This is just a reprinting of Fred Wolf's 15 chapter "Taking the Quantum Leap" as 9 chapters?
That math may be why Quantum Physics waits until the graduate level. I've seen more people lost in the formulas than those who understood the concept without the math.
I'm going to be charitable and assume that the rest of the post is provided as a counterexample to this statement, and therefore not call you a fucktard for what follows.
Clearly, "Relativity" means "E = mc^2".
No, it does not. Perhaps you meant the longer "E = mc^2/sqrt(1-v^2/c^2)". Even that, however is wrong. There are two core principles to relativity:
- light always travels at c in a vacuum, independent of reference frame
- the laws of physics are the same in every non-accelerated reference frame
Everything else follows from this; even the specific form of the Lorentz transformation can be determined (using these assumptions) with some simple math and thought experiments.
Very few people can explain the E, m, c, & what they represent. I'd like to hear someone say "Matter has energy proportional to its mass.", which is still not the most import aspect of Relativity.
This was true even before relativity; "0.5mv^2", remember?
For example, the speed limit c on particles insures that kinetic energy (K = 1/2*mv^2) cannot grow forever. Otherwise, energy could be created.
I rescind my opening statement. You, sir, are a fucktard. That isn't even CLOSE to what's going on. "Kinetic energy" (by the modern definition, total energy - rest mass) can and does grow without bound. Particles are regularly created in labs with "kinetic energy" vastly in excess of their rest mass. *Velocity* on the other hand, is strictly limited.
BTW, particles CAN be created via this process - hard X-rays (somewhat above 1 MeV energy) can photoproduce electron-positron pairs when interacting with matter.
These ideas help one to understand the Physics and the math that describes it.
Maybe for some people. You, on the other hand, fail it.
With your math background I think that the book 'Quantum Physics of Atoms, Molecules, Solids, Nuclei, and Particles' by R. Eisberg and R. Resnick would be a good read. That's the book I am reading for a one year class on modern physics.
That math may be why Quantum Physics waits until the graduate level.
Pretty sure quantum mechanics gets taught to undergrads (for some definition of rigorous). And even at that "elementary" level, some amount of math is invaluable to intuit quantum weirdness. For example, I'm not sure what the conceptual/non-mathematical understanding of the (quantum mechanical) car bouncing off the edge of the (quantum mechanical) very high vertical cliff would look like; however, the only vaguely mathematical explanation is quite simple and concise.
Yeah, introductory quantum mechanics is introduced typically in second year, and then more detailed versions including Dirac notation show up in third and fourth year. The graduate level is where relativistic implications are usually taken into account, unless you take senior undergraduate particle physics.
- W. Blaine Dowler
http://www.bureau42.com
...including Dirac notation...
In the interest of gender equality, I tried to introduce Jok-Strap notation. It didn't catch on.
Agreed. As Pauli might say, physics without math is "not even wrong."
I will add to this one of the greatest physicists around, Albert Einstein, did not know the necessary maths when he wrote his first theory. The maths was done for him, though he did later learn to do mathematics.
Science as we know it is not about the maths, but being able to produce a solid theory that stands up under scrutiny. Using scientific process helps add weight and often mathematics can provide a calculable way of showing numerical relationships, but if the reasoning for the theory is sound then these are just bonuses, IMHO.
Jumpstart the tartan drive.
Even worse than what happens for the insiders is what is left for the outsiders: demagogues, televangelists and industry funded anti-science groups convince those outsiders that the insiders are elitist and despise the outsiders' lack of knowledge... also poisoning the well of understanding while gaining their trust "against the elite science crowd".
Making advanced knowledge as accessible (without reductionism) as possible is the best hope for our continued development as a society and species.
Make sure everyone's vote counts: Verified Voting
He only uses the math as the final step, to describe what he sees in his head, not because he enjoys it.
Exactly - in order to describe physics you have to use maths. It is certainly possible to teach the basic concepts but if you think you are learning "graduate level" physics you clearly have no idea what graduate level physics is because that requires maths in order to communicate a full understanding even though the understanding in your head will be in "pictures".
For example I can simply tell you that in nature every symmetry produces a conserved quantity. You can think about it for a while and perhaps convince yourself that this is true. However without understanding Noether's theorem and basic Lagrangian mechanics your understanding will be far from complete and, worse, you will have no way to be able to calculate what the conserved quantity is given a particular symmetry or vice verse....and this isn't even graduate level, its second year undergrad!
Love is the behavior which is the result of chemical reaction in the brain and the body (neurotransmitter, hormone, neuron state etc...). Love *IS* based on chemistry , and therefore fully based on electromagnetic force, QM. All our emotion are based on chemistry. A complicated system, surely, one for which we have only superficial model definitively, but in absence of evidence to the contrary, those are definitively system where only biochemistry is at play.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
Logic at his purest form is not dependent on *ANY* material. Philosophy involve more than logic is dependent on logic, the same way physic involve more than math but is dependent on math. So philosophy is applied logic to idea and existence etc... Logic is not a subset of philosophy, philosophy is USING logic. Otherwise you could declare math a subset of physic. So at the core of EVERYTHING, logic, is there present and the most purest of all material.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
The paper is simply packed with logical fallacies. Yes, many of these are commonly accepted in the physics community, and are indeed the cause of the current pithy state of physics research, that continues to leap from one absurd conclusion to the next, discarding logic in the process. But is it really a good idea to pollute the minds of the next generation with them? The paper starts with a misconception right from the start:
> Nothing, not even information, can travel faster than the speed of light.
Here is a fine example of the mind projection fallacy: failure to distinguish between reality and what you think about reality. Information is not a physical object. A physical signal varying in an informative (to you) way is indeed limited by the speed of light, but the transfer of information is not necessarily limited to a direct transfer of measurements through a physical signal. An obvious example are the current research into "entangled" particles, where you can create two particles with correlated properties and by measuring the parameters of one know the parameters of the other. Because of the mind projection fallacy, physicists still think of this as "spooky action at a distance", even though no "action" has occured except in the experimenter's mind. No physical signal was sent from one particle to the other, only information was "sent" from the experimenter's mental model of one particle to the mental model of the other. Such virtual "transfers" are limited only by the size of the containing brain. Understand this, and you'll see why we must always make the distinction between what we think and what is. Unfortunately, the very formulation of quantum theory forbids such questions. In section 2.4 we see a continuation of this insanity:
> If we have an electron orbiting a nucleus, then the electron "knows" of an opposing electrical charge of the nucleus.
Quantum theory models all interactions as particle exchanges and thus has mostly lost the concept of a field of force. We could, for instance ask the very same question about the earth orbiting the sun and receive an answer that the gravitational field deforms the space around the sun and the earth, and that the interaction of their curvatures produces the gravitational force. Likewise, we could imagine charge curving some "electromagnetic space" and causing protons and electrons to interact in the same manner. (Interestingly, the old ether theories were "disproved" because we could not find effects of motion through it, even though the gravitational space does not appear to manifest any absolute velocity either)
> In other words, information about that charge has been received. In order to manage that, energy must be transmitted away from one or the other. How does the energy get replenished?
How does the "energy" get replenished when the earth moves around the sun? The answer, of course, is that there is no energy transmission, or information transmission. Neither the electron nor the earth is an intelligent entity capable of processing information in the same way we do. Physical objects merely interact with local space, creating gravitational deformation, and space then arranges those deformations into a minimal energy configuration, which, in the case of the earth, just happens to be an orbit around the sun. The same happens in the nucleus, except that the minimum energy levels are limited by quantum effects (why they are limited is a whole different discussion, and one that quantum mechanics simply postulates without any explanation whatsoever).
> In a world of absolutes, where particles are immutable and indivisible, the particles also become invincible.
Where the heck did he get that? Particles and antiparticles can annihilate into electromagnetic radiation, and radiation can create particle-antiparticle pairs. No, we don't know why that is so. Quantum mechanics has a mathematical model that can calculate the parameters of the interaction, but offers no explanation of how it actually happens (nor c
em in the body stopped being novel years ago.
Now it is just annoying.
That is by far the funniest joke that no-one will get that I have read all day.
I would absolutely recommend David J. Griffiths' "Introduction to Quantum Mechanics". It's blue and has a cat on the cover (and a dead cat on the back), hence it is sometimes known to physicists as "the cat book". Multivariable calculus, linear algebra (with a small emphasis on abstract algebra if possible), and diffeq (partial, not just ordinary), are exactly the math that you need to grok everything in Griffiths. It is one of a few standard undergrad (usually sophomore or junior level) texts, and, in my opinion, the best written among them.
Another poster recommended a modern physics text, but I would disagree that that is your best choice. Modern physics texts tend to be great at going "wooee! look at how weird the universe is!" and touching briefly on a whole bunch of the seminal experiments and theories, but without really going into much of anything in any sort of depth.
SIGSEGV caught, terminating
wait... not that kind of sig.