Quantum Theory

Both QM and relativity (which uses mainly diffential geometry and tensors) require a thorough backround in CM and Electromagnetism (including classical electrodynamics). So Quantum Mechanics (non-relativistic) uses linear Algebra (especially complex numbers, matrix algebra and linear transformations), functional Analysis (Hilbert spaces), advanced calculus & diffential equations (ordinary diffential equations & partial differential equations). QM also uses Harmonic analysis using Fourier series & transforms. What else? Can someone give a little more information? Edit: So basically modern QM is a combination of Werner Heisenberg's matrix mechanics with…

This started off in another thread, but was inappropriate there, so I will post it here. The question began from considering that the inertial mass of an object is due to some electromagnetic interaction of the object with the quantum vacuum. Haish, Rueda, Puthoff ZPF Theory So the question is, what is a virtual photon? The question originated from a paper with this in the abstract: Two Scientists Alfonso Rueda and Bernard Haisch have worked on a paper titled; Gravity and The Quantum Vacuum Inertia Hypothesis, where they suggest that virtual photons, there as a result of Heisenberg’s, uncertainty principle, are turned into real particles by an accelerati…

Why do us as humans try to put everything on a lline? For example why when we think of our universe and out demension are we just one line of many? And Why do we try to make everything into a line like time and what is on the other side of that line here is an example- ___________________________we are here on this line__________________ What is over here I assume that it is not just a void there has to be something and what is it? And a Ray is a line remeber 9th grade Geometry

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according to what I`ve heard, matter as we know it (Baryonic) is only about 4% of the Universe, another 25 to 26% is made of Dark Matter. the rest is made up of Dark Energy (70%ish) it was also said that very little is know of Dark matter, and even less of Dark Energy. the radio program didn`t go into great detail of anything (it was kinda dumbed down). so, does anyone have any more info about this?

More than that, why the flaring would we measure time with imaginary numbers?!

the force F = c4/(8piG) is the main constant in Gen Rel. The constant in the Einstein equation is actually not Newton's G, but rather F. In Quantum Gravity one often uses units in which |F| = 1 (this can come about by stipulating that |8piG|=1, since normally one already has adjusted the units so |c|=1) in keeping with the natural units idea we can also set Boltzmann k (the temperature energy ratio) and the electron charge equal one. the moment one sets |F|= |c|=|hbar|=|k|=|e|=1 one has a fairly universal set of units and it is interesting to see what some familiar quantities come out to be. As a convenience in trying out the units and getting some practice w…

Right imagine a Piece of Radioactive material. We have been steadily decaying for many years. Finally there is just 1 stable isotope ready to go under alpha decay. The atom has a half life of one day. But wait we cant have 1/2 a decayed atom at the end of the day, so is it totally a random chance whether the atom will decay in one day? (yes i know QM says its random anyway). Now im pretty sure the GCSE course is about to make us draw graphs that curve off and it will probably tell us it never hits the x axis, but if the answer is yes to the above question, then it must do. Or will we be tought its just slows and does (randomly) touch the x axis sometime in the future?

Since neutrinos are so small but do actually collide with our smallest particles at times, to be able to observe them in the future we are going to need some fascinating engineering. Our limits today are we can only observe in collisions the effects of the smaller particles we need as tools. We observed the efects of electrons in the past and then isolated them and now we photograph using controlled beams of them them. We see a neutrino because it collides with something we know which will explode in an observable way. The best way to actually abserve them in my opinion is to generate one of the smallest parts created out of the explosion and try to aim them in a con…

this came out today http://arxiv.org/abs/gr-qc/0503041 A black hole mass threshold from non-singular quantum gravitational collapse Martin Bojowald, Rituparno Goswami, Roy Maartens, Parampreet Singh 4 pages, 3 figures "Quantum gravity is expected to remove the classical singularity that arises as the end-state of gravitational collapse. To investigate this, we work with a simple toy model of a collapsing homogeneous scalar field. We show that non-perturbative semi-classical effects of Loop Quantum Gravity cause a bounce and remove the classical black hole singularity. Furthermore, we find a critical threshold scale, below which no horizon forms -- quantum grav…

I have a question. Is a black hole really hot, or really cold? Thank you

http://www.math.columbia.edu/~woit/blog/archives/000165.html a fine conversation in progress at Not Even Wrong choice tidbit: Chris W remarked "In a way, all this reminds me of the contrast between Lorentz's and Einstein's explanations of the null result of the Michelson-Morley experiment." Thomas Larsson replied "We live in a region of the Landscape where the aether wind is very small, because a large aether wind is not compatible with human life." Here is Chris post, for context: "In a way, all this reminds me of the contrast between Lorentz's and Einstein's explanations of the null result of the Michelson-Morley experiment. The fact to b…

Seems like a simple question, cos we can see it? I'm not sure what sort of answers I'm gonna get, "cos it does, stupid", "cos einstein says so" or a link to another thread. My problem is in accepting light as a stream of particles (photons) that "travel" from one place to another. My preception is that as an energy change takes place, like fusion in the sun, and electrons get excited, it produces an EM field as oppose to creating a photon travelling away from the source. This EM field effects other surrounding matter, a bit like an iron filing is affected by a magnet. An example would be a cars headlights. From the side we can't see the "beam" of light (unl…

Does light of equal frequency interfere as originally thought or is it the individual photons primarily "interfering with themselves"? Or do we know?

Can comeone explain the difference between spin 1/2, spin 1 and spin 2 in such a way that the numbers make sense. I realize they mean quantum spin and relate to classic spin by analogy only but in what sense is spin 2 "twice" spin 1, or spin 1 "twice" spin 1/2. I realize also that spin 1 and 2 are in a different "family" than spin 1/2.

If you start out with Schrodinger's equation, and then derive the total energy of a free particle, you get [math] \frac{mv^2}{2} [/math]. But suppose that instead of using the ordinary Laplacian, you use this instead: [math] \nabla^2 = \frac{\partial^2}{\partial x^2} + \frac{\partial^2}{\partial y^2} +\frac{\partial^2}{\partial z^2} - \frac{1}{c^2} \frac{\partial^2}{\partial t^2} [/math] Then in this case you get: [math] E^2 = (pc)^2 + (m_0 c^2)^2 = (hf+ m_0c^2)^2 [/math] As the total energy of a free particle, unless I made a mathematical error somewhere. So if this is right then the total energy of a free particle is given by: [math] E = hf + m_0 …

I've checked out superstringtheory.org and some other places, but I haven't found something that gives a very basic overview of what strings are. Like, how were they developed? What problems do they solve? How do they behave? The string theory website was very in deapth, but without a proper background I just couldn't make sense of what they were saying. I realize that describing this stuff can be tough and time consuming, so thanks in advance.

Would it be possible to construct a box where all 6 sides on the inside were mirrors, so that if you opeded it in a bright room, closed it, and then opened it in a dark room, light would flood out?

In this thought experiment a live cat was placed in a box with some device which could render it live or dead after some specified time. Schroedinger noted that the device's outcomes could be represented mathematically (his wave equation). Because the outcomes of the equation are "indeterminate" (unknowable until known) he suggested that the cat's status was indeterminate and it was in a "superposition of states" that is, neither live or dead. Do you think that (a) Schroedinger was trying to point out the absurdity of applying QM to the world in which cats live or (b) you know the physical process whereby a live cat can be rendered neither live or dead…

Is it possible to store entangled photons for a period of time, and then use them later?

my chemistry teacher said it is impossible to calculate the entire energy of a particle but i disagree. it may sound stupid but i'm still in highschool.

If a photon has mass then it can't possibly reach the speed of light, but if a photon is massless then it can't be affected by gravitational fields, and surely in reality, it is affected. The way I see it, if a photon has 0 mass, then not even the mightiest of black holes can affect it's course.. One argument could be that the photon just transports mass from place to place, while not actually having the effects on itself. But, saying that theres no effect on the photon by the mass it carries, is like saying that the photon is not a player in the gravity game. Ofcourse this is a paradox.. And I'm probably missing something. Anyone?

hey guys, im having trouble with the heisenberg uncertainty principle equation! can any1 help me with this question? Given that the mass of an electron is 9x10^-31kg, calculate the lowest uncertainty in position and velocity for the electron. (i think this is meant to be a really easy Q but i still dont get it *sigh)

Suppose that I wanted to model the universe as a collection of an integral number of bodies, and then intelligently discuss changes in the state of the universe. Suppose I choose to represent the state of the universe by the symbol [math] \Psi [/math]. Now I want to focus on a single change of the state of the universe, which I will represent using: [math] \Delta \Psi [/math] Here is my question. Why would it be wrong to say that the state of the universe has changed if and only if the center of inertia of at least one object moved relative to the center of inertia of another? Regards

Hi Guys, Could any of you recomend any books for someone who doesn't know much about quantum mechanics but wants to improve his knowledge with somthing not too complicated?