# Quantum Physics

- Mathematical description of the motion and interaction of subatomic particles. Quantum Mechanics & Field Theory
 Meta Thread / Thread Starter Last Post Replies Views Views: 2,687 Announcement: Follow us on social media and spread the word about PF! Jan16-12 Pinned: Quantum Physics Forum Rules Before posting anything, please review the Physics Forums Global Guidelines. If you are seeking help with a... Feb23-13 08:38 AM ZapperZ 1 36,471 Although it is well known that a series of individual photons will build up an interference pattern in a double slit... Apr22-13 05:49 PM DevilsAvocado 9 5,293 Ok so the equation E= hf about the energy of a photon, I'm having a problem understanding energies to do with photons.... Apr22-13 05:04 PM dextercioby 5 678 Lets say we have a potential step with regions 1 with zero potential ##W_p\!=\!0## (this is a free particle) and... Apr22-13 12:16 PM 71GA 15 1,349 1.does antiparticles really travels backwards in time or is it just used to describe feynman diagrams and diracs... Apr22-13 09:56 AM bhobba 14 1,183 I was reading Griffiths's book on quantum mechanics. In chapter 6, he tried to derive the spin-orbit coupling using... Apr22-13 07:14 AM Bill_K 2 532 Is there an intuitive way of understanding these terms? I understand the mathematics that shows why there are 3 states... Apr22-13 01:49 AM DrDu 2 619 Exotic matter have a negative mass and goes in the opposite direction of the force applied to it. These properties... Apr21-13 09:02 PM HomogenousCow 5 598 I know there's a flaw here as superluminal communicaton is impossible. I was considering this scenario: As with... Apr21-13 03:40 PM bcrelling 7 925 From 'Modern Quantum Mechanics, revised edition' by J.J. Sakurai, In page 44 the translation (spacial displacement)... Apr21-13 02:55 PM micromass 2 618 Do you think that: Single particle interference is explainable via entanglement? For example: in the single... Apr20-13 07:21 PM Vanadium 50 5 869 I am really confused about this! So people thought that as wavelength increases for electromagnetic radiation,... Apr20-13 01:11 PM Nugatory 5 635 In the infinite square well, the stationary states solutions form a complete set, and therefore I can write a function... Apr20-13 07:33 AM stevendaryl 5 628 I need help proving the identity ... Apr19-13 11:46 PM arkajad 27 4,352 Hi, I am currently studying quantum field theory with worldwidely used text written by Peskin and Schroeder. On page... Apr19-13 10:41 PM ndcat10 2 541 Hi guys, is there a reason why the energy of the harmonic oscillator is always written as: E_{n} = \hbar \omega... Apr19-13 02:38 PM dextercioby 1 488 why do we have moving detectors in Delayed Choice Quantum Eraser (DCQE) and similar experiments? Why don't we have... Apr19-13 02:00 PM San K 0 378 Hi everyone, I'm stuck on the concept of the rotation operator in QM. From what I understand, one constructs a... Apr19-13 12:58 AM tom.stoer 5 863 Does anyone have a link or a reference to somewhere where these rules are explicitly derived for phi-four theory? Apr18-13 08:46 PM bhobba 4 973 I'm not clear as to how the overall interference pattern (or lack thereof) observed in the quantum eraser experiments... Apr18-13 06:46 PM msumm21 6 728 With reference to the following lecture by Leonard Susskind :... Apr18-13 02:14 PM dextercioby 1 482 If I use hydrogen-like orbitals for other atoms, how are the number of nodes and probability density affected? Apr18-13 12:01 PM cgk 2 519 It is often said that the photon is the long range force carrier like the static force between electrons. Lets say we... Apr18-13 11:48 AM ftr 2 670 Also how can local causality be violated? Apr18-13 09:52 AM DrChinese 1 436 Hi I am teaching myself QFT using peskin and schroeder and have a few problems 1) On page the author goes from \int... Apr18-13 09:49 AM pleasehelpmeno 0 395 Hi Guys For all people interested in Schrodinger's Cat check out Leonard Susskind's explanation - very lucidly... Apr18-13 09:47 AM bhobba 0 845 Dear all, I am working on 8 band k.p model and I am intrested in the way of derivation of explicit analytical... Apr18-13 08:41 AM aziziph 0 426 The principle states: δxδp≥h/4π I understand what it means and ive seen in proven both theoretically and... Apr17-13 08:00 PM fluidistic 4 746 In its standard formulation, the CPT theorem says that any local Lorentz-covariant quantum field theorem will be... Apr17-13 07:22 PM LastOneStanding 2 547 Why did Max Planck refer to his own radiation law... Apr17-13 05:07 PM LayMuon 1 885 In the one moment you accept something in the other you're not sure why? Why probability density in quantum mechanics... Apr17-13 12:14 PM ttakacs 11 1,368 I am very confused by the treatment of Peskin on representations of Lorentz group and spinors. I am confronted with... Apr17-13 10:29 AM silverwhale 13 1,106 I can't seem to find a definitive answer to my questions surrounding this topic, every textbook I read is rather... Apr17-13 09:47 AM fzero 4 625 What is the quantum of an electromagnetic wave? Quantum of light is photon. What is the quantum of a gamma ray or an... Apr17-13 06:53 AM L4xord 4 594 Hi guys having a little trouble with two-qubit state multiplication. Could you tell me how you work out the... Apr17-13 05:32 AM kith 5 642 The Wigner function, W(x,p)\equiv\frac{1}{\pi\hbar}\int_{-\infty}^{\infty} ... Apr17-13 05:01 AM Bill_K 6 771 Hi all! I was reviewing some basic quantum mechanics, and I was trying to 'derive' the equation -i \hbar... Apr16-13 06:38 PM BruceW 8 987 We know electric current travels around 200000 km/s.. Yet electrons are moving way much slower, just acting as a... Apr16-13 04:34 PM ExecNight 4 648 As an atmospheric physics major I am familiar with electromagnetic radiation in the atmosphere and what dictates what... Apr16-13 03:06 PM Naty1 5 858 In the chapter on partial wave analysis in Griffiths's Introduction to Quantum Mechanics, he considers a spherically... Apr15-13 08:33 PM Meir Achuz 4 1,085 Reflection/refraction of light is due to the absorption of photons by electrons in the governing atoms, and is then... Apr15-13 08:29 PM Meir Achuz 4 533