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: 124,334 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 35,536 Hi, there Today, a friend came to me and asked the following questions and they made me confused. If the source is... Jun8-14 09:17 PM Robert_G 5 339 Why is quantum physics needed to explain photosynthesis? In what aspect does the corresponding classical theories... Jun8-14 11:23 AM HeavyMetal 2 265 Hey! I did an quantum mechanical analysis of a Hydrogen Atom in a homogeneous magnetic vector potential (I know... Jun8-14 11:00 AM Vanadium 50 6 305 I'm a bit of a non-classical physics newbie here, so let me check my (rudimentary) understanding of some things first.... Jun8-14 10:10 AM mfb 6 383 Hello and apologies if the title of the question is not very precise. Question: I am reading the document talking... Jun8-14 09:07 AM UltrafastPED 1 141 This is a question about The Computational Capacity of the Universe by Seth Lloyd. It seems to me that arbitrary... Jun7-14 11:57 PM bhobba 3 239 I am referring to an experiment mentioned in Quantum Entanglement lecture:... Jun7-14 10:51 AM RobikShrestha 6 290 this might be a dumb question, but, if spacetime isn't a field and gravity is a property of spacetime. then gravity... Jun7-14 03:35 AM bloby 7 454 Sometimes it happens that hamiltonian has degenerate eigenvalue. This degeneracy can be removed by modifying the... Jun7-14 03:32 AM Jano L. 8 316 If I understand it, Hilbert spaces can be finite (e.g., for spin of a particle), countably infinite (e.g., for a... Jun6-14 02:11 PM samalkhaiat 35 1,132 Two entangled photons from a same-polarization source have their polarization measured at 120 deg difference from each... Jun6-14 09:17 AM DrChinese 1 240 This post is my reply to a blog comment by billschnieder, since I do not think it is wise to start a discussion in the... Jun6-14 06:54 AM georgir 0 270 I have a question: can the mechanism behind Pauli's exclusion principle be considered a fundamental force, like... Jun6-14 06:35 AM tom.stoer 9 415 Hello everyone. I was yesterday asked in an interview to draw a gaussian curve. I drew. And then they asked in what... Jun6-14 06:18 AM suvendu 8 285 Hi. I am very much interested in physics but my locality lacks good college for undergraduate physics but has good... Jun5-14 11:41 PM bhobba 1 412 Hi, everybody: I encountered a problem when I am reading a book. It's about the atom-photon interaction. Let the... Jun5-14 04:18 AM strangerep 1 241 If I define a state ket in the traditional way, Say: |\Psi \rangle =\sum _{ i }^{ }{ a_{ i }|\varphi _{ i... Jun4-14 02:39 PM atyy 5 337 is equal to the amplitude squared in quantum mechanics. Why? Jun4-14 08:01 AM naima 17 759 What is the coherence time for a pair of entangled photons produced in a nonlinear crystal? Is it related to coherence... Jun4-14 05:51 AM Cthugha 4 329 Is the trace of an outer product of a normalized state eq. (psi) equal to 1? Thanks, Chris Maness Jun3-14 09:50 PM dextercioby 4 244 I was watching Richard Feynman's lectures on quantum electrodynamics where he concerned the probability of photon to... Jun3-14 07:33 PM UltrafastPED 1 234 This oft-referenced picture depicts a simulation of virtual particles popping into and out of existence in the empty... Jun3-14 12:07 AM tom.stoer 2 311 It is available for free from this source. If someone can explain what has really been done here in simple English,... Jun2-14 10:57 PM gelatin 2 262 If spherical harmonics are simultaneous eigenfunctions of \hat{L} and \hat{L}_{z}, then that means for a state at... Jun2-14 03:53 PM siddharth5129 2 220 I learnt about the EV cases. But what if V=E? Can we at all conclude V=E due to uncertainty... Jun2-14 02:17 PM suvendu 0 228 Hey, i hear about quantum teleportation on the news today. They said that they successfully teleported information.... Jun2-14 12:43 PM Thinkor 19 749 A friend is a quantum chemist. He is in agreement that climate change is bad (he feels the primary problems with CO2... Jun2-14 06:27 AM D H 1 283 I have some questions regarding the Heisenberg picture of QM. 1. How does one calculate probabilities for measuring... Jun2-14 12:13 AM atyy 1 347 I am going through James Binney's course on Quantum Mechanics. I love all of the little misconceptions he points out... Jun1-14 06:30 PM Matterwave 13 371 Hello look at (3.24). Above it, it states "We make the same switch to polar coordinates (x, φ) in the (x, y) plane,... Jun1-14 06:14 PM epislon58 2 227 Do individual photons have some attributes which relate to EM wave frequency? In other words, is there any difference... Jun1-14 12:28 PM Nugatory 7 368 Index Notation & Dirac Notation ( 1 2 3 ... Last) Quantum Mechanics using Index notation. Is it possible to do it? I really don't get the Dirac Notation, and... Jun1-14 09:00 AM atyy 105 2,587 Is it true that there always exist a unitary matrix that can take a state vector of an arbitrary pure state to another... Jun1-14 03:19 AM tom.stoer 7 522 The eigenstates of a hydrogen atom are stationary states with definite values of energy. Now, as I understand it, the... May31-14 05:33 PM dextercioby 4 280 A new type of energy storage described which uses quantum way to store energy. ''Battenice''. ... May31-14 09:08 AM mfb 1 462 I am able calculate the solution for the TISE relating to the interval to the right of a step potential; however, I am... May31-14 02:52 AM Simon Bridge 27 1,061 Is Timespace a literal real thing? or is it an abstract idea? and what makes physisists so sure that gravity is a... May30-14 07:44 PM bhobba 3 425 I am looking around for some sort of equation regarding optical power dissipation of light (ultraviolet light in... May30-14 12:53 PM Jano L. 1 253 Hello, I need help understanding how to apply the formula for converting a Lagrangian to an equation of motion in... May30-14 09:14 AM sloneranger 8 275 Hi everybody, Is it possible to obtain an expression equivalent to fermi golden rule within the framework of Green... May30-14 08:08 AM Arthas85 0 215