# 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: 4,736 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 36,754 Hi, In Sidney Coleman's Lectures he talked about space translations such that ... Aug29-13 09:03 AM arkajad 1 507 Hi everyone, I'm currently working my way through Dirac's Quantum Mechanics, and I found this proof really... Aug29-13 04:55 AM Oxfordstudent 5 662 Hello! I would like to find a book which covers the historical development of Quantum Mechanics from which I can learn... Aug28-13 04:28 PM Jano L. 2 695 In &5.6 writes: "An (A,A) field (A is spin) contains terms with only integer spins 2A,2A-1,...,0, and corresponds to... Aug28-13 11:55 AM Bill_K 8 1,047 Hi All, Following on from the last dumb question I asked... Suppose you calculate the tree-level approximation... Aug28-13 07:21 AM muppet 2 500 Hi all, It was recently pointed out to me that the finite electron mass puts a lower bound on the Mandelstam... Aug28-13 05:44 AM muppet 4 549 if there are two entangled particles one of them is flying 80% the speed of light , one of them is on earth for... Aug28-13 04:51 AM lyncsta 1 479 Hi PF Somebody gave me this link could you help me to understand why (9) has to be inserted in (7) when the... Aug28-13 04:43 AM naima 2 575 Can we have a local hidden variable theory explanation for Bells theorem? The outcomes of the mesurement (measuring... Aug28-13 03:33 AM haael 7 889 One of the most important results of functional analysis is that for every bounded linear functional f: H → ℂ on a... Aug27-13 09:41 PM strangerep 9 1,055 I had trouble understanding this and had brought it up before but I thought I'd start a new thread on it, in case... Aug27-13 03:31 PM audioloop 8 1,135 Hello! I'm finally starting to get a grip around quantum field theory. The last hang up is the following: I've been... Aug27-13 01:09 PM The_Duck 2 757 Standard Pauli spin matrices are: Sx: $$\left(\begin{array}{cc}0&1/2\\1/2&0\end{array}\right)$$ Sz:... Aug27-13 11:45 AM kith 6 780 I know what the Mossbauer effect is. I know the crystal as a whole accepts the recoil not just the atom emitting the... Aug27-13 07:01 AM Bill_K 1 573 I have been going through my Physics text book to brush up on my Quantum Mechanics before starting my next QM course... Aug27-13 04:11 AM Daniel1992 5 605 After searching this forum for what exactly spin is my inference is that it is a misnomer for an electrons "intrinsic... Aug26-13 06:20 PM San K 28 1,678 Is the non-relativistic Lagrangian: \mathcal L=\frac{1}{2}m \dot{x}^2 invariant under boosts x'=x+vt? It... Aug26-13 12:12 PM Bill_K 5 717 Hello, I'm having trouble calculating this commutator, at the moment I've got: \left=\left=i\left=i\int d^{3}x... Aug26-13 04:59 AM guillefix 5 795 How do I write a full Schrodinger equation, pre-approximation, for a mixture? Let's say 75% H2 and 25% He by number of... Aug26-13 04:17 AM kith 37 2,482 Hi, I am going to sound ridiculous, but I was watching an online lecture on QM and the professor mentioned spins can... Aug25-13 11:01 PM strangerep 1 550 In lecture 2 of the Entnglement lecture series at theoreticalminimum.com, Susskind is explaining a classical... Aug25-13 08:40 PM meBigGuy 5 667 Dear Everyone, I have a problem to be solved now. how to calculate the symplectic group SP(3,R) non-compact induced... Aug25-13 07:16 PM dongsh2 4 507 Dear Sir, I am currently doing an advanced course in Quantum Mechanics. This current doubt of mine, I am unable to... Aug25-13 06:58 PM WannabeNewton 5 984 On page 403, diagram 12.1 (b) of Peskin and Schroeder, does anyone know why the coupling constant at first increases... Aug25-13 06:44 PM Vic Sandler 1 408 Can someone explain how Dirac was able to deduce that anti-matter exists? How did this follow naturally from Dirac's... Aug25-13 02:04 PM tom.stoer 3 619 In the second edition of Mandl and Shaw QFT, on page 361, it's fairly obvious that there is a sign discrepancy between... Aug25-13 12:43 PM Vic Sandler 24 1,700 Could anyone please push to the right direction... Bohr's model of Atom. Energy quantized. Angular momentum. - I... Aug25-13 12:33 PM epsaliba 1 448 Is this a Deterministic Universe ( 1 2 3 ... Last) Does the seemingly random nature of QM mean that the Universe is very non deterministic and does this mean that our... Aug25-13 11:42 AM Tanelorn 65 3,309 How are the Hamiltonian and Lagrangian different as far as preserving symmetries of a theory? Peskin and Schroeder... Aug25-13 11:16 AM jfy4 1 371 Some time ago I asked about contact forces and was directed to read about the Pauli exclusion principle and the... Aug25-13 07:35 AM eightsquare 6 718 It is known that a charged particle moving with some acceleration emits electromagnetic waves. For example, this may... Aug24-13 10:28 PM Ruslan_Sharipov 3 845 Hello all! I'm trying to wrap my head around this quantum entanglement thingy. As far as I have understood, if you... Aug24-13 01:50 PM Bill_K 1 532 The de broglie bohm theory posits that the photon goes through one of the slits and the waves through both. (In a... Aug24-13 01:49 PM San K 14 1,309 If mass is quantised and energy is mass why isn't energy quantised. It seems that it's possible to have arbitrarily... Aug24-13 02:17 AM physorguser 4 906 Sorry for reopening a closed thread. But I have exactly the same doubt as this guy:... Aug23-13 03:39 PM guillefix 2 599 I'm interested in interpretations and comments regarding this Wikipedia snippet: ... Aug23-13 03:14 PM DrClaude 6 693 In the second edition of Mandl & Shaw, QFT, on page 334, eqn (15.28) says: G^{\alpha\beta}_r(k^2) =... Aug23-13 11:54 AM Vic Sandler 0 328 As I understand it, EPR proposed their entanglement thought experiment as a means of demonstrating that Quantum... Aug23-13 11:39 AM RUTA 165 11,966 the two energy level atom, whose hamiltonian takes the form \hat{H_A}=E_g|g\rangle\langle g|+E_e|e\rangle\langle e|,... Aug22-13 06:25 PM bobydbcn 2 533 Is there any thing that could, or any way to increase the atomic decay rate of already unstable elements, such as the... Aug22-13 10:32 AM jfizzix 2 478