Hi everybody! I'm studying this paper "Unambiguous discrimination among quantum operations" http://pra.aps.org/abstract/PRA/v73/i4/e042301 and they state that
Ok, it's well known, but then I took a review of the notes to my course of quantum information and i found this not proven proposition...
Forgot to say:
wave vector \textbf{k} is in radiant/second
energies are in radiant/second
position vector \textbf{r} in cseconds with c speed of light.
Unable to "decrypt" emission/absorption matrix element
Hi to everyone! I'm reading an example of atom radiation interaction (more precisely, an atom emits a photon which photoionizes another atom) on an old book (60s) and I'm facing a matrix element which I never saw. I mean, I'm not able to...
First of all thanks for the detailed explanation. Second, I think I get the point now: reasoning about the photon bosonic nature and the interference of wave function based on their indistinguishableness (so enhanced probability). Like for the explanation of the Hanbury-Brown and Twiss experiment.
Thx Cthugha for the explanation but still I can't get your point about the reversed picture. Using the Fermi Golden Rule I can calculate the emission rate and I can SEE that the emitted photon has the same energy of the difference between the two atomic levels, but I can't see from where comes...
Thx for the link! I've just downloaded the lecture. Now I'm reading also "the quantum theory of light" by R. Loudon. But just as final question, what would you answer to the simple question "why a photon coming from stimulated emission must have the same vector momentum of the initial photon?"
Thx Cthugha! I've already taken read chapter 15 of Mandel and Wolf but not specific answer. I will try to take a look on your suggested Cummings papers. Thx a lot.
All semiclassical treatments (without involving Einstein coefficients but perturbation theory) I found, are about one photon...
Thx. But I need something more specific. Like 99 out of 100 books, even your link from wikipedia states
I'm looking for a full quantum treatment (or at least semiclassical/time dependent perturbation theory/harmonic perturbation, Fermi GD and so on...).
I've already searched a...
Hi everyone! I will very thankful to whom can suggest me some texts or webpages where I can find a demonstrated explanation of why photons emitted by stimulated
atoms travels in same direction of the photons which interact with the atoms. Every
author says photons are coherent, same phase...
Ok thanks. I get everything, now. I was missing the point about the derivatives.
Can you help me, please, to understand why I get always a symmetric energy-momentum for a theory of scalar fields?
ok, I've understood my error. Thanks! So, finally I get
T^{\mu\nu}=\partial^{\mu}\phi\partial^ {\nu}\phi-\eta^{\mu\nu}(\frac{1}{2}\partial_{\mu}\phi\partial^{\mu}\phi-m^2\phi^2})-\frac{\lambda}{4!}\phi^4
and I'm sure that until this point the tensor is correct. But how can I see that...
Considering the terms between the brackets, the first one is obtained deriving the Lagrangian respect to \partial\phi; the second one, with the minus sign, is obtained raising the index of the first 4-gradient... with + sign the terms in bracket with the 1/2 factor would be the common...
I'm studying the properties of the energy momentum tensor for a scalar field (linked to the electromagnetic field and corresponding energy-momentum tensor) and now I'm facing the statement:
"for a theory involving only scalar fields, the energy-momentum tensor is always symmetric". But I've...