Recent content by Zarqon

For atomic systems the AC Stark shift is usually approximated as ΔωAC = Ω2/4δ, where Ω is the Rabi frequency of the transition (depends on electric field of the laser and the dipole moment of the transition), and δ is the detuning. I don't see any reason why it would be different for molecules...

I find it much easier to understand the processes of absorption and emission by thinking of fields and charged particle distributions. Consider an electron distribution in the ground state of an atom (let's say an S-type wavefunction). To simplify, this has a charge distribution that is...

Well, the gain medium provides the inverted population, ready to give away photons. But the coherence/phase of the photons that are created through stimulated emission is set by the seed photons that first decayed (randomly) and then travalled around the cavity. The act of going around the...

I haven't quite read all of the answers so far, but I'll just try to answer your original question. The increase in coherence length of a laser has nothing to do with the atoms at all. The coherence properties of a laser comes from the mirrors used in the laser cavity (of course some times you...

There's a very recent paper By Stephanie Wehner and others describing the updated vision for the Quantum Internet At the start of the paper they give the following motivation for quantum communication: "As with any radically new technology, it is hard to predict all uses of the future quantum...

As PeterDonis mentioned, there are several features of the quantum cases that do not easily carry over to the classical analogies. One thing about two entangled coins is that separately they behave randomly, but together they're not. For example, if you have many pairs of entangle coins, then...

heh, some current events suggest that we are just that stupid... On a more serious note though, I believe it's not a matter of stupidity, I think it is inevitable that we put our decisions at the hand of an AI. Consider for example any company making business decisions; we know that humans...

I still find the poll a bit too incomplete. Why did you put a division between theory and experiment only for two disciplines? Certainly most areas have this division. Also, several big areas are missing entirely: Atomic physics, Molecular physics, Quantum physics etc. I voted other because of that.

The Peres-Horodecki criterion is necessary and sufficient only for 2x2 and 2x3 systems, see e.g. the arxiv version of their paper: https://arxiv.org/pdf/quant-ph/9605038.pdf

They are both in principle stimulated emission yes, but the seeding photons are different. What you want in a laser is that all photons in the inverted population gets stimulated down into the specific narrow cavity mode that your mirrors define. However if a photon, for example, spontaneously...

Hmm, first wrote some more advanced strategy with different orderings of cuts and choosings, but now I think a simple solution is better: Let one person cut the cake in three pieces, the other two pick first, and the one who cut gets the remaining piece. The only way for the cutter to maximize...

I just came across this paper about entangled histories as well, and thought it better to continue in this thread rather than opening a new one. It seems that Wilczek says this experiment favors the many world's interpretation, but without having gone through the paper in detail, I'm guessing...

You have to look at the definition of a 'zone'. The further out from the center the light goes, the longer distance it has to travel, which shows up in the end on the screen as a phase shift of light, thus larger shifts the further out it went. The first zone is simply the light that is within...

Seems like what he chose now was Gregslist ;) (sorry couldn't help myself)

Also, keep in mind that population inversion should not be thought of as a temperature. The normal expression for temperature relates to to an average of an ensemble in equilibrium, but a population inversion is NOT in equilibrium. Even though you could still ascribe it a temperature it doesn't...