Recent content by Cthugha

You mean like when you do not only consider Gaussian spatial modes,but also more complicated Laguerre-Gaussian modes carrying orbital angular momentum and possibly also their superpositions? Yes, I fully agree. The relative phases appearing there are very relevant. I just intended to point out...

The (mean) phase ##\langle \phi \rangle## is the argument of the complex amplitude ##a## of the light field, where ##a## is the complex value you get by applying the photon annihilation operator: $$\langle \phi \rangle=arg \langle a \rangle=arg (Tr(\rho a))=arg \left( \sum_n \sqrt{n+1}...

Okay, I see your point, but I did not (and I think I still do not) interpret these posts in the way you do. Taking into account that for these states a description in the photon picture is harder than the classical one, I considered "useful description" to mean a description that adds to the...

It was the great achievement of Roy Glauber (and also George Sudarshan) to come up with a framework that gives an absolute meaning to the word coherence. First-order coherence (as seen in the double slit or a Michelson interferometer) is indeed bandwidth-limited. First-order temporal coherence...

Mostly alright (although thermal sources may feel treated unfairly ;) ). I tend to disagree about the uncertainty part. Especially for thermal light, this is a consequence of thermal equilibrium between the photon gas and the walls of the emitter. For thermal light, this is not really due to an...

This statement is unfortunately incorrect. Already if you put a single coherent beam into a beam splitter, the output state considering both outpuut ports is a tensor product state. You trivially see interference between these two output beams. You need, e.g., a mixed state, where the...

No, why should it? In a standard laser, you also cannot distinguish between photons coupled out of the resonator at some moment and photons coupled out exactly one round trip later. One would also not consider this a multi-photon effect. It just matters whether all the excitations are within a...

No, this is what Glauber is of course famous for, but this is not what he is referring to. The key point is that all completely indistinguishable events that begin from the same initial configuration and end up with the same physical situation (which in this case means a detector click at some...

Yes, absolutely!

That is incorrect. Also, the experiment shown is not the double slit with single photons, but a double slit experiment done with a light field of an intensity of less than one photon on average. This is a huge difference. Nobel prize winner Roy Glauber phrased this nicely (see this text on the...

Well, as long as there is some lower energy state available in principle, then decay is in principle also possible. For example, for quite some time bismuth was considered to be the heaviest stable element until some experiment (See this article) demonstrated a very slow decay with a half-life...

In a nutshell, that is alpha decay.

That is a false friend because it looks mathematically correct, but is interestingly not related to the physics at hand here. Usually, the second expression is considered the correct Q factor. There are several surprisingly nontrivial factors involved here. First, for a sinusoidally driven...

Michelson interferometers, Mach-Zehnder interferometers (and also the double slit) measure field correlations. The quantity you measure in the end is of course an intensity (because this is how detectors work), but you delay or offset one field in space or time and quantify the correlation...

No, your calculation seems about right. There is no layer thickness involved in this calculation. Usually you get the transmitted intensity I through a system of thickness d by calculating: $$I=I_0 e^{-\mu d}$$. However, you mentioned that your nanoparticle supplier gave you some particle...