Recent content by otennert

Are you mixing this up with something else maybe? I only know the term "wavelet" in the context of signal analysis / engineering. Definitely the term plays no role in the context of what you are asking in the first place.

I think we have covered the "time-energy uncertainty relation" a couple of times already, see e.g. here: https://www.physicsforums.com/threads/time-energy-uncertainty-relation.1046138/post-6807748

No it doesn't, correct.

No, that's wrong then. A test particle does of course get "swallowed up" (forgive the colloquialism), and a white hole does get "ejected". A test particle by definition just does not show backreaction.

Correct, otherwise they wouldn't be test particles, but would rather enter the material stress energy tensor in the rhs of the Einstein equations.

I am not quite sure if I understand your question correctly. Of course, the whole area here is "no quantum" whatsoever, only classical GR. By accretion you mean a particle crossing the Schwarzschild horizon? What quantity do you refer to by "0"?

Let's start with what I think everybody agrees with here: the Schwarzschild spacetime is static in the asymptotic region "I". Hence there is a time-reversal symmetry ##t\mapsto -t##. The Kruskal spacetime has the same symmetry ##t\mapsto -t##, although it must not be called static in the...

My take: $$\hat{A}(-x,-t) = \left.\frac{d}{dx}\right|_{-x} + f(-x,-t)$$ Unless the function acted upon by ##\hat{A}(x,t)## possesses any symmetries, I'd say neither of your suggestions are correct.

First of all, we are not talking about linearized GR, right? In GR and in generally curved spacetimes, the problem actually begins earlier, i.e. in the definition of a "plane wave" per se, and in a coordinate-free manner. The resolution is given in early papers by Ehlers and Kundt 1962, and a...

This one I own too, but I haven't read it yet. I would say it is comparable in style and content.

I haven't read them (yet), but they are at the top of my list. However, I have read this one: https://www.amazon.com/Conceptual-Framework-Quantum-Field-Theory/dp/0199573263?tag=pfamazon01-20 and in a way the books you mention above are the prequels to it. They are not typical textbooks on...

In scattering theory, when you consider the so-called (complex-valued) Jost functions ##F_l(k)##, the dispersion relations relate the real and the imaginary parts of ##F_l(k) -1##. And the specific form of these relations make each the Hilbert transforms of the other. Just google for Jost...

Thanks a lot Florian! Actually, it is currently being translated into English, but don't expect the volumes to be out before mid of 2025... Cheers

Indeed! Well, at least that's what the usual procedure would require...

Absolutely: it is much too often not mentioned that field operators are operator-valued singular distributions, hence the infinities occurring in QFT are the result of exactly this "sloppy" use and must be dealt with by the renormalization programme. However, as dirty as it might look, it works...