Recent content by wnvl2

No. In the meantime, I found the answer also in Contour Deformation, Pinches, and Causal Prescriptions. A Wick rotation is justified only if the integration contour can be rotated in the complex energy plane without changing the integral, except for any contributions that must be included. The...

In quantum mechanics and quantum field theory, Wick rotation is often used to transform oscillatory integrals into exponentially convergent ones by replacing real time with imaginary time. The result is then analytically continued back to real time. For example, a time-evolution amplitude...

In the paper, the experimental setup is asymmetric in the sense that the which–path measurement effectively takes place in only one arm of the interferometer. My question is whether, in a more symmetric configuration—where the momentum transferred by the electron is absorbed by the detector or...

Consider the standard double-slit experiment with photons (or massive particles), where a screen containing two narrow slits is illuminated by a coherent source and an interference pattern is observed on a distant detection screen. Assume that the slit screen is not rigidly fixed but is instead...

On a Dutch forum, there is a discussion about the following problem: A ##1 \mathrm{kg}## mass slides across a frictionless floor with an initial velocity of ##10\, \mathrm{m/s}##. The top surface of the mass has an area of ##1\, \mathrm{m^2} ##. The floor is perpendicularly irradiated with...

Assume the radiation is uniform in the emitter's frame. In that case, there is no acceleration in that frame. However, from the perspective of the ground, the radiation is not uniform. How can you explain that there is no acceleration in the ground frame?

HansH’s question is inspired by the following scenario: A cannonball is fired from reference frame 1 (the cannon). After a brief acceleration, it continues to move at a constant velocity relative to reference frame 1. Reference frame 2 is the frame moving along with the cannonball. Due to the...

A 1 kg mass slides over a frictionless floor at a speed of 10 m/s. The mass has a top surface area of 1 m². The floor is uniformly irradiated with an intensity of 1 W/m², and the radiation is perpendicular to the floor in the floor’s rest frame. All incident radiation is absorbed by the...

Do you mean that in most cases of lensing, the metric is not stationary, which results in the shifts generally not being the same? Otherwise, if the metric is stationary, wouldn’t that contradict what Ibix writes?

Can gravitational lensing serve as an example of a phenomenon where multiple paths are possible? How can I know in such a case that the frequencies from both paths will be the same?

I read most of Schutz and I know the lecture notes from Carroll. It is not that my understanding of general relativity is just based on chatgtp. I want to leave the spacetime geometry open. Limitations are that there is no cosmological constant and that the metric is stationary. The question...

Is the redshift of a photon between two events independent of the path? I assume for this question that the the cosmological constant is zero. Chatgpt writes: "In a gravitational field, the redshift can depend on the path taken by the photon. For example, in a Schwarzschild metric (which...

I think I understand it now better. I haven a system with 2 degrees of freedom ##\phi## en ##\theta##. The equations of motion are $$\frac{d}{dt}\frac{\delta L}{\delta \dot{\phi}}-\frac{\delta L}{\delta \phi} = -mg(a \sin \phi+l\sin\theta)$$ $$\frac{d}{dt}\frac{\delta L}{\delta...

I want to calculate the equation of motion of a planar pendulum of length l with a mass m at its end and a pivot point that moves uniformly along a vertical circular path (radius a) with a constant frequency ω. The Lagrangian and the equation of motion for a planar pendulum with a moving pivot...

I was a little bit in doubt after the reply from Gandalf on this topic here on stackexchange. Question was: "Since tensors are invariant under coordinate transformations, and a moving observer is just in another coordinate system, he should measure the same Riemann curvature tensor (with...