For which circuits will KCL and KVL be applicable?

I was looking at this experiment by Veritasium. https://www.youtube.com/watch?v=a8FTr2qMutA&t=4s Here he shines a green light through a narrow slit and we see the light smear as the slits becomes narrower. Momentum of a photon is ℎ𝜆. Since ℎ is a constant, shouldn't the uncertainty in momentum m...

In quantum field theory electrons are conceptualized as quantized excitations of the quantum electron field. Generically the electron field can be in a superposition of number states. This is related to the fact that under QFT Hamiltonian/Lagrangian energy can be exchanged between electrons and o...

Ohm’s law states that the voltage across a resistor is directly proportional to the current through. This is given by the formula v=iR. But most textbooks say that this law is violated when the v vs i graph is nonlinear. However, at each point along the graph of a non linear resistor, v=iR holds,...

A typical simulation of lattice quantum chromodynamics uses imaginary time, so the weight function of the path integral is positive definite $e^{-S_E}$. In the case of metropolis-hastings, the algorithm is basically: Initialize the field with random numbers from a normal distribution Pick a rand...