# Tagged Questions

Quantum mechanics describes the microscopic properties of nature in a regime where classical mechanics no longer applies. It explains phenomena such as the wave-particle duality, quantization of energy and the uncertainty principle and is generally used in single body systems. Use the quantum-field-...

16 views

### Fermi's theory of beta decay - density of states?

I am following through these MIT OCW notes on Fermi's theory of beta decay. On page 11 (103 as on page) they wrote the expression: $$\rho(p_e)dp_e = dN_e \frac{dN_{\nu}}{dT_\nu}$$ for the density of ...
11 views

### Find the energy of an x-ray photon which can impact a maximum energy of $50~\mathrm{keV}$ to an electron [on hold]

This is an exercise question from the text book Concepts of Modern Physics by Arthur Beiser. Find the energy of an x-ray photon which can impact a maximum energy of $50~\mathrm{keV}$ to an ...
15 views

### how time is related to gravity? [on hold]

favorite 2 My question is regarding the following Gauged Linear Sigma Model (GLSM) in two dimensions. S=∫d2x(−Dμϕ¯¯¯Dμϕ+D22e′2+D(|ϕ|2−r)).(1) Here Dμϕ=∂μϕ+iQAμϕ, D is an auxiliary field, and e′ is a ...
41 views

### Does angular momentum of hydrogen atom imply motion of electron around the nucleus?

Does the non-zero orbital angular momentum (or z-component of angular momentum) of a stationary state of hydrogen atom imply motion of electron (or at least the probability density $|\Psi|^2$) around ...
30 views

### Invariance of a maximally entangled state under unitary operation $U \otimes U^\dagger$

Apparently the (d-dimensional) maximally entangled state, $|E \rangle = \sum_{i} |ii\rangle /\sqrt{d}$ is invariant under operations of the form $U \otimes U^\dagger$. I want to prove this result, ...
24 views

### Matrix elements for graphene

I study graphene. Now I have to get matrix elements from its wavefunction. My problem is that I've got the wavefunction in exponential form. For instance, I get something like \...
20 views

### Derivation of expression for Berry curvature

Many texts quote the expression for the Berry curvature for a two-level system, with Hamiltonian $\mathbf{h}(\mathbf{k})=(h_x,h_y,h_z)$ in terms of $\mathbf{k}=(k_x,k_y)$, as something like \begin{...
16 views

### Is there a verified physical balance in the Maxwell source terms derived from QM Wavefunctions [on hold]

In QM one construct the charge and current source distributions for Maxwell equations, seen in standard textbooks on quantum mechanics, so that the external EM field can be calculated. A nice feature ...
23 views

### Is there scattering event if two wave functions overlap in momentum space?

Let's consider two particles, moving, for simplicity, in a 2D plane, represented by their wavefunctions in the form of (when being modulus squared) very very very narrow Gaussians (let's say close to ...
41 views

64 views

### Can the Copenhagen interpretation and the many-worlds theory be somehow reconciled? [on hold]

Is it possible that, at the moment of observation, a timeline is created where an object is in a state which contrasts its state in the current timeline? Using Schrodinger's cat as an example, let's ...
49 views