Recent content by neworder1

Homework Statement Ideal dielectric gas is in a container closed by a movable piston and in thermal contact with its surroundings, so is kept at constant tempertaure T_0 and pressure p_0. Inside there is a capacitor with fixed voltage and total electric field E. The gas has permittivity...

What is the most general reasonable form of the Lorentz invariant interaction term between a fermion field \psi and a scalar field \phi? A common choice for the interaction is something like \psi^{\dagger}A\psi\phi, with A being a Lorentz invariant matrix (like \gamma^{5}). However, I don't...

The algebraic formulation of quantum mechanics (and related stuff, like quantum thermodynamics & dynamical systems etc.) via C*-algebras provides a viewpoint based mostly on abstract functional analysis. However, I've yet to see a working application of this approach, i.e. an example of a...

Quasi-classically, a photon is often considered as a particle with some momentum traveling across the space - for example, when describing experimental setups like Mach-Zender interferometer we often talk as if the photon was actually a particle moving along some possible paths, i.e. we treat it...

Rotating an electron by 360 degrees causes its spinor to flip sing (\vert \psi \rangle \rightarrow -\vert \psi \rangle). Has this effect been observed experimentally (e.g. in an appropriate modification of the Stern-Gerlach experiment)?

Sorry, I think I don't get something here. After my partner's measurement, the joint state of the system of all four particles is either \vert 01 \rangle \otimes \vert 10 \rangle or \vert 10 \rangle \otimes \vert 01 \rangle . If I don't know his measurement's results, I only know that with...

Correct. On purely computational level, gaining knowledge of my state turns my initial totally mixed state into some pure state. However, I think I don't quite understand the physics here. There is no interaction with macroscopic devices or anything that would constitute a "measurement"...

I have the following conceptual problem with the quantum effects of (in)distinguishability of particles: Imagine the following experimental setup. I have two pairs of entangled electrons, A1, A2, B1, B2 (i.e. A1 is maximally entangled with A2, and so is B1 with B2). The spins of all electrons...

Ad. 1. When trying to determine possible energy values, we look first for a separated solution to the Schrödinger equation, i.e. solution of the form \psi (x, t) = \Psi (x) \phi (t). If the Hamiltonian H is time-independent, separation of variables proves that H\Psi = E\Psi for some constant E...

I don't know what the author meant, but my guess would be: - since the well has finite width, the uncertainty in position is always finite, i.e. \Delta X < \infty - now, if you take time-independent Schroedinger equation H\Psi=E\Psi \Leftrightarrow \frac{\partial^2 \Psi}{\partial...

Prove the following result: let G be a compact Lie group, H its closed subgroup and X = G/H. Let T(X) denote the space of G-invariant differential forms on X (e.g. \omega \in T(X) \Leftrightarrow \forall g \in G g^{*}\omega = \omega). Then T(X) is isomorphic to H^{*}(X), de Rham cohomology...

Ok, but in the noninteger case the solutions are special functions, from which I don\t know how to calculate the phase factors in question.

Homework Statement Use partial waves method to calculate scattering amplitude for a quantum particle scattering off the potential V(r) = a/r^2. Homework Equations The Attempt at a Solution To calculate phase shifts \delta_{l} for each angular momentum's value l, it's necessary...

That's incorrect, because <L^2> = l(l+1), not l^2.

We cannot assume that \psi is the eigenstate of L_{z}. All we now is that it is some eigenstate of L^{2}.