# Questions tagged [computational-physics]

Questions with this tag should be about computational physics, which is the study of physical situations with the use of software (commercial or in-house). Please note that details of writing and/or debugging code is OFF-TOPIC and should be asked at either Computational Science, Code Review or Stack Overflow.

1,637 questions
Filter by
Sorted by
Tagged with
42 views

### Superposition states in an infinite square well

I'm trying to simulate superposition states in an infinite square well using Python, but my results don't match those from a web simulation. I'm using the wavefunction and energy level functions ...
22 views

1 vote
44 views

### Difficulty solving conformal-bootstrap-like crossing equations using semidefinite-programming (SDP) via SDPB software

My question involves semidefinite programming (SDP) in the sense of attempting to find some vector $\alpha^{\mu}$ that satisfies the following conditions: Normalisation: $\alpha^{\mu}n_{\mu} = 1$ ...
28 views

### Why am I wrong when calculating the atomic system's stress?

Assume a static non-periodic-bounday-condition $N$-atom system in a cuboid box only have potential energy $U$, which is merely the function of all atom positions, i.e., $$U=U(\{{r_i}\}) \tag{1},$$ ...
• 253
51 views

### CFD Boundary condition: Pressure far field vs Pressure outlet

I’m confused about a Pressure far field and Pressure outlet boundary condition Should I be using a pressure far field (for the ‘outlet’ of the computational grid) instead of pressure outlet? Flow is ...
39 views

### Nuclear level densities and neutron stars

My current PhD. project involves working with nuclear level densities (NLDs). However, I am more interested in the applications of NLDs to astrophysics. I know they are important to in calculations of ...
75 views

### What numerical methods can be used to verify the accuracy of Feynman diagram results?

Recently, I have been attempting to replicate the Feynman diagram calculation which was featured in an article here. \begin{align} &C_{x y x y}^{1, e}(i \Omega)= -(1-\delta) r_0^{-\delta} 2^{4+\...
• 21
1 vote
129 views

### Solving Poisson equation for galaxy rotation curves

Can someone point me to the numerical methods to solve the Poisson equation for the galaxy rotation curves? I've heard of some tools like PETSc or OpenFOAM. But I'm not sure if these are the right ...
• 859
60 views

### How does numerical simulation of GR work in the case of closed timelike curves?

In all cases I'm aware about so far, when you want to do a numerical simulation of a physical system, you invoke the initial conditions and program how the system evolves in time. Now presumably, I ...
• 6,437
30 views

### Potential field in inhomogeneous conductor boundary conditions for Finite Volume Method

I have a question on how to represent a region of perfect conductance in a finite volume method solving the potential field inside a domain. To ask the question I will first explain the full situation....
• 1
125 views

### Geodesics: Energy functional vs length functional

The Wikipedia article about geodesics talks about the equivalence of obtaining the geodesic by either minimizing the length functional $L$, or by minimizing the energy functional $L^2/2$, cf. the Phys....
47 views

### What happens with tight boundary conditions in the V-CYCLE while doing numerical Electrodynamics

My problem is very simple to understand. We are trying to solve the Laplace equation in a domain that has sufficient boundary conditions to converge to some solution. Our example is this. 2 ...
1 vote
86 views

### Statistics error limit on a fitting

We are trying to analyze gamma-ray spectra that come from a neutron scattering in the soil sample. Our hope is to find the final error in the fitting parameters of the peak, which should look like a ...
• 11
37 views

### Gravitational acceleration in my acceleration data (IMU)

I am trying to do gait analysis and remove gravitational acceleration ($9,81 m/s^2$) from my data. I have used IMU (on the patient's lower back) to record acceleration, angular velocity and roll/pitch/...
20 views

### Nonequilibrium Greens function via a DMFT-mapped Anderson model?

Let $H = \sum_{<i,j,\sigma>}t_{i,j}c^\dagger_{i,\sigma} c_{j,\sigma} + h.c. + U \sum_i n_{i,\uparrow}n_{i,\downarrow}$ be a standard Fermi-Hubbard Hamiltonian. Let us single out one site of the ...
28 views

• 91
1 vote
80 views

### Why does Ronald Ruth integrate momentum as velocity in his 1983 paper "A canonical integration technique"?

I am trying to apply a time integration technique for a system of discrete particles using Hamiltonian symplectic mechanics. In his relatively well-known paper (CERN,PDF) on symplectic integrators, ...
71 views

### What are the advantages of tensor network algorithms over monte-carlo simulations in terms of time-evolution?

I understand that tensor networks and monte carlo simulations are based on completely different principles. However, to my knowledge both are used to simulate the time evolution of a system. Is there ...
• 91
1 vote