Subdiscipline of theoretical physics which consists in the study of physics problems using numerical algorithms. PLEASE NOTE that questions about computational methods and/or programming are OFF-TOPIC on Physics.SE.

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How do we define capillary number in 2D (two dimensions)

In 3D the capillary number $Ca$ is defined as: $$Ca=\frac{\nu \rho U}{\gamma}$$ where $\nu$ is the kinematic viscosity ($m^2/s$), $U$ is the velocity ($m/s$)and $\gamma$ is the interfacial tension ...
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62 views

Possibility of simulating quantum physics and relativity [closed]

I must be clear; this is not a 'specific' question, but rather a hypothetical one. As of now, computer physics simulations are becoming more and more advanced, and I am programming one now. I was ...
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1answer
60 views

Broken Thin Lens Algorithm [closed]

We all know the thin lens equation. For $o$ being a horizontal object distance and $f$ being the focal length, the horizontal image distance $i$ is described by: $$\frac{1}{f} = \frac{1}{o} + ...
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2answers
36 views

Correlation energy - is it the difference between the Hartree-Fock energy and exact energy, or Hartree-Fock PE and exact PE?

For some reason I can't find anything stating it either way explicitly. What I'm talking about is this. Is this difference referring to potential energies or just energies in general? I assume it's ...
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50 views

Force Needed To Maintain Velocity, Increasing Mass

Hoping somebody could give me a hand with this. Unfortunately I haven't taken physics yet, my background is in math/computer science. I'm studying computational science and the problem is essentially ...
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1answer
31 views

Amount of unknown parameters in compressible Euler equations

I'm looking at this page for the compressible Euler equations. To me it seems, in the 1-dimensional case, there should be 3 unknowns: density, velocity, and pressure. This is because the energy $E$ ...
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1answer
62 views

Probability density function of a particle for computation [closed]

I'm writing a program, part of which relies on a particle being able to change location similar to a how a real particle would behave (pardon my physics). For example, on a grid of 100x100, a ...
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216 views

My python trajectory calculator for a small mass in a gravitational field - why is energy conservation violated?

I wrote this thing to calculate the next position of a small mass, given its current position and velocity, and a vector field determines acceleration. It sort of works - except I can never get the ...
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1answer
47 views

Ideas for physics-related simulations to code up as weekend (or monthly) projects [closed]

What are some good ideas for simulations that I could try to implement/code in my spare time just for educational purposes? I'm thinking that it would be a good way for me to delve into the underlying ...
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1answer
155 views

Physical simulation in python [closed]

Is there a "standard" python package used to aid in physical simulations? What is the most popular? edit: perhaps I should have worded this question differently. Something more to the effect: Could ...
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1answer
127 views

Monte carlo simulation for continuous spin model (e.g. XY or Heisenberg model)

Unlike the Ising model, the XY model and the Heisenberg model have a continuous spectrum. So one need discretize them for a numerical simulation. But how to make sure the discretization procedure ...
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1answer
79 views

Failure of a simple stat mech simulation

so I did a simple simulation that I thought would yield a Boltzmann distribution, but it failed to, and I was wondering if anyone has insight into why it failed. Ok, so I had a simple discrete system ...
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1answer
155 views

Reference-request: Computational science and physics [closed]

I'm interested in the following question: Is Nature computable at it's most fundamental level? Can anyone suggest any works (books, papers / articles, reviews) related to the above question? ...
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1answer
176 views

Filtering and extracting turbulent data from instantaneous dataset

I have collected data on flow velocity at 1 Hz sampling rate for 25 hours using a high resolution acoustic Doppler current profiler (HR-ADCP). how I can decide up to which period is the mean ...
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0answers
33 views

What exactly is closed orbit theory and what assumptions go into it?

I am just beginning a research project on the study of closed orbits, specifically as related to hydrogen, and I wanted a little bit more information on what exactly makes something a "closed orbit". ...
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0answers
16 views

Graphene plasmonics, Integro-differential eigenvalue equation [on hold]

In my research around plasmonics in 2-Dimensional nanostructures like graphene, I encounter an eigenvalue integro-differential equation of the form: ...
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2answers
58 views

What is the fastest algorithm to solve a Nonlinear second order differential equation numerically

I am trying to solve a second order non linear differential equation in one variable. Using RK4 I am getting good accuracy and is working fine. But the problem is my range is very high so it will ...
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0answers
25 views

Mechanics - Rotational Inertia [migrated]

I am facing a problem solving a mechanical system which is shown in the scheme below. We assume that coupling of the two shafts is done with a clutch Equations: ...
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0answers
30 views

What is the largest atom with a reliable configuration-interaction (CI) calculation?

The simplest approximation for calculating the ground state of an atom is the Hartree-Fock approximation. To get accurate result for the ground state energy, one has to do configuration-interaction ...
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26 views

Q: Any standard terminology for “gold standard” Monte Carlo solutions

The "standard" way in our field to compute scattering statistics in wave propagation problems is via a "deterministic" wave prop code operating in a Monte Carlo context where we iterate over many ...
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0answers
21 views

What is the difference between finite displacement and linear response for calculating vibrational properties?

I see these concepts appearing in the context of calculating phonons and other vibrational properties, but I can't find a concrete explanation of the differences between linear response (DFPT) and the ...
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1answer
52 views

Using the Fourier transform to find the natural frequencies of coupled oscillators

How can I find the natural frequencies of a system consisting of a pair of coupled oscillators using Fourier transforms? The System consists of two masses and three springs. One of the springs ...
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0answers
42 views

Ising Model 2D Correlation Length

I'm using Metropolis and Wolff Clustering algorithms to estimate the spin-spin correlation function $$<s_os_r>$$ I know that this is related to the correlation length but how do we determine ...
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39 views

Why are functional representations of systems important in physics or computational physics?

This was an addendum to a previous question I asked, but I figured I should make it it's own discussion. Assuming I am able derive a functional representation for any dynamical system (dissipative, ...
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1answer
82 views

Leapfrog method in Particle-in-cell

Recently I wanted to write a 3D electromagnetic Particle-in-cell code with c++.I know that I should use leapfrog method.For example,when I calculates the position and velocity of particles,i should ...
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18 views

Why breakdown voltage decreases with increasing FWHM of an asperity?

I am running a simulation for a dielectric breakdown. I am getting breakdown voltage decreases with FWHM, which does not make sense as field enhancement is higher for a small width. Simulations solve ...
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1answer
30 views

2D room with electron-point-charges (stability)

Is there a fast way to find out stable #"point charges" & constellation for this kind of Simulation. The 2D repeating itselve in each direction till infinity, so i've a kind of symetrie here. ...
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24 views

Optimize locations of vertices and edge length using physics without simulation

I have a directed graph with set of vertices and edges. Each vertices don't have a position coordinate to be displayed on 2D computer screen. I want to add unique position coordinate to each vertices ...
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25 views

Adams-Moulton and BDF methods

1.What are the differences between Adams-Moulton and BDF methods. Which one is better and which one computes the solution faster? I think Adams-Moulton is a better method as it can get to the ...
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68 views

How to calculate a Mooney-Rivlin material

Well, I'm working on a fsi (fluid-solid/structure interaction) model. I've got ready the fluid part, now I need to get ready the solid part. Since I'm working with tissues, I need to use an ...
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38 views

need some references in molecular dynamics simulation

I Just start we a new model on my project and I will need to work with Molecular dynamic simulation. I have to simulate dynamics of many filament inside a network (actomyosin network).The problem is ...
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1answer
198 views

Position based dynamics constraint scaling factor

Reading through Müller et al., Position Based Dynamics, 2007 I got lost when passing from equation (5) $$\Delta p = \frac{C(p)}{|\nabla_pC(p)|^2}\nabla_pC(p)$$ to equation (6) (and applying the ...
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0answers
26 views

Electron scattering with CSDA simulation

I am currently in the process of writing simulation code for a "computational physics lab course" and in the present case the task is to simulate the trajectories of 20 [MeV] electrons impinging on a ...
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49 views

Examples of application of detour matrices in physics?

Are there any good examples of application of detour matrices in physics?
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45 views

Poisson equation solver with specific boundary condition

I want to solve 2d Poisson equation with this Boundary conditions below $$u(-5,y) = 0 , \\ \frac{\partial u(x,y)}{ \partial x} = 0 \,\,{\rm at}\,\, x = -5\\ u(x,-5) = u(x,5)$$ Now my question is ...
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0answers
26 views

Verlet timestep

I am using velocity Verlet in molecular dynamics. Is just a simple question, if a simulation using time-step femtosecond, in velocity Verlet is just necessary $dt = 10^{-15}$ to use femtosecond?
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0answers
27 views

Computational package to find the ground state of a particle in 3D domain [duplicate]

I am developing a numerical algorithm to find the ground state of a Hermitian matrix. Obvious applications are quantum many-body systems and particles in various potentials. I am a little stuck with ...
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0answers
81 views

Need help simulating a fan

I'm trying to write some code to approximately simulate a number fans in an arbitrarily shaped room. I'm not real strong in physics, and could use some help. If it helps I'm not interested in fine ...
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1answer
110 views

How to Extend Relaxation Methods for 2D Laplace Equation given in Jackson E&M to 3D?

In Jackson (3 ed) chapter 1.13 an outline is given for using relaxation to solve laplace equation in 2D. The general procedure in 3D involves minimizing the quantity $$I[\Psi]=\frac{1}{2}\int_V ...
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0answers
43 views

Should particles in Smoothed Particle Hydrodynamics (SPH) always move during a simulation?

Or can they just be used as an interpolation points and use some other "transported property" which are just evolved and propagated from boundary conditions like for eg. heat conduction through a ...
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1answer
127 views

Plane Wave expansion method

I really don't know if this is the right forum to ask the question...but please help me if you can!! I was going through the Plane Wave Expansion Method Derivation...But to be honest I could not find ...
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0answers
64 views

Can peridynamics give accurate quantitative results?

I'm applying for a position that is interested in studying crack growth using peridynamics. I have experience with MD on polymeric systems, but I had never knew of this method before. It seems very ...
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89 views

numerical diagonalisation comparison of complex Hermition matrix and real matrix

we are doing K space calculation(transnational invariant basis) of Hamiltonian, and trying to compare with exact method for same nos of sites and particles, we are getting big difference in ground ...
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1answer
134 views

I am looking for 'Programming+Electronics+ Physics' field [closed]

I wish to pursue a career that somehow involves programming, electronics, and physics. What are such careers? Also, I have heard of some 1 year post-graduate diplomas/courses for specialization in ...
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2answers
84 views

Standards for scientific metadata in common-use image formats? [closed]

I have a bunch of JPEG, JPEG2000 GIF and PNG files that in theory could be used for some types of science analysis if there were temporal and spatial information in them. Years ago, I had looked into ...
-2
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1answer
48 views

Software for calculating the trajectory of a body in a coordinate system

I'm looking for a program, which would simulate the path of motion of a body in a coordinate system, given the force acting upon the body. I'd type in the initial conditions such as the velocity, ...
-2
votes
1answer
136 views

Can you suggest me some good resource for learning Mathematica for physics? [closed]

I am into HEP. I know nothing in Mathematica and have to start from basics. HEP requires a lot of computation for Feynman diagrams etc could you please suggest some good resource to start learning ...
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1answer
69 views

Computational physics using mathematica [closed]

So I was confused about this question on how to exactly begin to answer it. I am a novice in mathematica and I am teaching myself thus I require help in this question. From what I think I should do, ...