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Questions tagged [software]

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45 views

Runge-Kutta fourth order method. Integrating backwards [closed]

I am using a Runge-Kutta fourth order method to solve numerically the usual equation of motion of a background scalar field in curved spacetime with a quartic potential: $\phi^{''}=-3\left(1+\frac{H^{...
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0answers
30 views

Matlab code for plotting phonon dispersions [closed]

in matlab, i'm trying to plot the phonon dispersion across the Brillouin zone for a model of nickel aluminide, NiAl. Choose m1 = 59mp, m2 = 27mp, where mp is the mass of a proton, a = 2.88A, and ...
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0answers
23 views

Using FFT to find time-dependence of quantum mechanical free particle?

I am trying to visualize the time dependence of a free particle given an initial wave-function using Python and I just wanted to know if I could use the in built FFT implementation from NumPy to find ...
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0answers
58 views

How to calculate speed from time with changing exponential forces? [closed]

I'm making a physics-based game and I'm having trouble understanding how to implement exponential drag equations into an acceleration model so I can have a variable timestep between physics frames and ...
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0answers
26 views

Open source software or Matlab toolboxes for simulation of pulse chirping

I am trying to simulate the effect on the waveform of pulse chirping a Gaussian pulse from a femtosecond laser by various mechanisms (e.g. prism, grating, grism, fiber optical cables). I have tried ...
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0answers
16 views

Dispersion: any software to work out the dispersed waveforms of EMW signals that propagate via interstellar medium for some distance?

I asked this question in the Astronomy site, but seems few people feel interested in, so I hope to have a try here in the Physics site...... Is there any software (toolbox, code, package, paid or ...
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0answers
25 views

Verifying completeness of constants of motion

I can find constants of motion by looking at the null space of the Poisson Bracket operator $ \{H, \cdot\} $ over a polynomial space by brute force with symbolic algebra (code). This scales terribly ...
2
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1answer
63 views

Is there a program or a website able to perform all Wick contractions for a given expression?

Imagine I have an expression of the type: $$\langle \phi_{x_1} \phi_{x_1} \phi_{x_2} \phi_{x_2} \phi_{z_1} \phi_{z_1} A_{z_1} \phi_{z_2} \phi_{z_2} A_{z_2} \phi_{z_3} \phi_{z_3} A_{z_3} \phi_{z_4} \...
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0answers
29 views

A fast and automated way to check if symmetry (space group) operations preserve a lattice

Consider the simple cubic lattice. There are symmetry operations which preserve the lattice symmetry such as translations and rotations around certain axes. There are also symmetry operations that do ...
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0answers
37 views

Is there a “standard” quantum simulator/animator for pedagogy?

I'm having a hard time finding animations for 1D or 2D square well, SHO, free particle with barriers, etc, that I'm sure are "trustworthy". It's the sort of thing I would do in python in my spare time ...
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0answers
21 views

Fluid rendering technique (C++/3D) [closed]

I'd like to render fluid based on density value. Let's say I have a cube with 8 points (each of thoses points has its proper density value). So, If i want represent the fluid form on this cubic ...
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0answers
18 views

MCNP Summary Table

MCNP6 Version 1 produces a summary table of the results. Much of this table looks very useful, but I am not sure I understand the details. Here is an example. I'd be grateful for any hints about ...
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0answers
26 views

Visualising $n$-dimensional configuration space

I have recently studied in theoritical mechanics about the concept of of configuration space, which helps us understand the the configuration of a mechanical system by examining the curve traced by a ...
2
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1answer
29 views

Scattered fields in surface plasmon excitation with grating

We need to use prism-coupling (e.g. Kretschmann or Otto configuration) or use grating to excite surface plasmon between metal and dielectric. What I understand is that when we use a grating or ...
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0answers
34 views

Lippmann-Schwinger Equation (Numerical Method)

I recently tried to code up the numerical solution for solving the LS equation, which is based on the "scatt.py" code from R.H. Landau's "Computational Physics". The formulation is kind of like: $$ R_{...
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1answer
106 views

Master equation for the mechanical modes

Consider the standard model of optomechanical systems with a single optical cavity mode coupled to a mechanical oscillator, which is canonically modeled as a FP cavity with one fixed mirror and one ...
0
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1answer
49 views

Implementing the Hartree-Fock method in two dimensions from scratch

I am interesting in writing a complete code for the Hartree-Fock method to improve my understanding of it. It seems relatively complex in three dimensions, so I am wondering if it would be simpler in ...
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1answer
65 views

Resource recommendation for machine learning

I am planing to change my field (in PhD) and learn Machine Learning to differentiate different phases of strongly correlated matter. I learned Monte Carlo method in my MS and have intermediate level ...
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0answers
34 views

Fluid simulations on spherical coordinate grid: How to handle $\theta=0$ axis?

I am working on a fluid simulation code written in spherical coords. Whoever wrote the original didn't do a great job with the boundary conditions at $\theta=0$ and $\theta=\pi$ axes. My task is to "...
1
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1answer
143 views

Numerical Solutions for Equatorial Orbits in the Kerr Black Hole

Currently, I am trying to find timelike orbits in the Kerr metric around the equator. The problem is that no matter which parameters I choose or the method I use I can't seem to get to physically ...
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0answers
47 views

How to do Weierstrass-transform in MATLAB? [closed]

I have a diagonalization problem. I have the eigenstates correctly, and I want to do a Gaussian-smearing (Weierstrass-transform?) on them. So I have the wave functions ($\Psi$, $1\times N$ vectors), ...
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2answers
58 views

What software programs are recommended for background extraction and peak fitting?

I have an energy spectrum for various gamma sources. What software programs are recommended for background extraction and peak fitting in this case?
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0answers
31 views

Signal parameter estimation in PyCBC

I have a gravitational wave signal (strain vs. time). And I want to find out the corresponding parameters of the compact binary. But I do not know how to create injection for this signal in PyCBC. ...
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0answers
30 views

Mathematical software for calculating Christoffel symbols, curvature, etc [duplicate]

I'm looking for a Mathematical software that can do the following: I put in a metric (some kind of a two-dimensional matrix), and the software calculates Christoffel symbols, Ricci curvatures, ...
2
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2answers
77 views

Simulation software to solve high school level mechanics problems

I'm a physics teacher and I would like to find a simulation software that could be used to give exact numerical answers to high school level problems in Newtonian mechanics. I want the students to ...
0
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1answer
29 views

Wave-packet backwards emission

I am trying to reproduce the results of a TDSE two wave-packet algorithm described in "Computational Physics: Problem Solving with Python" by Landau, Paez and Bordeianu, in section 22.4 (Wave Packet–...
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0answers
55 views

“Data structure” for a fermion field

I am understanding the path integral formalism of fermion fields. Most textbooks told me that grassmannian integration is only algebaric notation. It shouldn't be understood in a Lebesgue Integral ...
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1answer
29 views

Is it possible to have discontinuities in the phase portrait of a dynamical system? If yes what does it really mean?

I've been using Mathematica to draw the phase portrait of a system and I got some jumps along the trajectory. I have a deviation term which might be the reason of this but is it possible to have them ...
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0answers
73 views

Numerically Solving EM problems. Book covering: ABS, PML, Near field calcul., LU fact, BicGstab, Pardiso etc

I looking for a book (or two) covering a range of topics: numerical implementation of boundary conditions (PEC, PMC, ABS); perfect matching layer; LU factorisation; numerical solvers and when to use ...
1
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2answers
98 views

Making sense of phase portrait of simple mass-spring oscillator

I'm new to physics, and I'm having trouble making sense of phase portrait of the following system, $$ m \ddot{x} + k x = 0 $$ whose phase portrait is in here. Since $$ x(t) = \sqrt{\frac{2E}{k}} \...
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0answers
147 views

$N$-body gravity simulator: why does energy conservation break down when introducing an adaptive timestep?

I am playing with an N-body gravity simulator using the velocity-verlet algorithm. In the actual simulation I normalize everything so that it is nicely behaved numerically, but I'll express things in ...
1
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1answer
119 views

Cross sections in Geant4 [closed]

Does anyone know where I can find the information about cross sections in Geant4? I would like to use my own file with cross section (exported from another code to MC simulations), but I cannot find ...
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1answer
100 views

Can anyone tell me how can draw shadow of black hole like in presented in Intersteller movie? Is there any code for it in Mathematica or in Python? [closed]

Equation of motion for photon $$ \Sigma \frac{dt}{d\lambda} = aL\left(1-\frac{r^2+a^2}{\Delta}\right) + \omega\left(\frac{\left(r^2+a^2\right)^2}{\Delta}-a^2 \sin ^2\theta\right)\ , $$ $$ \Sigma\frac{...
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0answers
21 views

Program for calculating transition amplitudes

I calculated transition amplitudes with MBPT analytically and used Slater-Condon rules. Now I have a very long expression and I would like to solve my matrix elements. Does someone know a program for ...
1
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1answer
63 views

Math notation for heating object

An object with mass $m$ and heat capacity $c_{p}$ is exposed to heating $P_{th} $[kW] and thermal losses $\dot q$ [kW/°C]. The energy equation illustrating the process of heating it from $T_{max}$ to $...
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0answers
27 views

Is there a mass spectrometer software that can measure the mass of a hydrogen atom [duplicate]

For a school project I need to measure the mass of a hydrogen atom either as a lab experiment or with a computer simulation. Since I don't have the appropriate equipment for the experiment, does ...
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0answers
51 views

Is there a mass spectrometer software that can measure the mass of a proton

I spent a lot of hours looking for mass spectrometer software (or Cathode-ray simulator) that can measure the mass of a proton or any sub atomic particle. Until now I only found software that work on ...
1
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2answers
283 views

Implementing a spherical pendulum

I am trying to implement a spherical pendulum. The Lagrangian (which I haven't fully understood so yet) based on $l$, θ and φ taken from this page result in the equations: \begin{align} \...
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0answers
76 views

Why does conservation of energy appear to be violated? [closed]

I am currently working on a rigid body simulator. Before getting proper collision and rotations working, I decided to simulate the collision of spheres as axis-aligned objects. The simulation works ...
0
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1answer
154 views

Is there a general algorithm for conversion of units?

I'm not exactly sure where the best place to put this, as it's more of a general question about dimensional analysis. I decided I was tired of having to convert units all of the time, and was not ...
1
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0answers
56 views

Collision response with spring physics in RK4

I'm trying to figure out what's in the title. I've gotten regular spring physics working and now I'm trying to do something similar with actual collisions (player character colliding with the ground ...
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0answers
27 views

Where can I find an interactive vector field?

Imagine a low-pressure system as a vacuum that sucks all the surrounding air straight towards it, creating many vectors of wind that all focus on one spot. Because of the Coriolis effect, each of ...
0
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2answers
58 views

How to animate a ball rolling down an incline?

I'm using Lagrangian mechanics to come up with the equations of motion for a ball rolling down an incline. I've come up with the following two equations. $$\begin{alignat}{1} \dot{x} &= \frac{2}{...
2
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1answer
58 views

Visually and physically reasonable analytic approximation to the field of a bar magnet

I want to produce publication-quality drawings of the field of a bar magnet, in both the field line representation and as a "sea of arrows." I've found some open-source software that looks like it ...
1
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1answer
117 views

Weird results of Monte Carlo simulation

I'm simulating the 3D Ising Model using the Wolff update algorithm. I am using the Mersenne Twister RNG. When the lattice size is $L = 50$, the specific heat curve looks very weird!! I want to ...
3
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0answers
154 views

Is there an alternative to SIMION?

Is anyone aware of an alternative, possibly open-source, to the SIMION software? From their website: SIMION is a particle optics simulation software primarily used to calculate electric fields ...
1
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0answers
145 views

COMSOL magnetic field time dependent [closed]

enter image description here I need to modelling conductor in Comsol 5.3 by MF physics in Time Dependent study Conductor model "Single conductor" in "Coil" feature doesn't work in TD study, and ...
3
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1answer
67 views

Laplace's heat equation equilibrium functions

I simulated the Laplace's heat equation on a grid (200x200) with boundary conditions of 0 (a cold source) on the top and left and 1 (of hot source) on the bottom and right. (see gif) I stopped ...
1
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1answer
158 views

How to improve this simple Brownian motion simulation by adding viscosity?

I've written a 0th order Brownian motion simulator to envision how a particle of smoke might appear to move under a microscope. There will be missing $\sqrt{2}$'s and $\frac{\pi}{2}$'s since I haven'...