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Questions tagged [physics]

Questions related to the application of Mathematica to problems in physics.

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0answers
865 views

How best to simulate n-body systems in a functional way

I want to simulate a N-body system in the most functional way possible. The system I'm modeling are metallic colloidal particles in a solution of peroxide water, as here http://arxiv.org/pdf/1502....
7
votes
0answers
249 views

How to use periodic boundary conditions on the derivative of u[x,y,z]?

I have a structural mechanical problem, where i try to calculate the strain field in the modelled material. I simplified the problem in the following example: There is a material with two phases, ...
6
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0answers
333 views

Mathematica packages for numerically solving the Klein-Gordon and Dirac equations?

The book "Advanced Visual Quantum Mechanics" by Thaller includes Mathematica software packages for the numerical solution of the Klein-Gordon equation and the Dirac equation (subject to user-defined ...
4
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0answers
278 views

Is it possible to use Gaussian cgs units in Mathematica computations?

I was trying to do computations in Gaussian cgs units, and of course I failed due to dimensional issues. For instance, $q_1 q_2/r$ cannot be converted to $\mathrm{erg}$ since Gaussian system uses $4\...
3
votes
0answers
100 views

Stationary 1-D Schrodinger equation for calculating energy of a -CH3 group quantum rotor in a metal organic framework

I am trying to calculate the energy of a quantum mechanical rotor by plugging a potential function predicted from DFT calculations in this paper: DOI:10.1039/C8CC02650E The potential can be ...
3
votes
0answers
56 views

Sneg Library - Number operator simplify

I am trying to use the SNEG Library for evaluating some commutators. For instance I am trying to evaluate $$ \left[n_1^2,a^\dagger_1\right]$$ with the code in Mathematica ...
3
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0answers
230 views

Presentation of SNEG creation and annihilation operators in Mathematica 11

I am using the Mathematica package SNEG to make some calculations in solid state physics (see http://nrgljubljana.ijs.si/sneg/). The programs in SNEG library are running, but their presentation are ...
3
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0answers
129 views

Finding possible lattice planes of a crystal structure

After generating a crystal structure from a crystallographic data and duplicating it to a larger crystal system I would like to find possible lattice planes of this crystal. It is well-known that the ...
3
votes
0answers
355 views

Solve PDE over time-dependent region

I have some experience with C++ programming, but I am quite new to Mathematica and I think the latter requires a different mindset which I am still not used to. I would like to simulate the effect ...
3
votes
0answers
198 views

Differential equations in partial derivatives

I am trying to get numeric solution for equations: $$ \left\{x^{(2,0)}(u,t) \left(1-\frac{y^{(1,0)}(u,t)^2}{\left(x^{(1,0)}(u,t)^2+y^{(1,0)}(u,t)^2\right)^{3/2}}\right)+\frac{x^{(1,0)}(u,t) y^{(1,0)}(...
3
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0answers
245 views

How can I improve the solution of my PDE?

I want to improve the last code to find a better solution for umi. For now I'm using only MaxStepFraction. Also, when I put no ...
3
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0answers
158 views

How to control pedestrians to enter the simulation region with random functions?

I am working on simulating crowds of a cross-typed region, given that pedestrians entering from 4 gates of north, east, west and south, ...
3
votes
0answers
669 views

Visualising Special Relativity

Mathematica newbie learning by doing (or not so far, in this case). Problem: Special Relativity - consider two inertial frames $A$ & $A'$ in relative motion. At a time $t0$ as measured in $S$, ...
2
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0answers
43 views

Symbolic perturbation expansion for quantum mechanics using Hellmann-Feynman derivaties

I am interested in some quantum mechanical perturbation expansion for energies. Actually I want to implement these terms $E_n^{(k)}$. As is stated below one can do that using CAS. I would be ...
2
votes
0answers
51 views

Antiparticles in Feynrules Lagrangian

I am trying to implement a simple extension of the SM to Feynrules, generating the Lagrangian in a Mathematica notebook file. I am wondering about the following: Is there a way to explicitly use the ...
2
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0answers
42 views

HypExp and HPL packages for hypergeometric functions: Evaluating a function HPL[{minus,plus},x]?

I am currently using the HypExp and HPL packages, which are useful for expanding hypergeometric functions in series around integer or half-integer values, as in common in dimensional regularization ...
2
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0answers
267 views

Wormhole embedding diagram

I am trying to reproduce the embedding diagrams for the evolution of a Schwarzschild wormhole described in this paper. Following the paper notation, we denote the Kruskal coordinates by $(v,u)$. For ...
2
votes
0answers
595 views

Plotting the Magnetic Field

I have a dataset of $ \textbf{B} = {B_x, B_y, B_z}$. (Quite a big dataset :78*100*150) I want to plot magnetic field lines. If I was working with an analytical function, the magnetic field line ...
2
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0answers
344 views

Linear tangent steering law and orbital insertion altitude

I've been trying to figure out how to build a rocket launch simulation that allows the user to specify the desired altitude at which a payload will be inserted into a stable circular orbit, but have ...
2
votes
0answers
185 views

Modelling heat exchange between flowing fluid and surroundings

Starting from this question: Couple a PDE and ODE in NDSolve I would like to modify the fluid from static to a flowing one in the y direction. that's the original code that I modified a little bit: ...
2
votes
0answers
155 views

What is a good way to model fluid stream contours around airfoils?

I am an undergraduate student and am doing a project on conformal mapping for my complex analysis class. I have had one heck of a time trying to plot stream function contours to model fluid flow in ...
2
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0answers
102 views

How to implement time dependence in the DoFun package?

DoFun is a very usefull mathematica package that helps to write Dyson-Schwinger and FRG flow equations when these are to complex to write down by hand. You can download it here and read it's manual ...
2
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0answers
206 views

Numerical integration: complicated 2D integral seems to be poorly estimated

In the course of some physics research I've been working on, a very annoying integral has appeared that I'm having difficulty evaluating numerically. Any help you could offer would be greatly ...
2
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0answers
199 views

Creating an orrery

I am interested in creating an orrery, ideally with SystemModeler. I have been experimenting with the MultiBody library since that allows you to do animations. The most relevant example seems to be ...
1
vote
0answers
55 views

Trying to compute the heat capacity for the 2D-Ising model

I'm trying compute the heat capacity $C_v$ out of my simulation for the 2D-Ising model which is given by $C_v = \frac{\langle E^2 \rangle - \langle E \rangle^2}{T^2N^2}$ ($E$: Energy, $T$: ...
1
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0answers
45 views

Abstract derivatives in Feyncalc

I have encountered several problems regarding the application of formal derivative operators in FeynCalc, using the built-in function FCPartialD, Left/RightPartialD Schematic description of my ...
1
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0answers
53 views

Integrating wavefunctions over a sphere

I am attempting to numerically solve the inner product of two particles and an electric dipole interaction potential. I am incredibly limited in my skills, and need to know how I can begin setting the ...
1
vote
0answers
55 views

Decay chain browser

This https://demonstrations.wolfram.com/IsotopeBrowser/ used to be an excellent tool to demonstrate decay chains to my students. Unfortunately it does not work under newer versions of mma. Can anybody ...
1
vote
0answers
81 views

Animating a 3D plot of electromagnetic waves

Could an expert on this site guide me in making an animated 3D plot of electromagnetic waves? I would like the user to be able to change the polarization interactively. Also, I would like to run ...
1
vote
0answers
82 views

Problem with Wick Contraction

I'm trying to compute wick contractions knowing that: $\langle a_a a_b \rangle = \delta_{ab}$. So far I've the following ...
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0answers
71 views

NDEigensystem works for 3-D Schrodinger Equation but not 4-D

NDEigensystem works fine for the following 3-D Schrodinger Equation code -- Clear["Global`*"] Rcube = ImplicitRegion[-1 <= x <= 1 && -1 <= y <= 1 && -1 <= z <= 1, {x,...
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0answers
35 views
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0answers
104 views

Conformal field theory using Mathematica

Can someone suggest some open source mathematica packages to perform computations in conformal field theories e.g, OPE expansion, finding conformal blocks etc.
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0answers
81 views

Evaluate the electrical resistance between any two points of a circuit

I have an electric circuit of which the structure is known but the value of the single components (all resistors) is not. I can measure experimentally the resistance between some points of my circuit. ...
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0answers
89 views

Fisher Forecasting Using Mathematica

I'm need to do a Fisher Forecast for my experimental physics requirements. I'm trying to constrain parameter for a modified Friedmann equation. Is there any package or code that any of you have handy ...
1
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0answers
50 views

How to get a conversion factor in new system of unit

There is some numerical relation $I = \frac{c}{8\pi} E^2$ between the wave intensity $I$ and the electric field strength $E$ written in CGS (centimetre, gram, second) system of units, where $c$ is ...
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0answers
52 views

How do I get the output of a square-wave input? (singularity problem)

I am trying to get the electrical response of a system to an input square wave. Here is the code: ...
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0answers
100 views

Simpler way to compute gravity?

I have code for a simple n-body problem: ...
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0answers
218 views

Solving the 2D heat eqn with a rastering q term

I'm brand new to Mathematica so please forgive my lack of knowledge, I'm trying to learn it for my current internship! I'll try give some background to what I'm doing and where I could do with some ...
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0answers
262 views

Slater Koster parameters generated using Mathematica

Here is a link where people describe how one can generate the entries of the Slater Koster parameter table seen here as Table of interatomic matrix elements. The ...
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0answers
210 views

Solving 4 coupled differential equation for modelling boson star

I'm trying to study about modelling star from a journal. To get the characteristics of the star, I have to solve 4 differential equations which are coupled each other. I want to use Mathematica 9 to ...
1
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0answers
220 views

Tracking solutions over a Brillouin zone

Thanks to @bbgodfrey I have a function that finds the two solutions to a set of equations bounded by a hexagonal region (corresponding to the Brillouin zone). It takes the angle ...
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0answers
95 views

Help wanted in evaluating an integral

Trying to evaluate an integral. To be specific, I'm trying to find the expectation value of $x^2$ for the ground state of hydrogen. Here is the code I used: ...
0
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0answers
56 views

Calculating forces on a truss

I need to find certain forces of the truss shown above, and I am asked to calculate the forces with a matrix. The given values are ...
0
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0answers
77 views

Numerical integration: gravitational force

What I would like to accomplish is to numerically integrate the following equation: $\nabla^{2}\Phi(r)=\rho(r)$, to get $\nabla\Phi(r)$. $r$ is the radial distance from the origin. Suppressing the $...
0
votes
0answers
56 views

Heat conduction problem with boundary at $\infty$

This is a 1-D heat conduction problem for a circular rod with 5cm, $T(x,0)=0$, $T(\infty, t)=0$, left boundary is insulated. I am trying to use the finite numerical method. My first question is how ...
0
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0answers
22 views

FeynCalc example — muon decay — integration issue

I'm just starting out using Mathematica and I'm trying to work through one of the examples given for FeynCalc, specifically the muon decay: https://github.com/FeynCalc/feyncalc/blob/master/FeynCalc/...
0
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0answers
32 views

How to simplify my integrand to make the function Integrate[] work?

To calculate a physical field, I need to integrate a complicated expression, with Sin and Cos and some 3/2 power. But when I run the Integrate function, it seems running forever. So what could I do to ...
0
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0answers
46 views

Solve nonlinear differential equation system - Plot

When I solve the system of differential equations I get two solutions for each variable (See the picture). My question is how I can neglect one of the solutions at the plot. Thanks. Code: ...
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0answers
47 views

Graphene layer rotation

I made single layer graphene by using Code as below: ...