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

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1
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1answer
53 views

Need help with “Filling” in a plot, generated with a table. (Wavefunctions)

I'm trying to get a result like this: ...
2
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1answer
145 views

Solve 2D diffusion equation in polar coordinates

I am trying to solve the diffusion equation in polar coordinates: $\frac{\partial u}{\partial t} = D \left( \frac{\partial^2 u}{\partial r^2} + \frac{1}{r} \frac{\partial u}{\partial r}\right)$ ...
0
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0answers
139 views

Three Body Problem Equilateral Triangle

I'm currently working on showing that the equilateral triangle arrangement of the three-body problem has an analytic solution. So far I've written the equations of motion of each body into Mathematica ...
0
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0answers
41 views

How to combine two matrices.? [duplicate]

let A, B are any 4 by 2 Matrices , i want to know whether it is possible to obtain a 4 by 4 matrix by using equation A=B Thanks in advance
1
vote
1answer
184 views

Polarization sum in FeynCalc

I think I know how to sum over final state fermion spins (FermionSpinSum[...]?) but what is the analog expression (in FeynCalc) if you have two or more polarization ...
1
vote
1answer
338 views

Calculating the normalization constant for a wavefunction

How can I compute the normalization constant for a quantum mechanics wave-function, like $\Psi(x) = N \exp(-\lambda x^2/2)$ by using Mathematica? (The normalization constant is $N$).
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0answers
63 views

How to combine similar terms in a density matrix expression? [Ref: Quantum Computing]

I tried the following : Simplify, FullSimplify, and Expand. Due to this problem, I am not ...
1
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1answer
99 views

Divergence of $1/r^2$: Mathematica yields 0, while the correct answer is a DiracDelta

In spherical coordinates, the divergence of a point charge is $4 \pi \delta (r)$, the three-dimensional Dirac delta function. In ...
2
votes
2answers
306 views

Help with NonLinearModelFit

I have a question about fitting data with a model. I have a quite complicated model, based on Arctans, modified Bessel functions, etc, that I want to fit to my data, a table of couples (minimal ...
2
votes
2answers
235 views

Attempting to use NDSolve to plot harmonic oscillator solutions

NDSolve[{ (-y''[r]/1880) + (470 (0.04077)^2 r^2 - 48 + 1/(1880 r^2)) y[r] == 0, y[0] = 0, y'[0] = 0}, y, {r, -4, 4}] I use this but get errors and am ...
2
votes
1answer
96 views

Singularity while solving PDE

I have to solve a PDE (in the context of the functional renormalization group in physics). I have a function of two variables, $U(l,p)$. I know $U(0,p)=U_0(p)$ and then I have an equation (eq925) that ...
5
votes
1answer
129 views

A 1D numerical integral Mathematica cannot compute, from physics

A well know result in theoretical physics is that a sum over Matsubara fermionic frequencies, i.e.: $$ S = \sum_{n=-\infty}^{\infty} h(\omega_n) \hspace{32pt} \omega_n=(2n+1)\frac{\pi}{\beta} $$ can ...
7
votes
2answers
410 views

Plotting 2-D Electron Density Carbon Atoms

I need to create a 2-D electron energy density plot in Mathematica to compare with my STM experimental results in my lab class. This would be done by plotting the sum of the symmetric and anti-...
8
votes
2answers
323 views

Boson commutation relations

I have tried to adapt this answer to my problem of calculating some bosonic commutation relations, but there are still some issues. The way I'm implementing the commutator is straightforward: ...
1
vote
1answer
366 views

How can I use Mathematica to solve a Stefan Problem using an explicit scheme?

I would like to plot the temperature distribution for a particular case. the problem is stated in the paper, behind a paywall here, summarized as Consider a one-dimensional container of length l, ...
3
votes
1answer
111 views

How to reduce an expression into user-defined variables?

In the following code, I define a set of matrices. Then, I define a function that calculates the commutation relation relation between these matrices ...
6
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2answers
395 views

Time evolution/dynamics of circular plate with hole (Biharmonic equation and stiffness)

On this Mathematica.SE form, there exists information on how to use Mathematica to demonstrate the vibration of a circular membrane and the deflection of an orifice plate (the latter I had raised ...
1
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0answers
391 views

Time evolution of a bispinor [duplicate]

The effective Hamiltonian for polariton graphene is given by: ...
7
votes
0answers
174 views

Interfacing Red Pitaya board with Mathematica [closed]

I just discovered the Red Pitaya board and borrowed a unit to play during this weekend. Surprisingly I did not find any reference to Mathematica on the Red Pitaya forum, nor did I find any reference ...
4
votes
1answer
147 views

Help nedeed for understanding NDSolve architecture -Vacuum Heating Simulation

I am a beginner in mathematica and I am facing a problem that is way bigger than my knowledge.. I am tryng to simulate a semplificated version of Brunel Effect, wich is a Laser-Plasma interaction ...
2
votes
1answer
147 views

Equal flow boundary conditions

I'm having the following issue that can not find a solution , by using this boundary condition v[0, t] == u[1, t] that Mathematica does not understand, someone ...
1
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0answers
111 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 ...
7
votes
3answers
392 views

FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions

I found the deflection of an orifice plate (circular plate with a hole) subject to uniform pressure using Mathematica's NDSolve functionality. The plate is fixed at its outer circumference and is ...
2
votes
1answer
317 views

Potential flow over cylinder with FEM: Pressure field is flipped

Much in the fashion of a few problems already answered on Mathematica.SE (1, 2), I am trying to solve the Laplace equation in velocity potential $\phi$ to simulate irrotational, inviscid flow over a ...
1
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0answers
101 views

How to obtain the magnetic field of the following set up [closed]

This is the experimental set up: A ferromagnetic cylindrical disk (of irrelevant dimensions) has either sides set at different electric potentials (left side at 0 volts and right side at 1 volt). A ...
1
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0answers
151 views

Alternatives to Mathematica that are not computer algebra systems [closed]

Are there alternatives to Mathematica that are not computer algebra systems? I know there have been questions on this, but I am focusing on oprn source projects and instead of focusing on computer ...
1
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0answers
110 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 ...
0
votes
1answer
84 views

Find all degenerate eigenvalues of a cubic equation

I have an equation that is cubic in w. The three solutions correspond to bands in a bandstructure, and are a function of wavevector ...
4
votes
1answer
205 views

Specifying NeumannValue for Axial load instead of transverse load (Plane Stress situation)

I am trying to simulate a bar/link element under axial tensile load. The link is of unit thickness and I may use a plane stress model. A plane stress model is an approximation that may be used for ...
5
votes
3answers
245 views

Finding the conditions for degenerate solutions to a cubic equation

I have a cubic equation (corresponding to the band structure of a physical system) given by w in the code below. ...
3
votes
1answer
88 views

Eigenvalues function not producing expected results?

I'm running into a strange issue when trying to compute eigenvalues of a 2x2 matrix for graphene. If I "manually diagonalise" by multiplying the two off-diagonal terms together and taking the square ...
0
votes
1answer
97 views

FullSimplify not giving me a physically useful answer for Mott scattering

I am using Mathematica to find the cross-section for Mott scattering over an extended target. I evaluated ...
1
vote
1answer
205 views

Modeling a stellar atmosphere

I'm trying to model a stellar atmosphere using Mathematica. Basically I'm working in a physical and chemical model which combined should give me a profile of the chemical abundance in the atmosphere. ...
22
votes
3answers
1k views

How to plot an emission spectrum?

If I have a list of data with various wavelengths in nanometers, how would I plot them on a graph so it looks like this: So far I have managed to plot a spectrum in ...
1
vote
1answer
284 views

Van der Waals Isotherms [closed]

I have the following code: ...
2
votes
2answers
275 views

Solving coupled first-order autonomous differential equations

I am trying to run a simulation of a circuit to observe chaotic behavior, and have obtained a set of differential equations from an analysis of the circuit. I thought perhaps I could produce a plot ...
14
votes
3answers
336 views

Mimic a procedural, recursive clustering algorithm for site percolation using functional programming

Sorry in advance for my logorrhea: I just want to make sure all of the information is here. Context and Question I am investigating site percolation on a square lattice. I have a working, depth-...
0
votes
1answer
129 views

Animating a parametric plot

I am attempting to animate my parametric plot, but am having difficulties. I tried simply wrapping the plot code with an Animate[expression,{t,0,5}], but that hasn'...
8
votes
2answers
938 views

Defining quantum-mechanical Bra and Ket operations

I have the following ket in the Fock basis: $\vert3, 0 ,1\rangle$, where each entry defines the number of photons in a particular mode and can take any one of the following numbers: 0, 1, 2, 3. As a ...
7
votes
1answer
282 views

Synchrotron Radiation and ListDensityPlot

I'm trying to reproduce the following plots: As described by this blog entry: Synchrotron radiation As you can see in the linked article, the task is essentially to make a ...
1
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0answers
156 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 ...
1
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1answer
86 views

Diff eqs can be solved?

I'm trying to solve a pair of coupled differential equations, but am having trouble making DSolve evaluate my equations. ...
1
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2answers
142 views

Plot ParametricNDSolve

I am trying to plot the probability of a molecule being in a certain state via the numerical solution of the Schrödinger's equation of molecule in an oscillating electric field (in a rotating system). ...
3
votes
1answer
133 views

Fundamental question about capabilities of Mathematica to represent abstract mathematics [closed]

I have an fundamental question about what Mathematica can and cannot do. I have a book which presents a certain physical theory in an axiomatic manner. The axioms make heavy use of mathematics. Some ...
0
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0answers
40 views

How to solve coupled first-order ODE with vectors?

m * v'[t] = q * (E + v x B) using the following: B = (0,0,B0), E=(Eperp,0,Ez). How would I find the general solution of ...
1
vote
0answers
91 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 ...
0
votes
0answers
84 views

Difficulty solving an equation involving a couple of different powers

I have this semi-complicated equation to which I want to find an analytical solution for $\epsilon$. The equation is a s following: $$a^2 (2 b k \epsilon \sqrt{1 - \epsilon^2/b^2} - 2 c k \...
8
votes
1answer
373 views

Diverging solution to coupled second order ODEs from NDSolve

For a physics application I am considering the radial Bogoliubov-de Gennes equations in two dimensions. In dimensionless form they read as follows $$ \begin{cases} \bigg[\frac{1/4-m^2}{r^2}+2(E-1)\...
7
votes
2answers
560 views

Integrating a function over a surface integral

From a first principles bandstructure calculation I get an energy scalar field in three dimensions $E(x,y,z)$. It's now easy to plot a constant energy (contour)-surface for dedicated values $\epsilon=...