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

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4
votes
1answer
177 views

Recognize physical constants?

Is there some way to ask Mathematica to recognize physical constants, such as 32 or 9.81 (gravitational acceleration, in different units, at Earth's surface)? I have in mind something like the "...
3
votes
1answer
153 views

Controlling scaling of multiple vector fields in VectorPlot3D

I'm trying to plot the electric and magnetic fields of a relativistically moving electric charge using VectorPlot3D, and apply "Manipulate" to change the velocity. The code I'm using is as follows: <...
10
votes
0answers
173 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....
6
votes
0answers
237 views

Problems with NDSolve for solving coupled Schrödinger-like PDEs with perfectly matched layer boundary condition

I'm trying to solve a full-vectorial wave equation for an arbitrarily shaped wave guide, by using NDSolve and perfectly matched layer (PML) conditions. The PML ...
3
votes
0answers
197 views

How to solve the Tsunami model and animate the shallow water wave?

Recently when I was learning differential equations, I noticed there is a shallow water wave equation to model the tsunami propagation. How to establish and solve the initial and boundary conditions ...
3
votes
0answers
170 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 ...
3
votes
0answers
150 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, ...
2
votes
0answers
104 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
votes
0answers
143 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 ...
2
votes
0answers
443 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
votes
0answers
407 views

Crank-Nicolson scheme for the Schrödinger equation

I am trying to solve the 1-D Schrödinger equation with the Crank-Nicholson method. I use the atomic units: time < 10^-14 => 413 a.u.t. length 30 * 10^-9 m => 567 Bohr radii ...
2
votes
0answers
149 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\...
1
vote
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 ...
1
vote
0answers
111 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
vote
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
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 ...
1
vote
0answers
63 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 ...
1
vote
0answers
91 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
votes
0answers
91 views
0
votes
0answers
91 views

Animating ballistic movement

I was tasked with creating a 3D animation of the movement of a ball through space, while taking into account influences such as the magnus effect, air drag, and rotation. In order for this to happen a ...
0
votes
0answers
51 views

Eigenelements of conductivity equation

I am trying to calculate the eigenvalues and eigenfunctions of the conductivity equation in an annulus. In particular I am looking for $(\lambda, u)$ s.t. $$ \begin{cases} \Delta u = \lambda u & \...
0
votes
0answers
34 views

Solving Time-Dependent PDE's Analytically with no non-trivial Boundary Conditions

I'm having some trouble solving a partial differential equation that is supposed to model the propagation of a scalar field in Schwarzschild spacetime using spherical coordinates. I'm using the DSolve ...
0
votes
0answers
38 views

Recycle boundary condition

I'm having the following issue that can not find a solution , by using this boundary condition u[0, t] == 2 u[1, t] that Mathematica does not understand, someone ...
0
votes
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
votes
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 ...
0
votes
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 ...
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 \...
0
votes
0answers
191 views

FeynRules issue when trying to export UFO file

I am having problems with the UFO file generated by a very simple model using FeynRules. The following error occurs when MadGraph tries to import the "Model_UFO" file: ...
0
votes
0answers
500 views

How to obtain differential equations of motion using Lagrangian dynamics?

I'm confused to find a set of differential equations of motion of a pair of masses, m1 and m2 joined by a spring of constant <...