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

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3
votes
1answer
131 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 ...
8
votes
0answers
119 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 ...
6
votes
0answers
125 views

Heat convection differential equations from 1952 - Mathematica “fails to converge”

I am trying to solve a fundamental problem in analytical convective heat transfer: laminar free convection flow and heat transfer from a flat plate parallel to the direction of the generating body ...
3
votes
0answers
162 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
145 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
129 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
402 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
347 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
133 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 ...
1
vote
0answers
75 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
92 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
136 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
60 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
57 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
88 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: ...
1
vote
0answers
184 views

Solving PDEs with complicated boundary conditions

The system I'm trying to solve is $$\nabla^2 C_{(r,\theta)} =0$$ $$C_{(\infty,\theta)}=C_0$$ $$ [ \frac{\partial C_{(r,\theta)}}{\partial r} \cos(\theta)+\frac{1}{r}\frac{\partial ...
1
vote
0answers
90 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
106 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
41 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
51 views

Plotting a parameterized vector in the x-y plane

I am trying to plot the trajectory of a parachutist descending at a constant vertical rate of 8 m/s while a south wind also blows at a rate of 8 m/s. He initially jumps from a height of 300 m. I am ...
0
votes
0answers
35 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
80 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
227 views

Plotting: Magnetic field lines

I have data which I am trying to plot as 3D field lines. I need to plot points at coordinates i, j and ...
0
votes
0answers
35 views

Can't Load .rst file

I've been working with the FeynRules 2.1 package in Mathematica 10. If I download the MC4BSM_2012 FeynRules files and run the Mathematica Notebook I've got no problem in Ubuntu (A lot of warnings ...
0
votes
0answers
164 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
378 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 ...