Questions tagged [physics]
Questions related to the application of Mathematica to problems in physics.
498
questions
3
votes
2answers
63 views
Plotting the derivative of NDSolve divided by the solution
I'm trying to solve the Friedmann equation as is given by:
$$
H^{2}=\Big(\frac{\dot{a}}{a}\Big)^{2}=H_{0}^{2}\big(\Omega_{m,0}a^{-3}+\Omega_{r,0}a^{-4}+\Omega_{\Lambda,0}a^{2.3}+\Omega_{k}a^{-2}\big),...
0
votes
0answers
49 views
Eigenvectors of Hermitian matrices [duplicate]
I asked a similar question in the physics stack exchange, but realized my question is probably more suited here.
For any Hermitian matrix $H = H^{\dagger}$ we can write $H = P DP^{\dagger}$ where $P$ ...
0
votes
1answer
59 views
Fitting nonlinear function does not converge but looks close to best fit
I'm having trouble fitting this transition temperature equation to my data. Physically speaking, the intensity should flatten out for T>Tc, which seems to be the biggest problem here. The equation I'...
0
votes
0answers
75 views
Free energy surface plotting
Please feel free to move this to a different board if it doesn't fit the best here.
I am working on trying to plot the free energy surface of ferroelectric materials, similar to the image below. Each ...
0
votes
1answer
72 views
Where can I find the package RGTC?
I am unable to find the package RGTC which is the prerequisite for the package Surface Charges that I require. All places I searched for only provide one download link which gives Error 404. Can I ...
0
votes
1answer
79 views
Modelling a cylinder [closed]
I am fairly new to Mathematica.
I am trying to model an ideal cylinder of uniform density of radius R (any arbitrary value) which has a cylinder of radius R/2 missing from it. The resulting solid is ...
1
vote
0answers
40 views
Fitting a Curie-Weiss law function with a diverging point to a data
I would like to fit a function to some experimental data such that the extracted value of Curie temperature (Tc) describes the temperature at which the response flattens out to a constant value. ...
0
votes
0answers
70 views
How to plot and simulate reaction networks in Mathematica?
I am trying to simulate reaction networks like it's done in the Simulation methods
in this paper. They used Xcellerator, so I after installing on Mathmatica 11.2 and trying to run their Belousov-...
0
votes
1answer
53 views
Magnetic field for certain distance
I have a question in theoretical physics. I have a magnetic field created by conductor loop
bz = (\[Micro] i )*8/(5 Sqrt[5] R);
with distance D = 2b and would ...
1
vote
1answer
47 views
Iterative solution for particle in magnetic field
I have some questions relating movement of a particle calculating with mathematica.
A particle (mass: m, charge: q) moves on x-axis from left with speed $v_0$ to a magnetic field $\vec{B} = (0,0,B)$. ...
15
votes
2answers
2k views
Turing patterns
I am new in learning Turing patterns. Is there any sample code available to generate such patterns in ecology model (Lotka–Volterra model)?
The above figure is taken from this paper, and is based on ...
1
vote
1answer
52 views
Color scheme problem
I have a problem in the color scheme in a 2D spectra.
After a lot of calculations, i can generate a picture like this
in the last part using this instructions
...
6
votes
3answers
503 views
How to set interface conditions for optical waveguide in NDEigensystem?
I have been working on waveguide mode analysis using FEM in Mathematica for a week, but I haven't succeeded until now.
The optical fiber-like waveguide is featured with different refractive index in ...
0
votes
0answers
31 views
Can't get TensoriaCalc to work
So I'm trying to use TensoriaCalc, and it won't work. I put it this
...
5
votes
1answer
61 views
How to change the default normalization for NDEigensystem?
I'm currently using NDEigensystem to solve a PDE that describes a particle travelling on a hyperbolic (negatively curved) surface. However, the eigenfunctions that are returned by NDEigensystem are ...
4
votes
0answers
64 views
Improving NetChain for Physical Data
I am trying to improve my NetChain to better predict physical data from the industrial standard for water/steam published by the IAPWS.
Basically, this industrial ...
1
vote
1answer
153 views
Electric Field Plot
I want to show an electric field of several arrangements of point charges in xy-plane.
I wrote a routine that plots an electric field of a charge:
...
6
votes
0answers
243 views
Butter side up?
I've written a piece of code that determines if a piece toast with butter lands on the butter-side or not, depending on its initial velocity and the table height. If you are interested in the physics ...
0
votes
0answers
29 views
Opacity or related issue with DensityPlot3D
I'm trying to make use of the function DensityPlot3D with the following specific example
...
0
votes
0answers
38 views
Manipulate plot of a system of PDEs with NDSolve
Modeling 1D diffusion of an enzyme, e, through a sphere with substrate, s, I arrive at the below equations:
I then pass these equations to NDSolve, Evaluate at a range of r and t and Plot and ...
0
votes
0answers
16 views
How can I know the true range of the values returned by AudioLocalMeasurements?
I need to normalize the values of different AudioLocalMeasurements results but I can't seem to find any info regarding the range of values in which each measurement ...
3
votes
1answer
63 views
Evaluating Hough functions by using NDEigensystem on the Laplace tidal equation
Currently I am looking into the use of Mathematica to solve the classical tidal equation of M. Laplace:
$$\mathcal{F}\Theta+\gamma\Theta=0$$
whose eigenfunctions $\Theta$ are the Hough functions. ...
1
vote
1answer
60 views
How can I animate two beads each sliding on its own frictionless rail? [closed]
I am told to animate two beads sliding on rails in Mathematica, but I am very confused on how to get a mass on a rail and it move up and down the rail.
3
votes
1answer
273 views
3D rigid body physics engine
Is there a package in Mathematica that will allow me to simulate collisions of 3d rigid bodies?
If not, what known libraries could I use and how?
For example, one problem I want to simulate is a ...
0
votes
0answers
51 views
How to solve a Poisson's differential equation with a boundary condition at infinity?
Context: This question is relevant to the physical problem of calculating potential for a set of p-n-p junctions.
We have to solve a Poisson's differential equation for a p-n-p junction with ...
0
votes
0answers
68 views
Clebsch Gordan coefficients
I'm trying to compute various sums which contain some CG coefficients, where the sum runs over the indexes m1,m2,m corresponding to each of the three angular momenta j1,j2,j. The thing is that when I ...
9
votes
0answers
206 views
Solving the 2D Schrödinger equation with eigensystem, then verifying orthonormality of eigenfunctions with NIntegrate
I am solving the time-independent 2D Schrödinger equation for an interacting electron and hole in the case of anisotropic electron and hole masses, where the interaction is described a modified form ...
0
votes
1answer
93 views
How to construct — based on physics-type notation — a magical simplex $\mathcal{W}$ of bipartite qutrits?
I have a short Mathematica program:
...
4
votes
1answer
133 views
Currents/voltages graph for an electrical circuit
I am trying to design the network graph for an electrical circuit. I have done this by hand so far. Here is the code for the voltages graph
...
4
votes
1answer
163 views
3
votes
0answers
127 views
Physics based predictive model using Predict
Summary:
The first order response of a block of metal quenching in a fluid (or a cold block heating in a warm environment) is well known. I am trying to create a physics based predictive model for ...
0
votes
0answers
86 views
How can I define another metric (disformal transformation) in xAct?
I'm using the xAct package. I want to define two metrics with the disformal transformation relation
$\qquad \bar{g}_{\mu\nu}=A(\phi) g_{\mu\nu}+B(\phi)\nabla_\mu \phi\nabla_\mu \phi ,$
where $g_{\...
1
vote
0answers
54 views
0
votes
1answer
132 views
Plotting elliptical orbits using Verlet method
I'm looking to solve a 2 body system consisting of the Earth and a body of mass in orbit.
I'm using the Verlet method to numerically integrate Newton's equation of motion in order to plot an ...
2
votes
2answers
73 views
Finding the amplitude of function solved using ParametricNDSolve
I have been trying to find the peaks of a function I have plotted using ParametricNDSolve. I have to find these peaks to calculate the amplitude of all the various waves in the observed output. By ...
1
vote
1answer
97 views
Conditional evaluation: black hole cross section
I'm trying to calculate the collision cross section of black holes, more precisely, I want the critical impact parameter $b_{\text{crit}}$ for a given initial velocity $v$ such that, at this speed, ...
28
votes
2answers
1k views
Animating wave motion in water
Further to this question I found on MSE, I tried to replicate
from here
this is as far as I got:
...
12
votes
2answers
802 views
Solving “Resistance between two nodes on a grid” problem in Mathematica
In the context of resistor networks and finding the (equivalent) resistance between two arbitrary nodes, I am trying to learn how to write
a generic approach in Mathematica, generic as in an approach ...
1
vote
1answer
74 views
Solve Euler Lagrange equation of motion DSolve
I'm trying to find Euler Lagrange equation of motion.
then DSolve the equation for list of variable x1,x2,x3,x4
Here is my code:
...
-1
votes
1answer
162 views
Working with motion equations
I'm trying to solve some Lagrange differential equations of motion, where $L = T - U$. Also, how can I use the solution for each x1, x2, x3, ..., xn?
Here is my code:
...
2
votes
0answers
49 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 ...
0
votes
0answers
62 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
...
1
vote
1answer
83 views
A program for finding the summation of an analytical expression
Consider the Baker-Hausdorff formula for two operators $A$ and $B$:
$$e^BA e^{-B} =A+[B,A]+\frac{1}{2!}[B,[B,A]]+\frac{1}{3!}[B,[B,[B,A]]]+....,$$
where $[A,B]=AB-BA$. In the case of my problem, $[B,...
0
votes
1answer
109 views
Creating a numerical table of values from an interpolating function resulting from NDSolve [closed]
I am trying to carry out point "Implementing Map" on this paper Interstellar wormholes however I am using my own equations not those given (only the same method).
Part 1
I am trying to create a ...
0
votes
1answer
70 views
Using ParametricNDSolve with n subscripted functions
I want to calculate trajectories of an n-pendulum. For the number n=1 it's just a pendulum, for n=2 a double pendulum , for n=3 a triple and so on.
The Solver has to solve n equations for the angle. ...
0
votes
0answers
87 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
67 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 ...
2
votes
0answers
83 views
Using Image Transformation to create image sky view of what its like to be near black hole (Not a wormhole) [duplicate]
Question : I am trying to carry out point 3. "Implementing map" on page 13 in the paper Interstellar wormholes using my own equations not those in the paper. however am not 100% sure on how to go ...
2
votes
1answer
69 views
How do I draw an angular vector field containing a domain wall?
Intuitively, an angular vector field $\theta(x)$ such as the following would describe a domain wall between two vortices/strings of opposite winding number.
I would like to draw this on a computer ...
3
votes
2answers
135 views
Carnot cycle diagram
Note: I have adopted and modified code taken from Wolfram demonstration page.
I want to achieve something similar to the following figure:
I use the following code:
...
