Questions tagged [physics]
Questions related to the application of Mathematica to problems in physics.
540
questions
2
votes
1answer
32 views
How do I make exponential graph show only one trend-line with two lists of data?
Below is my code containing two lists of data, I need the graph to show one exponential trendline from an exponential equation, but it currently shows one trendline per item in the list. I am sure ...
0
votes
0answers
34 views
2+2 decomposition in xAct
I'm working on perturbation theory around a black hole and I want to decompose my perturbation tensor on the 2-sphere, but I don not need to work in a specific basis. I would like to know how to ...
1
vote
0answers
44 views
Plot in mathematica about a particular point
I am new at mathematica.
I have a differential equation
...
1
vote
0answers
46 views
Electric field vector plot [closed]
Be able to input (x,y) and Coulombs of point on plane and generate electric field plot.
Also be able to add as many points as possible.
Thanks
This is what I want, but not random points:
Electric ...
10
votes
3answers
563 views
Finding orbits in the Schwarzschild spacetime
I am trying to plot Schwarzschild's orbit without invoking the geodesic equation.
As a reference I am using Chandrasekhar's Book (The Mathematical structure of Black Hole, OUP). In page 98 of the ...
0
votes
1answer
30 views
How do you take imported data and and break the data into two lists, one even numbers and one odd numbers [closed]
Trying to use the simpsons rule to look at work done for a dragged chain
0
votes
0answers
46 views
How to set correct initial conditions while solving a Differential Equations set?
I tried to solve a physical problem (IYPT No.7 Balls on a String) by referring to the example/DoublePendulum in the help document. However, an error was reported when the program running. Where are ...
2
votes
0answers
178 views
How to fit my data with following equation?
I have set of data of electronic specific heat ($C_{el}/\gamma_n T$) vs temperature ($T/T_c$). My fit equation is this
$$\frac{C_{el}}{\gamma_n T}=-\frac{6}{\pi ^2}\alpha \frac{\mathrm{d} }{\mathrm{...
0
votes
0answers
55 views
Calculating with deformed Heat equation?
How can I implement the following equation and start computing numerically?
The first partial derivative can take fractional numbers.
4
votes
1answer
151 views
How to determine the direction angle of a point relative to the principal direction in the three-dimensional Mohr's circle
The three-dimensional stress state of a point in the solid after rotation is as follows:
...
4
votes
1answer
131 views
Implement Baker-Campbell-Hausdorff expansion
I wish to calculate the recursive formula,
$$\mathrm{e}^{-A_1 \Delta t/2}\mathrm{e}^{-A_0 \Delta t/2}B\mathrm{e}^{A_0 \Delta t/2}\mathrm{e}^{A_1 \Delta t/2} $$
with the BCH expansion to second order ...
2
votes
0answers
31 views
Contraction of tensors in chart (xCoba)
I have to do some calculations on modified gravity in xAct. The question is how to construct tensors, made of other tensors with contraction in particular chart. Without chart it can be done with <...
1
vote
0answers
38 views
Obtain the vector potential and magnetic vector of infinite wire carrying charge
I'm working on the question above, but I'm really stuck for days. my goal is to implement the following Problem in Mathematica. Any help would be appreciated.
I want to evaluate the following ...
0
votes
0answers
57 views
Ground state Of Gross Pitaevskii Equation
I want to plot the ground state of Gross-Pitaevskii equation using NDSolve. I am using the following code:
...
1
vote
0answers
35 views
Scattering propagating wave on potential using Manipulate and ListPlot
I have written the following code:
...
0
votes
0answers
27 views
Inconsistency in complex line integral using 2 parameters vs 1 parameter
I am trying to numerically verify that, over a closed circular path,
the line integral of a physics-inspired complex quantity $z_Q = P \cdot \frac{\partial}{\partial Q} S$ is
the same regardless of ...
2
votes
0answers
101 views
Model 1D Vlasov Equation
Vlasov Equation
The non-relativistic form of the Vlasov equation is given by:
$$
\partial_{t} f\left( \mathbf{x}, \mathbf{v}, t \right) + \mathbf{v} \cdot \nabla f\left( \mathbf{x}, \mathbf{v}, t \...
4
votes
1answer
481 views
Merging two 2D wave animations into one 3D animation?
I have an electric field,
Elec[d_, w_, q_, r_, t_] = -((q accel)/(4 \[Pi] Subscript[\[Epsilon], 0] r c^2))
Subscript[\[Epsilon], 0] := 8.85*10^-12
c := 3*10^8
...
1
vote
0answers
51 views
Having issues trying to animate an electric and magnetic field of a moving point charge [duplicate]
I'm currently trying to plot an electric and magnetic field using Mathematica, but I'm quite new to the program and I've run into a wall.
I start out with a moving point charge, and this is what I've ...
1
vote
1answer
96 views
1
vote
2answers
106 views
Plotting the electric field from a moving charge in 3D
I want to show a 3D electric field changing with time in response to the path of a moving charged particle. I have an animation of a particle traveling along a helical path using the parametrization ...
2
votes
1answer
170 views
Problem with numerical solution of a system of ODEs
Background
Good evening, I have a big problem with num. solution NDSolve of differential equation.
To start with, the model:
There is a fast-moving rope in closed path. Where
$T$ is tension,
$a$ ...
3
votes
1answer
125 views
Trying to understand Electromagnetism using mathematica
I was wondering if there was a possible way to animate electric and magnetic field lines using Mathematica?
I'm currently doing a physics major and taking an upper level electromagnetism course. I'm ...
0
votes
0answers
31 views
Error when using NDSolve Unable to find initian condition - beam bending
please I have the following problem: I have a set of equations for the elasto-plastic response. I have decomposed the beam into two segments (the first segment is defined by coordinates [x1,y1] and [...
1
vote
0answers
39 views
How to solve an Integral analytically using a predefined definition for Besselfunctions (phi part of angular spectrum representation)
I'd like to use mathematica to calculate an Integral that is dependent on phi and theta (to obtain the intensity distribution of a tightly focused TEM20 mode using the angular spectrum representation)....
3
votes
1answer
61 views
Getting a stable solution for a simple first-order PDE
I have what is in my estimation a pretty simple PDE. It's the Liouville equation for the density of points in phase space with a hyperbolic secant potential. But when I try to solve it with NDSolve, I ...
6
votes
3answers
239 views
Heat Flow in a Pipe
I try to model the transient heat flow in a pipe, assuming that the temperature in radial direction doesn't change:
temperature ...
2
votes
1answer
78 views
More elegant/efficient numerical WKB implementation for 1D Schrödinger Equation
I'm trying to figure out a better way to implement numerical WKB quantization of a spectrum. WKB quantization is the condition that
$$\oint_{E}p \, \mathrm{d}q = \pi \hbar (n+1/2)$$
So the idea to ...
3
votes
1answer
90 views
RegionCentroid and center of mass
If we have three masses $m_1,m_2,m_3$ (assuming that are all equal to $1$) located at $r_1,r_2,r_3$ respectively, then the center of mass is at $(1.00,0.83)$. In the Wolfram Documentation page says ...
7
votes
2answers
239 views
Solving a steady-state viscous Burger's equation with NDSolve
A steady-state viscous Burger's equation is given by
$$ u\,u'=\nu \,u'', \quad x\in (-1,1), $$
$$ u(-1)=1+\delta,\quad u(1)=-1.$$
Here $\nu>0$ is the viscosity, $\delta>0$ is a small ...
0
votes
1answer
172 views
2 body orbits around a barycenter
I'm attempting to plot a barycentric orbit of the sun and Jupiter.
Initial Conditions
...
2
votes
0answers
30 views
What kind of performance should I expect out of Eigensystem using FEAST?
I'm numerically solving a time-independent Schrödinger equation using Eigensystem's FEAST method. It takes a lot longer than I ...
3
votes
1answer
179 views
Electric field produced by a capacitor consisting of two parallel plates of different lengths
I need to visualize the electrostatic field produced by a capacitor consisting of two parallel 1D plates of different lengths, as shown in the following figure (sorry for the crude drawing), in which ...
4
votes
1answer
224 views
gravitational two body problem for the orbit of the sun and jupiter around their barycenter
This is a simulation of the sun and jupiter orbiting the respective barycenter.
Initial conditions
...
0
votes
1answer
89 views
Dynamical System
I'm Trying to solve dynamical system in friedmann universe. But, I have problems with initial conditions to $\Omega_{\Lambda}$ and $\Omega_{k}$. The code that i'm implementing is
...
10
votes
0answers
317 views
Solving Maxwell's Equations in Mathematica
For the sake of demonstration (for my students) and practice, I wanted to numerically calculate the electric and magnetic field (3D) for a sphere of uniform density moving slightly to the right and ...
0
votes
1answer
56 views
Remove +0Is from Root function
I'm trying to find the zeros of the eigenvalues (functions of $k_x$) of a self-adjoint $4\times4$ matrix H:
...
4
votes
2answers
168 views
Plotting perpendicular lines to a contour plot (electric field from equipotential curves)
I'm currently working on a experiment about Electric Fields and Equipotential Curves. The problem is that I want to plot (estimate) the curves of electric field using the fact that every one of these ...
4
votes
2answers
87 views
Possible error in IsotopeData
I found 2 isotopes in Wolfram database which are marked as unstable, but their lifetime is indicated as infinite (germanium-76 and selenium-82). The following chunck of code illustrates the issue:
<...
2
votes
0answers
66 views
NBodySimulation in ParallelTable [closed]
When I use the NBodySimulation in a ParallelTable I do not get multiple processors effectively activating. If I want to sweep ...
3
votes
1answer
293 views
Distinguish FeynRules, FeynCalc, FeynArts, FormCalc and LoopTools
I am totally confused: I can't distinguish the packages FeynRules, FeynCalc, FeynArts, FormCalc, LoopTools properly.
Once I installed FeynRules I think. It seems to include the packages FeynCalc and ...
6
votes
2answers
1k views
How to get Planck length in meters to 6 decimal places
I want Mathematica to format quantities to more decimal places than the default.
For example I have tried
...
1
vote
1answer
85 views
WhenEvent error in NDSolve ODEs
I wish to change the term, T'[t] to 0 when S[t]<=0 when I solve ODEs. I have used WhenEvent in my NDSolve part, but it seems not work. The code is
...
1
vote
0answers
81 views
Plot of Laguerre-Gaussian wavefront
I have tried to plot the wavefront of a Lagherre-Gaussian bean, I know that to do that i have to plot the set of all points where the wave has the same phase.
I have try to use the conditional If ...
3
votes
2answers
89 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
53 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
80 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'...
1
vote
0answers
105 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
270 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
82 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 ...
