# Questions tagged [physics]

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

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### 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 ...
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 ...
44 views

### Plot in mathematica about a particular point

I am new at mathematica. I have a differential equation ...
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 ...
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 ...
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
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 ...
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### 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 ...
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 ...
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### 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 ...
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, $a$ ...
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 ...
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 [...
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)....
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 ...
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 ...
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 ...
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 ...
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 ...
172 views

### 2 body orbits around a barycenter

I'm attempting to plot a barycentric orbit of the sun and Jupiter. Initial Conditions ...
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 ...
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 ...
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 ...
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### 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 ...
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 ...
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: ...
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 ...
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### 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: <...
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### 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 ...
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 ...
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 ...
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 ...
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 ...
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),...
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### 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 $P$ ...
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'...
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 ...