Mathematica Definition and 1000 Threads

Hi, I was wondering if someone could help me understand the grid command in the following Mathematica code that transforms a rectangle to a torus like in this video below. My problem is I want the blue rectangle in the Mathematica code to look like the four color rectangle in the plot below...

Suppose I have a differential equation $$\ddot \phi + 3H (1+Q) \dot \phi + V_{,\phi} = 0$$ where ##\phi## is the inflaton field. ##H## is the Hubble parameter, ##Q## is just a number, ##V_{,\phi}## is the derivative with respect to ##\phi##, and initial conditions given by ##\phi[0] = 2...

In cosmic inflation, we have the equation of motion for the inflaton given by, $$\ddot\phi + 3H(1 + Q)\dot\phi + V_\phi = 0$$ the Friedman equation is given by $$H^2 = \frac{1}{3 M_p^2}(\frac{1}{2} \dot\phi^2 + V + \rho_r)$$ where ##M_p## is the reduced Planck mass. The differential equation...

I am trying to learn RGTC. It gives value of particular Riemann tensor but not all of it. What should I do?

I have a very large expression: j - Sqrt[q^2 + qp^2 - 2 q qp Cos[\[Theta]]] - \[Sqrt](qp^2 + 1/2 (16 m5^2 + ma^2 + mp^2 - Sqrt[(-(16 m5^2) - ma^2 - mp^2)^2 - 4 (ma^2 mp^2 - 16 m5^2 qp^2)])) == 0 where \[Theta] = Pi/6; ma = 980; mp = 139; j...

I want to plot a function f(x) such that it's domain is from 1 to 10000 but I want the graph to read 1, 10, 100, 1000, 10000 in the x-axis, while the y-axis is normal. ##f(x) = 2\sin^{-1} ( e^{-\frac{60}{x}})##

I am solving the following system of equations (in matrix form): ##\begin{pmatrix} 1 & -2 & -1 & 1 \\ 2 & -3 & 1 & 6 \\ 3 & -5 & 0 & 7 \\ 1 & 0 & 5 & 9 \end{pmatrix}## I want to solve it using Mathematica, but when I use the command LinearSolve[], I only get back ##\begin{pmatrix} 9 \\ 4 \\ 0...

I have a simple Mathematica question, and I am not sure where to post it, so I'll just try to post it here. I am trying to graph the intersection of the planes y=3 and z=5 in 3D coordinates, but am not sure how.

From cosmology, ##H^2 = \frac{ρ}{3M_p^2} = \frac{1}{3M_p^2}(½\dot φ^2 + ½m^2φ^2)## Suppose ##V(φ) = ½m^2φ^2## where ##ρ## = density ##M_p## = Planck mass I want to graph ##H## vs. ##φ## but there is a ##\dot φ## and I know this is a differential equation, can somebody help me what to do here?

Is there an original manuscript available? The first published edition is available online.

Sometimes I include Mathematica code. Is is possible to include this option when including code in the thread for the language option? For example, would be nice to have a heading as "Mathematica" in the following code insert rather than "text": my mathematica code

I'm very new to Mathematica/programming and I want to do a theoretical calculation using Mathematica, suppose I have, ##Y=CX,~~~C=constant## Now, I want to plot Y vs. X but X should run at every point since every point is a solution for Y, how should I do this? Before, I was thinking maybe I...

Homework Statement I am a rookie to the QFT extension in Mathematica called FeynCalc, and tried to use that into solving some quiz. Soon I met a problem upon some condition presented in a problem which declares an relation of two same tensor with different indices results in some value when...

Hello to all. I've been trying to plot some graphs on Mathematica but I have faced some troubles so far. I am working on this paper by Lattimer on binary systems: https://arxiv.org/abs/astro-ph/0002203 I am trying to reproduce Figure 11 but something seems to go wrong. Here's what I have...

Homework Statement The problem I'm having involves looking for a specific formula for the probability of matching a deck of playing cards via the result of a shuffle. I want to know how many times I must shuffle for the probability of the shuffle matching one of the past resulting decks to be...

Homework Statement Use Mathematica to calculate the Gaussian curvature of the plane Ax+By+Cz=D, in which A, B, C, and D are constants and C≠0. Use the following data: Homework Equations The Attempt at a Solution First I found the line curvature. As here: That code gets the result = 0...

Mathematica is fully functional for daily astronomy data analyzing works, and it is much more convenient than python, so why can't them use Mathematica instead of python? It's like when you have warp drive you still travel through space using chemically powered traditional rockets, which is...

Hello physicists, Pretty new to Mathematica here. I'm looking to verify that $$P(s,\tilde{t}|_{s_0}) = 2\tilde{b}_{\rho} \frac{s^{\alpha+1}}{\check{s_0}^{\alpha}}I_{\alpha}(2\tilde{b}_{\rho}s\check{s}_0)exp[-\tilde{b}_{\rho}(s^2+\check{s_0}^2)]$$ Is a solution to...

I need to define a function that integrates a function in some interval and returns its numerical value. I am not allowed to use built in functions for integrating in Mathematica. This is my code that won't work: http://pokit.org/get/?93856fe8f2070ba781028f8634b9ac3a.jpg This is a code from a...

As I found on many websites, they suggest to use Chop[]. I tried that already but it doesn't work. This is my output. {{2 (Conjugate[ I.0] I.0 + (Conjugate[I.0] + Conjugate[Subscript[v, 1]]/Sqrt[ 2]) (I.0 + Subscript[v, 1]/Sqrt[2])) Subscript[\[Lambda], 1] (Conjugate[I.0]...

Hello can anyone recommend me a good mathematics package for solving the Einstein Field equations. You know one that can easily compute covariant derivatives and calculate the Reinman curvature tensor and can also minimize the Einstien Hilbert Action?

I have an integration that doesn't have a solution in the table of integrals. So, I evaluated it using Mathematica using the command NIntegrate. However, when I compare the result with Monte-Carlo simulations, there is a very small constant gap between the two curves. Is it because of the...

Hello, I have the following code in Mathematica, and it gives the following error: NIntegrate::ncvb: NIntegrate failed to converge to prescribed accuracy after 12 recursive bisections in x near {x} = {0.000156769}. NIntegrate obtained 0.21447008480474927` and 5.637666621985554`*^-13 for the...

I am currently a complete beginner to Mathematica (in fact, to programming in general) I have done adequate research about books for general books on Mathematica, but I would like to find a book that focuses mostly on graphics, animations, demonstrating physics and the like. For example, while...

Homework Statement Imagine a chain with ##n## links across a river. Now imagine, the chain is in a straight horizontal line at time ##t=0##. The problem wants me to calculate the movement of the chain links (center of mass) due to the gravity field. There are other forces in the system but this...

Hello! I let Mathematica run the following command: Solve[16 x^4 - 40 a x^3 + (15 a^2 + 24 b) x^2 - 18 a b x + 3 b^2 == 0 && 5 a x - 4 x^2 - b > 0 && 15 a x - 20 x^2 - 3 b < 0 && 4 x^3 - 8 c x^2 + 5 a c x - c b < 0 && a < 0 && x < 0 && c < 0, x] It displays a solutions in function of Roots...

Hey, I have this problem where mathematica doesn't show certain symbols (greek letters for example). In my current working document I have introduced other symbols but in the end it'll become a mess because several variables show up with similar names. When I export as pdf it does show the...

I want to evaluate $$\int_{a+b-c}^s\,\text{d}x\, \frac{(-x+ab/c)^{\epsilon}}{(x+c-a-b)^{\epsilon+1} (a-x)},$$ where ##a,b,c,\epsilon## are numbers, and to be treated as constants in the integration. I put this into mathematica and an hour later it is still attempting to evaluate it so I aborted...

Hi all, I have problem with regard to ill-conditioned linear system of solving sets of simultaneous equations using Mathematica program. I have tried my best to find a way to solve this but none was successful. I got results from m =1 and n =1 until m = 7 and n = 7, i,e. the systems are...

Hello! I'm currently working with Maple but I do not really like the program. Is there someone with Mathematica who can run this system? $$\left \{ \begin{array}{ll} 16x^4-40ax^3+(15a^2+24b)x^2-18abx+3b^2 = 0 \\ 4x^4+5a s \sqrt{v} x^2 - 8 s \sqrt{v} x^3 - b s \sqrt{v} x > 0 \end{array}...

Hey, I'm unsure why the following returns an error: Any ideas on how to fix this?

So, I'm trying to plot a 3D "dipole" (an arrow with a small torus around it basically) in mathematica, and want to rotate it according to Euler angles... I use this code for the rotation matrix: rot[a, b, g] := RotationMatrix[g, {1, 0, 0}].RotationMatrix[b, {0, 1, 0}].RotationMatrix[a, {0, 0...

I recently plotted a piecewise function: Plot[Piecewise[{{1 - Exp[-.002*t], 0 <= t < 120}, {-Exp[-.002*t] + Exp[-.002*(t - 120)], 120 <= t}}], {t, 0, 5000}, PlotRange -> {0, 0.25}] I then defined the function which I am calling q[t_] as follows: q[t_] := Piecewise[{{1 -...

Homework Statement I've entered the following piecewise equation into Mathematica: Plot[Piecewise[{{sin (t), 0 <= t < \[Pi]}, {5 + 5 cos (t) + sin (t), \[Pi] <= t < 4*\[Pi]}, {10 cos (t) + sin (t), 4*\[Pi] <= t}}], {t, 0, 20*\[Pi]}] But I am getting a blank graph in return. I've proofread my...

Hi everyone, I'm new to Physics Forums and to Mathematica, as well as Jacobi Identity. In any case, I was wondering on how I may use Mathematica to solve various Quantum Mechanics related problems through commutators. Like if it's possible to find out what is the form of a particular commutator...

I've been trying to read Newton's Principia Mathematica, sth I've always wanted to do since college. i'm familiar with the physics concepts and necessary mathematics involved, but often I found it's very hard to read the book, sometimes to the point that I'm totally lost as what Newton's...

I had posted a question in the mathematics forum about some conceptual issues I was encountering while reading the book, but now I realize as I read on that I may need a dedicated thread for asking questions about the book. So I am asking two things in this thread. Firstly, I am asking someone...

I know that this book is both fundamentally flawed and an extremely important book. I got it for Christmas, and I kind of view it like a whetstone for my mind. I'm taking my time and I won't turn the page unless I understand everything beforehand. I've been on the same page for a little bit...

Hi I am new at the mathematica software i would like to find way to improve my skils

Hello, I have to solve the following integral in Mathematica but although I don't get any mistakes the value I get is <10^-700 which can't be right! For the following values b=0.052868 c=0.998047 g=0.00762712 s=0.902416 I have to solve the following: Fx =...

Hi, I was wondering if it's possible to colour the rows and columns of a matrix in mathematica. I have received help from another forum and the code of my matrix is the following: Rasterize@ Style[MatrixForm[{{n, -1 + n, -2 + n, \[CenterEllipsis], 1}, {2 n, 2 n - 1, 2 n - 2...

I have to find a unitary transformation that takes me from one quantum state to another (or if there is such a transformation), given the two quantum states in matrix form. The matrices are huge (smallest is 16x16) , so doing it on paper is not an option. Does anyone know how I can do this in...

Hi! I'd like to discuss your experiences with pen and paper vs software. Especially young people are welcome to join the discussion :) I'm wondering if there are people who do *most* of the symbolic calculations on a computer. I am very familiar with pen and paper and I've been wondering...

I have nine sets of data with x,y coords that are the position of a particle. I can ListPlot the particle positions on a single plot, but, I want to animate this. ListPlot[{mydata1, mydata2, mydata3, mydata4, mydata5, mydata6, mydata7, mydata8, mydata9}, PlotRange -> {{-1, 20}, {-1, 20}}] I...

Did you guys self study or take a class?

How well do you need to know it if you're a grad student? Isn't it nothing more than an "calculator" in that you don't "make" anything, just use it to solve integrals and such? Edify me.

What are the differences and pros/cons of each?

Hello Everyone. I'm returning to college to earn a degree in physics 15 years after getting a BA in English. I took calculus almost 20 years ago and used a Ti 85. I've noticed that some graphing calculators have CAS integrated, which I've never used, and I'm keen to get one for my physics and...

Does any know how to perform Kaluza-Klein reduction via mathematica? The task becomes very tedious if the job is done manually when successive reductions are done.

Hello, I've collected data with pairs of { resolution, filesize in bit }. Now I would like to use a ListPlot to visualize the data in mathematica. My problem is now showing the x-asis two times. One for the filesize in bit (above) and the other for the filesize in KiB (below). ListPlot[...