Questions tagged [physics]
Questions related to the application of Mathematica to problems in physics.
1,028 questions
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Problem with evaluating the Trace of Hadronic tensor of spin 3/2 particle
I am trying to evaluate the Diractrace using Feyncalc package. The expression involves projection operator 'ab' which comes from completeness relation of spin 3/2 particles (Delta-). I am having some ...
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While solving set of differential equations with NDSolve, I got NDSolve::initf: The initialization of the method NDSolve`StateSpace failed
Now I'm trying to solve partial differential equation by discretizing spatial coordinate. These equations are a kind of fluid equation and the fluid is annihilated at the x=0.
The variables are matter ...
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Issue with plotting piecewise function
I tried to plot the critical meniscus height of a liquid near a vertical rod (pulling upward) (radius, $r_0$) using the nondimensionalized equation (as $z=y/r_0$ and $r=x/r_0$) given in this paper, ...
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Solving a nonlinear partial differential equation using method of lines
I am trying to reproduce Figure 5 of this paper by using the following Mathematica code, which uses the method of lines for NDSolve. Unfortunately, I am not able to ...
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Can we merge a piecewise with 2 interpolating functions into one interpolating function?
I have the following Mathematica code:
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How to find equation of motions from lagrangian with partial derivative terms?
I am trying to find the equation of motions for the lagrangian given in Eq(22) of this paper. For this purpose, I use the following Mathematica code:
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Problem with constructing the trajectory of a particle in a pulsating field obtained numerically by solving a wave PDE
I model the propagation of a pulsating wave. Below is a system of partial differential equations with free boundaries (Neumann conditions), as well as a pulsating component.
Individual components of ...
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Level spacing Spectra and Entanglement Entropy of Spin-Chain
The hamiltonian
$H=\sum_{i=1}^L S_i.S_{i+1}-h_iS^z$.
It is a periodic $S =1/2$ Heisenberg chain in a random magnetic field, $h_i$ drawn from a uniform distribution $[−h, h]$.
The ratio of consecutive ...
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Using indices to define the metric and Ricci tensor
This question is related to a previous thread
Calculating the covariant derivative of Ricci scalar.
I try to write MA code to define a new modified Einstein tensor:
$$ G'_{\mu\nu} = G_{\mu\nu}- \frac{...
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Simulating k-many 'Electrons' with 'Repulsion' on 'Atoms'
Perhaps a better title would be:
"Simulating k-many Moving Points with Distance Contraints on Sphere-like Cages"
because I am not concerned about representing anything physically real. This ...
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How to estimate and replace values in a signal? [closed]
I have this data:
j={{0.,0.46154},{0.02,0.96675},{0.04,BLINK},{0.06,BLINK},{0.08,BLINK},{0.1,BLINK},{0.12,BLINK},{0.14,0.95638},{0.16,BLINK},{0.18,BLINK},{0.2,BLINK},{0.22,0.97462},{0.24,BLINK},{0.26,...
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Seeking Recommendation on Time-Independent Schrödinger Equation Solving Method in Mathematica
I am seeking to solve a Time-Independent Schrödinger Equation using the Mathematica Platform. I will detail the problem below:
Scaling Constant is "K." This is calculated by the formula (2 m ...
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Seitz symbols for crystallographic symmetry operations
In crystallography, the Seitz Symbol is a standard notation for describing symmetry operations in space groups. Its core idea is to decompose a symmetry operation into a combination of point ...
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Time Independent Schrodinger Equation
I am attempting to run the time-independent Schrodinger equation for two states of a molecule and then find the overlap integral (called the Franck Condon Factor) for the states.
This is where: Hbar ...
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Parametric plot related to black holes
I am trying to reproduce the top left figure 5 with $q = 0$ from the manuscript
https://arxiv.org/pdf/1707.09521 . In this case, for $\theta = \pi/2$ in equation 52, $\alpha$ is equal to equation 45 ...
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Should I use ChatGPT and Wolfram Mathematica as a student? [closed]
While solving mathematical equations in physics and STEM, can we take help from ChatGPT (in the same way as one would use a calculator or log tables) and use Mathematica packages instead of using pen ...
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Time evolution operator for hamiltonian to find evolved wavefunction at different time step
I have a wavefunction which is the eigenvector of the smallest eigenvalue.
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Discrepancy in Calculating Trace Expression for Fermion Scattering Using FeynCal
I am writing a code in Mathematica using the FeynCalc package to calculate an expression ( Y_1 ) that is required to evaluate the differential cross-section for the scattering of two massless fermions ...
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Contract::fail Error in FeynCalc When Using Calc[FullSimplify[Y1]] /. momentumRules
I’m working on a quantum field theory calculation in Mathematica using FeynCalc, and I’m running into the following error:
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Two graviton two scalar vertex using FeynRules package
The model file I have used for generating two graviton two scalar vertex using FeynRules package doesn't give me the correct vertex. The correct vertex should have 18 terms in its full extended form. ...
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How to model time series with Fourier series?
I want to apply Fourier series to a time series and then compare its estimates to the actual values. The data is related to the monthly rainfall of a city from 2000 to 2023. I used the following ...
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Perturbations around Minkowski in xPert
I want to be able to perform perturbations in Minkowski space using xPert, xTras, and of course xAct. I am trying to re-create the parity even term found in this paper: Causality Constrains Higher ...
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Uneven voltage/current density distribution using FEM [closed]
I am trying to use the FEM tools in order to generate a current density mask for a trapezoidal racetrack. The voltage input is a 1 unit wide x 2 unit tall pad that I defined in the Laplacian equation. ...
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Jagged results from using NDSolve
I am trying to reproduce results from this paper, which involves solving a fourth-order differential equation.
After setting the various parameters:
...
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Solving a second order differential equation with parity symmetry
I am trying to reproduce the Figure 2 from this paper.
The code that I am using to solve the differential equation is given below:
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