Questions tagged [physics]
Questions related to the application of Mathematica to problems in physics.
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NDSolve over derivatives of Heaviside function
I am trying to numerically solve for the strain of a Maxwell material in response to a step stress. The governing equations are $$\dot{\sigma} + \sigma = \dot{\varepsilon}$$ and I want to find $\...
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Lens on a map. Realistic imitation of magnifying glass on images with text and other small features
UPDATE: Code from this post was used for video generation here:
Cinematically moving a lens over images: magnifying glass effect in videos
I am trying to create a magnifying glass effect for images ...
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Speed Up Plotting of Mathieu Equations
I am trying to plot Mathieu Functions, running for an hour without a result. Here is my code:
First define the relevant physical constant:
...
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Metric pertubation in xAct
I start to learn xAct. Following this thread:
expanding-the-riemann-tensor-perturbation I noticed that xAct set a default perturbation to the metric by:
...
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Simplifying the Einstein tensor in case of a perturbed FRW metric
I use the code in this thread's answer:
(Calculating Einstein tensor components in Kaluza-Klein model)
to get the Einstein tensor components of a four-dimensional Kaluza Klein model.
But instead of ...
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Creating a plot for a summation function
I have this potential function which I believe is representative of a grounded cube in a 3D plane. I'm not entirely sure if this is it, but here is the general solution of the function:
v(x,y,z) = G(...
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Tracking сode performance with the conservation of energy
I am working with the Momentum Principle as defined by Chabay and Sherweood in their text Matter and Interactions (pf = pi+Fnet dt). The following code has been created to automate the process of ...
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Calculating Einstein tensor components in Kaluza-Klein model
I try to calculate the Einstein tensor of Kaluza-Klein model from this paper. It is given by Equation (55)
$
G_{\alpha\beta} = \frac{\nabla_\beta (\partial_\alpha \phi)}{\phi} - \frac{1}{2\phi^2} \...
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Evaluate the time average of Mathieu functions
I defined a function composed of Mathieu's periodic functions:
...
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Modelling projectile with lift and drag forces
I am trying to model a projectile motion with lift and drag forces.
I have written the code below, solved for $y$ and $x$, and tried to plot it.
However, I don't know how to implement the fact that ...
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About using series function
I am using Series function on (1/z)(-k^2)^z. Up to z^0, the function gives me 1/z + Log[-k^2]. But in the standard textbook on QFT, it turns out the expansion should give 1/z + Log[k^2/mu^2] -i*pi up ...
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How can I use Gaussian elimination for finding QNMs in this code?
I am reading the article Scalar-gravitational perturbations and quasinormal modes in the five dimensional Schwarzschild black hole. I want to reproduce the value of the quasinormal frequency with $l=2,...
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How can I solve unintegrated Boltzmann equation fast and robustly?
Consider the following integro-differential equations (the unintegrated Boltzmann equations for ultrarelativistic particles in the expanding Universe):
$$
\left(\frac{\partial}{\partial t} - H p \frac{...
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Solving Geodesics from Christoffel Symbols
I am somewhat new to using Mathematica and I am facing difficulties with a specific problem related to the geodesics of Einstein's field equation in a vacuum.
The metric I am working with is derived ...
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Finding the coefficients of a decomposition of complicated expression into products of special functions
I have the following expression which arises while studying minimal models in CFT. The 4-point amplitude of scalars is given by
$$G(z,\overline{z}) = ((1-z)(1-\overline{z}))^{\frac{m-1}{m+1}}\mathcal{...
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