# Tag Info

### Simulating solar system with Newton's law

You need to use a better numerical method. Euler’s method is notoriously bad for orbital mechanics because the numerical errors always accumulate. In particular, Euler’s method does not conserve ...
• 104k
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### Does quantum mechanics allow you to simulate chemical reactions in software?

Yes, it is possible. Working with pure quantum mechanics means you will need to solve the many-body Schrödinger equation, which has no exact solution, so some approximation must be done numerically. ...
• 459
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### The Functional Determinants in Peskin and Schroeder (Eq.9.77)

The problem seems to be that Mathematica here evaluates ${\rm Log}[\text{matrix}]$ by taking ${\rm Log}$ of each matrix element, which is not the correct mathematical definition of the complex natural ...
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### Does quantum mechanics allow you to simulate chemical reactions in software?

Yes, this is possible -- I used to study it in undergrad, actually. I would say that the prerequisites are probably a few semesters of quantum mechanics -- enough to learn concepts like Born-...
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### Why does my binary star simulation only work for equal masses and initial speeds?

It simply looks like your initial condition causes the system to move through space. You need to work in the centre of mass frame. Set $$m_1v_1=-m_2v_2$$
• 11.7k
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### Potential function - numerical simulation

If you're trying to simulate a 2D solution of the Laplace equation (which is the only unambiguous reading of your post as currently stated; if that's not what you're doing then you should clarify your ...
• 134k

### How do theoretical physicists do their calculations?

Depends on what you are doing. The nature of work in theoretical physics is as varied as the theoretical physicist. Most likely, the work takes on different forms. For the most simple calculations, ...
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### Simulator for trajectories of charged particles in electric fields?

You may have a look at agros2d which could simulate electrostatic fields determined by various boundary conditions and then charged particles in the electric field. A similar case as you mentioned in ...
• 2,135
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### Metric tensor calculation tool?

Solving the Einstein field equation is notoriously hard. When Einstein originally calculated the GR contribution to Mercury's perihelion precession (the famous $\sim 43$ extra arc seconds per century)...

### Numerical Tools and Related Resoures for Bohmian Mechanics

I don't believe anyone's released any compiled tools or libraries specifically for Bohmian simulations, but for a few simple examples in Python using RK4, Dane Odekirk has an excellent git repository ...
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### Laplace's heat equation equilibrium functions

Your iterations are converging to a solution of Laplace's equation, $\nabla^2T(x,y)=0$, with your boundary conditions. This equation can be solved exactly in a rectangular area, with $T$ being ...
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### Useful resources and softwares for computational astrophysics

At least to address the computational aspects of the turbulent, compressible flow solver parts, I will quote Kyle Kanos: On a more programmatical aspect, Toro's Riemann Solvers and Numerical ...
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### On using Python to solve Time Independent Schrodinger Equation, the eigenfunctions have their values "pushed" to one of the boundaries?

Your script looks fine on first glance. Your problem is that your eigenfunctions are the columns of your eigFunc1 Matrix and not the rows. Use this to plot them. ...
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### Simulator for trajectories of charged particles in electric fields?

Simion Directly from the product website: SIMION is a software package primarily used to calculate electric fields and the trajectories of charged particles in those fields when given a ...
• 4,040
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### Yet another question on time dilation on basic special relativity (with code)

When in doubt, do a Lorentz transformation. There two events $(t, x)$ going from event $A$ to event $B$: Leaving Earth: $$A = (0, 0)$$ Arriving at destination: $$B = (L/v, L)$$ So the elapsed time ...
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### Matrix representation of the Clifford group

There are algorithms to generate all elements of the Clifford group for a specified number of qubits. Here are a few implementations: Algorithms that can enumerate an arbitrary Clifford operator ...
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### Applet mentioned in Griffiths' Quantum Mechanics

It looks like the URL (now broken) that was printed in Footnote 7 of the book led to one of "Mark's Quantum Mechanics Applets". These applets survive at this webpage. The specific applet that ...
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### Smartphone accelerometer detects braking on long turns

If we are talking about high lateral acceleration sustained for a significant time, the car may not remain aligned with the direction of motion. That is the velocity vector may not be pointing ...

### Unwanted frequencies in sawtooth tone

I can't be certain that this is generating your peaks, but any tone that starts and stops won't be 100% pure; a pure tone has no beginning and no end. Consider a tone that starts at $0$ at $t=0$, ...
• 22.7k
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### Unwanted frequencies in sawtooth tone

Your sampling rate is 48k at 55Hz, so each period is 872.73 samples. The size of your FFT is 65536. It fits 75.093 period of the signals. The algorithm takes 75 periods to plot the chart. This leaves ...
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### Conformal field theory using Mathematica

Conformal Bootstrap A page by an associate professor at Brandeis University has provided a notebook to implement the Virasoro algebra in Mathematica, and compute conformal blocks. It can also teach ...

### How to code Tensor Networks?

An online platform where you can learn about tensor networks, their definitions, index juggling, Python/Matlab/Julia codes describing MERA, TRG, TNR, Exact Diagonalization is -- https://www.tensors....
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### Creating a pendulum simulation in C#

Numerical integration of the equations of motion of a pendulum faces two separate but interconnected problems. The first problem is common to every Newtonian dynamical system. It is connected to how ...

### Solution techniques to the Einstein Field Equations

It makes no sense to try to solve these equations given just the equations. The field equations relate the distribution of matter in some region of space, given by the energy momentum tensor \$T_{\mu\...
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### Phase space density behavior in finite volume

Here's a picture of your initial phase-space density. Position is the horizontal axis and velocity is the vertical. I've also included plots of the velocity distribution (left) and the spatial density ...
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### Software/apparatus to measure wavelength of visible light

This depends largely on what apparatus your school already has. But every school should have a good diffraction grating and a large white screen. You can then do a diffraction experiment and take ...

### How to plot Joukowski airfoil?

Here is a Python code for generating the streamlines of the flow past a Joukowski airfoil (static plot and animated streamlines, asociated to a rotating airfoil): http://nbviewer.jupyter.org/github/...
• 139
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### What are the differences between the Jetphox, Pythia and Herwig event generators?

Old question, but very briefly the difference is that JETPHOX and other "matrix element" (ME) partonic event generators simulate the hard process only, resulting in a partonic event with only a few ...
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