Questions tagged [simulations]

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Elastic constants, transformation/basis change $P21/a\to P21/n$

I just calculated the stiffness tensor for a given material (a monoclinic molecular crystal) using molecular simulation. When trying to compare my results to published experimental results I found ...
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2answers
74 views

How to integrate over a timestep in a mass-spring model? [closed]

I'm writing a simulation of a block of matter using a "mass-spring" model, where the matter is modelled as a 3D lattice of point masses, where each point is connected by springs to the (up ...
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27 views

How is the Overlap Distribution Sampled for Spin Glasses Computationally

To study the phase transition of spin glasses, a commonly used order parameter is the Binder's parameter, defined as the 4th order cumulant of the overlap distribution $P_J(q)$, where $q$ is defined ...
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1answer
22 views

Simulated points in a closed 2D shape all moving to the edges. Is this how electrons accumulate on the surface of a wire?

I was working on a program that generates random tiles in a given shape. To do this I generated random points inside the shape and would use them to color the tiles. However, after noticing clumping ...
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1answer
63 views

Calculating orbital path of a planet around a fixed body in a deterministic way given starting conditions

I am making a simulation of the solar system in the unity game engine. A planet is orbiting a stationary star for now using Newton's law of gravitation where $F = Gm_1m_2/r^2$ for the orbit (force is ...
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25 views

Star formation rate in different galaxies

I was looking for some scale to compare my result of star formation rate and see if it is moderate or high or low. But I couldn't find any scale. Is there any paper related to such scale where Star ...
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24 views

Scattering MC toy model

I would like to make a scattering toy simulation as a computational physics project. I'm having issues visualizing which parameter of the scattering function I need to compare with the randomly ...
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2answers
74 views

Orbit of Celestial Bodies

To give some insight, I'm creating a simulation, with gravity, planets, forces... And I would like to increase performance, by not doing unnecessary calculations. I could know what calculations, to ...
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3answers
81 views

Computing the $x$-$y$ position of a vehicle for constant acceleration

I want to very simplistically plot the $x$-$y$ position of a vehicle in 2D that can accelerate/brake and drive a constant speed while turning etc. The basic equations for determining the position for ...
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37 views

Angular acceleration component of linear acceleration

Assume I have a mass M attached to a spring which is attached to a fixed point in space, X. The mass has an arbitrary linear acceleration a applied to it, which means the spring can both be extending/...
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1answer
76 views

Resonant tunneling for wavepackets, simulation - what exactly is happening here?

I have been learning various ways to solve TDSE and naturally, wavepacket motion seemed like a good test case to check the algorithms. Then, of course, I wanted to see one of the most interesting ...
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1answer
96 views

Is there any point in doing Monte Carlo on classical 2D Ising spin systems? [closed]

The partition function of a classical Ising spin system with arbitrary bonds on any planar graph can be evaluated in polynomial time, through the FKT algorithm. And if I understand correctly, this ...
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1answer
148 views

Numerical discretization and the Schrodinger equation, for a simulation

i'm solving numerically the Schrodinger time dependent equation, in this case simplified to one dimension, and i don't know at all how to discretize it, or if what i have done its okay. $$i\hbar\frac{\...
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1answer
42 views

2D rocket lander vectors (gamedev)

I'm writing a game prototype with simple 2D Physics, of a 2D rocket "lander" style. Let's assume that there is a downward gravity of (0, -1). The rocket has an up-vector (that can be also ...
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1answer
33 views

Cases for reasoning about mass transfer

I'm doing some simulations of a 1D system with diffusion. One boundary has a no-flux boundary condition, while the other boundary has a prescribed-flux boundary condition with a specified mass ...
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1answer
54 views

$N$-Body Solar System Simulator - Why are there inaccuracies in the $x$ plane but not the others? [closed]

I have written a basic $N$-Body simulator that simulates the motion of the planets in the solar system. The system reads the positions and velocities of the planets at a given time, measures the time ...
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3answers
223 views

How can I calculate the final velocities of two spheres after an elastic collision? [duplicate]

I have two spheres in 3-dimensional space. The mass and initial velocity of each sphere is known. If the spheres collide elastically, how can I calculate their final velocities? The spheres do not ...
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1answer
59 views

Questions About Implementing Rotational Kinematics in a Game

I'm making a videogame where the player controls a spaceship in a 3d environment, but the catch is the physics are realistic. The thing is, I'm struggling with 3d rotational kinematics. At first I ...
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2answers
171 views

How to know when a body completes an orbit?

I'm simulating a solar system, and I would like to know when a body, has completed an orbit around another. Is there any specific formula for it? As shown in the picture, the orbit is elliptical, ...
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1answer
194 views

Why are fluid simulations so hard?

Fluid simulations solving the hydrodynamic (HD) or the magneto-hydrodynamic (MHD) equations are very useful in physics, the latter being particularly useful for modeling plasmas. Of course these ...
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1answer
64 views

Why is the production of turbulent kinetic energy maximum in the lowest layers of the turbulent boundary layer?

I have been studying the basics of CFD from a book titled 'An Introduction to Computational Fluid Dynamics' by H.K. Versteeg. In the turbulence modelling section, the author shows how the production ...
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24 views

Are there any multi-physics with magnets and gravity software simulators?

I'm looking for something like SolidWorks / Autodesk Inventor but with electromagnetism built-in. Do you know of such software?
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55 views

Mathematical model of the compression of a syringe by means of the action of a motor

Does anyone know how I can get a hydrodynamic model of the compression of a syringe by means of the force of a motor ($ F_ {M} $). Where $ F_ {atm} $ is the force due to atmospheric pressure, $ F_ {r} ...
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2answers
226 views

How can the universe be a computation?

A few physicists (or computer scientists) take it for granted that the universe is a computation. However, I am not able to understand how the universe CAN be a computation in the first place. I come ...
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28 views

Equations of motions vs Verlet: Collision ignored?

I initially coded my simulation using the standard equations of motions, but as is known, it ended up being quite unstable, even if it technically worked. If we take x(t) to be the position-function ...
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22 views

CoilGun analysis method

I want to simulate a CoilGun system in python. Assume The system circuit as a simple RLC circuit It is the method that I used : I used FEMM software to get force & inductance data at different ...
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47 views

In Numerical Relativity (Neutron Star Mergers for example), the Metric is constantly changing. What does the "time" in each frame measure?

Hi there and really sorry for bothering you! Recently I have begin to studing GR and I have found some simulations regarding Neutron Star Mergers. Take a look at this video for example: https://www....
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28 views

Impulses in a Collision

The question I have is that of computing the impulse in a collision between two objects in real life (or in a scenario that is very close to real life). I wish to simulate collisions of objects of ...
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2answers
96 views

Could the world be represented as binary? [duplicate]

The Matrix the movie regards the whole world as being binary and us living in a computer simulation. Could the world be represented as binary similar to a matrix or is that not practical give quantum ...
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105 views

What is the correct way to perform numerical integration over Brillouin zone?

Let us have an integral $I$ over the first Brillouin zone (BZ) of a 2D lattice. $$I = \int\int \Omega(k_x,k_y) dk_x dk_y$$ where $\Omega(k_x,k_y)$ is some function (let's say it's Berry curvature). ...
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45 views

de Broglie vs Schrodinger models: Why is the IR spectra different in PhET simulation?

I was playing around with the PhET simulation "Models of the Hydrogen Atom", https://phet.colorado.edu/en/simulation/legacy/hydrogen-atom . In it you can simulate a hydrogen atom's electron ...
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1answer
68 views

Numerics for Bose-Hubbard model

For the Bose-Hubbard model, we know that there are the Mott insulator phase with $\langle a_i \rangle = 0$ and the superfluid phase with $\langle a_i \rangle \neq 0$. However, when we are trying to ...
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1answer
45 views

How would you go about scientifically comparing the physics of a game and real-life through gravity?

A bit of a hypothetical situation for y'all here. Let's say you want to test a video game's accurateness with regards to its physics; by seeing how closely the game's physics matches up with real-life ...
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17 views

What distribution shape does this broadband signal have if the bandwidth changes?

In the Lumerical tool, I'm simulating a setup using a broadband dipole signal. It is (or should be) centered at $\lambda=$ 922.5 nm and has various bandwidths $\Delta \lambda$ for different ...
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0answers
22 views

Vehicle Drive Model - wheel and engine angular speed approach

I am trying to create a simple car simulation in 2D in Unity3D, I'm having a hard time figuring out the right approach. Say I have given the throttle percentage, I know the current engine's and wheels'...
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51 views

What factors would cause a change in oscillation period as a result of a change in mass of pendulum bob? [closed]

I'm running an experiment in a video-game simulator (ish) called 'G-MOD'. I setup a typical pendulum setup, and measured the change in the period as a function of the pendulum's mass. I obviously ...
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17 views

Modeling of Spatial Filtering of aberrated beam (~10mm) with Pinhole (~10μm) in 4f-Configuration -> size-constraints

I am trying to simulate a spatial filter in 4f-Configuration with an aberrated input beam to get a feeling for the remaining intensity and wavefront error depending on the pinhole size & ...
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23 views

What is the number of target particles per unit volume in human skin when modeling the Raman Effect?

Question I want to leverage existing studies on the Raman behavior of human skin to build simplified, zeroth-order models. To do this I want to find the intensity of the Raman signal per unit volume ...
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1answer
34 views

Height oscillations in orbit induced from lunar gravity

I am trying to numerically solve the orbit of a space probe around the moon in a non-spherical gravitational field . $ \Large \begin{align} \frac{d^{2} x}{dt^2} = - \frac{G M x}{(x^2 + y^2)^{3/2}} - \...
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1answer
66 views

Modelling sky noise using a 2D array with plane waves

I have a question about modeling sky noise which should be filtered by a spatial filter 4f system. My approach for this task is to use a 2D array with random amplitude values and another 2D array that ...
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1answer
119 views

How can I calculate the gravity constant $g$ of a video game, that is displaying frames at $60\,\text{Hz}$, in relation to $9.8\,\text{m/s}^2$? [closed]

How can I calculate the gravity or "$g$" of a video game displaying frames at $60\,\text{Hz}$, to $9.8\,\text{m/s}^2$? Please let me know if you need any more parameters or details or if ...
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22 views

Which volatile ices are hardest below 100 K?

In the context of planetary science, some elements and compounds are informally called volatile instead of refractory, such as H2O, HCN, CO2, NH3, HCHO, CH4, CO, N2. At conditions found near planetary ...
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22 views

Which is the Best Free Physics Simulator that can simulate the dropping of a ball? [duplicate]

We were asked in class to use a physics simulator beforehand to test the conditions of an experiment we are going to do and save it to use in our report. The experiment involves the dropping of a ball ...
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1answer
66 views

Reducing the Hamiltonian size by using a symmetry to speed computations

Say I have some Hamiltonian $\mathcal{H}$ that describes a 1-D spin chain (i.e. Heisenberg model) which has a number of compatible symmetries $\{\mathcal{O}^i\}$ (i.e. total spin...etc). For all $\...
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2answers
72 views

Using Runge-Kutta method with measurements of acceleration (what to do with half-steps?)

I'd like to perform a short-time motion estimation based on measurements from an Inertial Measurement Unit. If I use the Runge-Kutta method, I will need to compute the k values at half-time steps (Ref)...
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51 views

Numerical integration of overdamped Langevin equation: explicit methods?

Assume we have a generic overdamped Langevin equation $$ \frac{d {\bf{x}} }{dt} = {\bf{f}}({\bf{x}}) + B {\bf{w}}(t) $$ where $\bf{f}$ is a deterministic external (and fixed) force field (non ...
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1answer
59 views

Evaluating $C_v$ for one mole of $H_2$ molecules in a quantum simulation

Given an ensemble of $N$ diatomic molecules, we know that the rotational partition function is given by $$Z_r = z_r^N$$ where $$z_r = \sum_{l} (2l+1)e^{-Kl(l+1)}$$ where $K = \beta \hbar ^2 /2I$. I ...
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1answer
50 views

How Would Projectile Motion Be Described in Non-Euclidean Space?

If I and a friend found ourselves in a world described by spherical geometry (as simulated in this linked video https://youtu.be/yY9GAyJtuJ0 ) how would the kinematics equations need to be augmented ...
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2answers
149 views

Bond Orientational Correlation Function

Firs this question has some similarity with Bond order correlation function and Bond Orientational Correlation Function - how exactly to calculate but its a little bit different , so having those ...
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1answer
266 views

Understanding details of the chromatic aberration depicted in this simulated image from NASA

Phys.org's The detection of phosphine in Venus' clouds is a big deal, and here's how we can find out if it really is life contains part of a NASA/JPL-Caltech image which is on the cover of Aerial ...

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