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### Curvature of a particle move

I'm simulating a particle movement following a normal distribution. How this is done: My particle has a constant speed v and every step the particle move, I ...
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### Modeling a potential well

I attempted to simulate the interaction of a moving particle and a potential well in Mathematica. The particle should experience a force of -$1/r^2$, if the equation for the potential well is -$1/r$. ...
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### How to get the new direction of 2 disks colliding?

I'm developing a 2D game including collisions between many disks. I would like to know how I can get the angle corresponding to the new direction of each disk. For every disk I have this information :...
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### Could there be a sort of “Molecular Destiny”?

Let's say we start with the Big Bang. Every bit of matter started from this event. Therefore, given EVERY variable (every particle, movements of particles, weights, times, etc) and an INFINITE amount ...
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### time step in kinetic montecarlo simulation

I have a doubt about how the time step is calculated in kinetic montecarlo simulations. One state with index $i$ is connected to other $N$ states, indexed by $j=1...N$, by transitions that happen ...
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### Monte Carlo with zero-temperature: trapped in a local minimum

I have a problem reaching the correct ground state while performing a Monte Carlo at zero temperature. Some parts of the system get trapped in a local minimum, and for getting the global one (the ...
When simulating a Langevin equation, how is a vertical potential barrier handled? I have the time overdamped evolution of the position $x$, described by $\gamma\frac{dx}{dt}=-V'(x)+\eta(t)$ where $... 2answers 114 views ### Center of mass chaotic in n-body gravitational interactions? I wrote a gravitational particle simulation. To prevent the particles flinging off out of the screen, I added a bit of friction (it also makes the animation prettier as particles spiral into one ... 1answer 298 views ### Local minima in Ising model in a Monte Carlo simulation Is there any way to check whether in a Monte Carlo simulation using Ising model is stuck in any (false) local minima of energy or not, particularly in 3D system ? 2answers 65 views ### Current Status of the Monte Carlo Sign Problem I've been reading about the Monte Carlo sign problem, and I am a little confused about its current status. Specifically, after reading this post When is the "minus sign problem" in quantum ... 1answer 98 views ### Damping a spring force I'm modelling particles in a system using a spring and damper force. $$F= kx -cv$$$x=x_i -x_f$, where$x_i$=centre of spring and$x_f$= displaced position. Above$x$is the displacement and$v$is ... 2answers 69 views ### How do I modify a 3-D simulation grid to be 2-D? I am creating a particle in cell simulation that models an electron plasma in a cylindrical container. Part of this process is assigning charge density to grid points based on the position of each ... 1answer 89 views ### Quantum Space Simulation There are a number of simulators, which simulate the macroscopic world around us (Space Engine: http://en.spaceengine.org/ comes to mind, but there is also Universe Sandbox). My question, does ... 2answers 177 views ### If you “disobey” the constraints of the Kramers-Kronig relations, what happens? Do you get non-physical results? If you "disobey" the constraints of the Kramers-Kronig relations, what happens? Do you get non-physical results? I am simulating reflection and transmission off/through a slab of material. I specify ... 2answers 556 views ### How to calculate velocities after collision? I'm currently writing a program for a particle simulator. One of the requirements is that the particles collide in a realistic way. However, I don't know how to calculate the final velocities. For ... 1answer 89 views ### Any FLOSS Monte-Carlo package for reactor physics? [closed] Any FLOSS Monte-Carlo package for reactor physics? Are there any Free and Open Source software packages for nuclear reactor processes simulation? Maybe, something similar to MCNP? 2answers 185 views ### How should I simulate the electric potential field from a wavefunction? I was interested in making what I thought would be a simple simulation of an electron encountering a positron by numerically solving the Schrodinger equation over several time steps, but I've run ... 3answers 138 views ### How much space to simulate a small Hilbert space? I'm thinking about trying to do a numerical simulation of some very simple QM problems. How much space do I need? To simulate the Hilbert space? I'd like to eventually simulate the absorption or ... 1answer 743 views ### How is acceleration computed in the leap-frog algorithm in computer simulations of particles? I am reading the book Computer Simulation of Liquids by Allen and Tildesley (here is another link). On page 80, the authors describe the leap-frog algorithm, which is used extensively in molecular ... 1answer 43 views ### Meaning of$\nabla_{\mathbf{p}_k} W(\mathbf p, h)$in PBF I'm reading this paper on Position Based Fluids and I couldn't understand the meaning of$\nabla_{\mathbf{p}_k} W(\mathbf{ p_i - p_j}, h)$in the equation 7 (see below). …the gradient of the ... 2answers 108 views ### Limitations of particle in cell method for high desnity plasma Are there any limitations of particle in cell (PIC) method for high density plasma? To be more specific, is modelling of a narrow channel of high density plasma possible or are there any limitations ... 1answer 199 views ### Problems implementing Lattice Boltzmann method I want to make a basic 2D implementation of the Lattice Boltzmann method (in javascript) to simulate gas/fluid flow, but I have run into some problems and I can't seem to find the cause of it. ... 5answers 110 views ### Is more lift always better? In the domain of aircraft, and more specifically powered flight, is there any case in which you wouldn't want the airfoil used to generate as much lift (and as little drag) as possible at a null angle ... 3answers 270 views ### Calculating vector to aim for moving asteroid (3D asteroid game) Considering we're in a 3D system of coordinates: our ship is at point A, motionless our ship can shoot bullets, the speed of which is known the asteroid is at point B the asteroid is moving on known ... 1answer 322 views ### Simulation of fluid flow using Euler equation I have been looking on Euler's equations for a while and can't grasp one thing. Suppose we have initial system state with volumes of fluid "hanging" in air (time is frozen and equal to zero), each of ... 1answer 189 views ### Simulating a 1-dimensional wave on (a segment of) an infinite line I'm trying to numerically simulate a 1-dimensional with a chain of linked harmonic oscillators as described here (the result can be seen here). The simulation behaves like a wave on a finite line ... 1answer 672 views ### How to model water flow with and without friction against other objects? I am interested in modeling water flow including boundary flow (with friction) against other objects in the path of the water flow. I'm not a physicist but I am interested to learn the relevant ... 1answer 1k views ### Simulating Gravity in 3D Game? Alright, I am writing a space simulator for a 3D game and I would like to implement gravity of objects into it. Is there a nice way to find a velocity vector which can be added to my engine output ... 2answers 2k views ### How to implement Heun's method to solve a 2nd order ODE? [closed] I am trying to simulate a soft body object by having a collection of points connected by springs. I also want to have the object bounce on a plane. I have been able to implement Euler's method to make ... 1answer 679 views ### Software for simulating supersonic aerodynamics [closed] Could you please suggest the software, where I can load my 3D model and see how it behave on various conditions (speed - preferably including supersonic, temperature, pressure)? Both free & ... 1answer 46 views ### Magnetic force and torque for 2D neodymium ball simulator I'm trying to write a simulator for neoballs. I'm doing only 2D for a start, in which each ball has a magnetic moment, m, that is in the x-y plane. The simulator will use time-step integration at 60 ... 1answer 63 views ### What does the solid phase in a two-dimensional system with Lennard-Jones potential look like? Consider a system of two dimensional particles interacting via Lennard-Jones pair potential: $$u(r) = 4[(\frac{1}{r^{12}})-(\frac{1}{r^{6}})]$$ where r is the distance between two particles. What does ... 1answer 321 views ### Simple QFT simulation - how to do it I would like to write a simple QFT simulation for a free scalar field with a cubic interaction term. However, I got stuck a bit. I will try to describe what I think I understand. I want to have a ... 2answers 143 views ### Simulation of everyday life based on standard model [closed] If I were to model the standard model, say on a super powered computer (which does not necessarily have to exist in the real world), would I get molecules, chemistry, life? I want to understand the ... 1answer 99 views ### Is the$\mu VE$ensemble possible to formulate? I have recently learned about ensembles in statistical mechanics, and I've seen multiple applications and interpretations of the EVN (microcanonical), TVN (canonical),$\mu$VT (grand canonical) and ... 1answer 57 views ### Ewald summation without repeating one particle periodically? I need to perform an Ewald summation for a Brownian Dynamics simulation. In the normal Ewald summation procedure, all particles in the simulation box are periodically repeated in the neighbouring ... 1answer 52 views ### How does phonon scattering change the distribution function? For a one-dimensional structure, we know that the modified distribution function has the following energy dependency in equilibrium: Z(\varepsilon)\,f(\varepsilon) = \dfrac{N_\text{1D}... 1answer 62 views ### Reaction-diffusion. From kinetic parameters in 3D, can we infer their equivalent in 1D? I am studying a reaction-diffusion system :$A+B ⇌_{k_{-}}^{k_{+}} C$. From experimental data I have all the kinetic parameters : diffusion coefficients$d$and reaction rates$k_+$,$k_-$. Beside I ... 1answer 153 views ### Can two distinct events occur at precisely the same moment in time? I am writing a simulation and am having difficulty resolving the order in which two distinct forces occur. The simulation will give different results if the forces are applied to the state in ... 1answer 427 views ### How do I simulate this simple quantum circuit in MATLAB I want to simulate a circuit similar to the one below in MATLAB. If you have a state matrix describing the state of 3 qubits, I understand that you could apply a CNOT matrix tensored with and identity ... 1answer 706 views ### Dynamic simulation of surface tension [closed] Is there any substantial body of work in physics on dynamically simulating effects of surface tension on liquids? The texts i found so far on fluid dynamics all seem to ignore surface tension, ... 1answer 1k views ### Rolling (without slipping) ball on a moving surface I've been looking at examples of a ball rolling without slipping down an inclined surface. What happens if the incline angle changes as the ball is rolling? More precisely I've been trying to find ... 1answer 140 views ### Mutual Interaction of$N$-Particles in a Cartesian Plane I am making a simulation of$N$-Particles in a cartesian plane and need help with understanding the basics. At anytime, in my particle system, I will have$N$number of particles. I am treating the ... 2answers 468 views ### Ideal 2D Unicycle Kinematics A particle is connected to a massive wheel by a rigid rod. The wheel can roll without slipping on a horizontal surface. The particle is free to rotate around the centre of the wheel. I believe the ... 0answers 31 views ### Is there a form of rigid body dynamics that uses unit quaternions instead of Euler angles? I’d like to know specifically about an elegant way of deriving a second derivative of an orientation quaternion from a torque and a moment of inertia matrix, if one is available. The straight forward,... 0answers 42 views ### What is the meaning of the Fourier Transform of the electric field of a well guided mode in a dielectric waveguide? I have been studying waveguiding in dielectrics for a while now; however, I cannot understand the meaning of the Fourier transformed electric field. I will first give some background information. ... 0answers 20 views ### Derivation of generation of time between two subsequent particle enters into computational domain I have problem with understanding derivation of one equation in following problem. You have 1D computational domain (it is not 1D but because it is symmetrical and we are watching only radial ... 1answer 170 views ### Missile-like trajectory calculation [closed] First of all I want to let you know that I'm not a Physicist, I am a Video Game Developer. I can simulate physical and mathematical equations and can also use some built in physics. For example I ... 0answers 25 views ### Initial conditions for a massive objects to follow a path Suppose I have a path, such as the one traced out by$r^2 = \cos(2\theta)$, and$n$objects with mass$m\$ at equidistant points on this path. What velocities should each object initially have in order ...
What would be the equation for the frequency dependent damping of harmonic oscillator? Is there something like: $$\ddot{x}+2\delta\dot{x}+\omega_0^2x = \frac{F}{m}f(t)$$ with frequency dependent ...