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3
votes
2answers
56 views

Can I identify phase (solid, liquid, gas) just from a snapshot of molecule positions?

Suppose I have a simulation of a bunch of nitrogen molecules (N_2). Just by looking at the positions of a bunch of the molecules in a volume of space, how can I tell whether the picture is showing a ...
2
votes
2answers
135 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 ...
0
votes
3answers
52 views

Multi-Force Lift

Background: I am creating a 3D game. A ship has 3 thrusters that apply force up (Z+) to counteract the force of gravity (Z-). I am trying to figure out how much thrust to apply to each thruster to ...
-1
votes
2answers
83 views

What is the output of a simulation of quantum particles? [closed]

When physicists simulate a quantum system, what is the output of such computation? Is it the probability wave function of the system? What if the system consists of enough particles to be considered ...
2
votes
0answers
24 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 ...
0
votes
2answers
169 views

Must-know topics for Computational Fluid Dynamics (CFD)

My undergrad major was Electrical Engineering. My MS thesis is related to simulation of hydrogen movement in a complex geometry. I did take a course on Fluid Dynamics but I have to say it wasn't one ...
2
votes
0answers
53 views

Simulation of oscillator with frequency dependent damping

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 ...
0
votes
0answers
17 views

Setting up initial configuration of a Micelle - Molecular Dynamics

I have just started learning Molecular Dynamics using dl_poly_classic and analysing trajectory using nMOLDYN. Our primary aim is to do neutron scattering, but however we do Molecular Dynamics to ...
2
votes
1answer
175 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. ...
0
votes
2answers
136 views

How Much Computing Power would be Required to Fully Simulate a Cubic Meter? [closed]

Imagine you want to simulate a cubic meter down to the particle. By following the Standard Model and other basic physical equations, how much computing power would be required to do this, in say, a ...
3
votes
1answer
57 views

Precise definition of Jet Energy Scale and Jet Energy Resolution

I've been struggling to get the precise meaning of these two quantities, is it correct to say that the first one is only related to Montecarlo simulations? I can't seem to find a pedagogical ...
0
votes
0answers
92 views

Path Integral Simulation

I am trying to do a simulation with path integrals. I previously simulated with a step potential by time evolving the eigenvectors of the Hamiltonian. See code and video. Notice is is a bit weird, ...
7
votes
1answer
244 views

Converting between $\frac{d \sigma}{d t}$ and $\frac{d \sigma}{d \Omega}$

I'm performing some simulation where I require the integration of a cross section of the form $$\sigma = \int_{-s}^{0}dt \frac{1}{(t-\mu^2)^2} f(\theta,\phi)$$ where $s$ and $t$ are the usual ...
0
votes
0answers
73 views

Position and Tension of Kite/Balloon Tether in Presence of Wind

I wish to solve for the position of a kytoon's (hybrid kite and balloon, with both aerostatic and aerodynamic lift as well as non-negligible drag) tether given the forces present on the kytoon and ...
0
votes
1answer
47 views

How does Parallel tempering work for optimisation procedures?

Markov Chain Monte Carlo procedures can be used in global optimisation procedures. Parallel tempering is a particular type of stochastic sampling, but how does it work?
0
votes
1answer
72 views

Clarification of the physics involved of an orbiting body in a circular orbit

I am writing a physics simulation program to simulate a body orbiting a planet but I am a little confused about the physics involved and would like some clarification. To simulate gravity I am using ...
2
votes
1answer
93 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 ...
2
votes
0answers
59 views

How to let Pythia to output the complete event record in LHEF or StDHep format?

I am currently using Pythia 6.4 to simulate some processes (I do not have the intention to upgrade to 8). Now, I need Pythia to output its event record in the format of LHEF or StDHeP. I accidently ...
-3
votes
2answers
141 views

The Simulation Hypothesis As A Theory Of Everything [closed]

I have long found the Simulation Hypothesis to be better-able to answer questions that I have regarding the universe than the string theory and the quantum field theory. What I believe is that the ...
0
votes
1answer
54 views

Evolution of dark matter and gas temperature

So I have recently watched a simulation of dark matter density and gas temperature evolution in a universe. However I couldn't find description of under what assumptions it was was made and what it is ...
1
vote
0answers
172 views

3D Simulation Software

I need a software capable of simulating the physics of a car going off a ramp. This is a stunt that I will be attempting and looks like the following: A car, going off a curved ramp, doing a barrel ...
3
votes
1answer
166 views

Critical temperature and lattice size with the Wolff algorithm for 2d Ising model

When I run my implementation of the Wolff algorithm on the square Ising model at the theoretical critical temperature I get subcritical behaviour. The lattice primarily just oscillates between mostly ...
0
votes
2answers
91 views

Simulation of a simple robot [closed]

I'm a programmer and I'm working on a simple robot simulator. Of course, the most important part of this simulator, is the physical simulation of the robot. Unfortunately, I have a little knowledge ...
0
votes
0answers
15 views

Optics Simulation Software for Airy Beam Generation [duplicate]

I have been trying to simulate the generation of Airy Beams using a simple two-cylindrical lens setup as shown by Papazoglou et al. http://journals.aps.org/pra/abstract/10.1103/PhysRevA.81.061807 I ...
4
votes
4answers
290 views

How can I add dark matter to my $N$-body simulation?

I've written a simple non-scientific N-body simulation for fun: http://magwo.github.io/fullofstars/ I expected to create something looking like spinning galaxies (there are two invisible very heavy ...
2
votes
1answer
50 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 ...
0
votes
1answer
38 views

What velocity do I need to get the moons orbit perfectly aligned with the earths center [closed]

I have a simulation for universal gravity with two objects. How can I calculate the velocity or instantaneous force I would need to apply to object 2 (the moon) to get it to orbit so that the origin ...
1
vote
0answers
90 views

Do I need a particle to simulate a particle? [closed]

Edit TL/DR Is an assumption of the theory that the universe is a simulation that the simulating universe is fundamentally more complex than our own? The Long Version As a programmer, I find the ...
0
votes
0answers
24 views

Can we use Variational Monte Carlo for degenerate cases?

Consider Simple Example of Bose-Hubbard model $$H=-J\sum\limits_{<i,j>}b_i^{\dagger}b_j+h.c.+\frac{U}{2}\sum\limits_{i}n_i(n_i-1) . \tag{1}$$ We can solve this Hamiltonian by Variational ...
2
votes
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: \begin{equation} Z(\varepsilon)\,f(\varepsilon) = ...
3
votes
2answers
203 views

Why is my Lyapunov exponent similar for single and double pendulum?

This is my first question here on stackexchange. I hope that I can be understood. If not, tell me and I will reformulate and fill in with details. I have simulated a single pendulum and a double ...
1
vote
1answer
97 views

Difference between Enzo & Gadget astronomy simulation codes

Enzo and Gadget are simulation codes used in astronomy. What are the largest differences between them both in terms of physics they simulate and in their implementations?
3
votes
2answers
106 views

Why is my two body model not working? [closed]

I have created a simple 1 Dimensional two body particle model in C++. In the model, particle 1 starts at position (0,0) and particle 2 starts at position (1,0). The particles are accelerated towards ...
2
votes
1answer
95 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 ...
0
votes
0answers
45 views

How to simulate “inside-out” geometries of a structure?

How can I simulate the structural deformation of a physical material to find all possible "stable" inside out forms? For example, some dome shaped rubber caps can be pushed inside out, like the ...
0
votes
1answer
70 views

How do I evaluate the angular momentum of the wave function?

I'm working with Bose-Einstein condensates and running a 2D single component Gross-Pitaevskii equation solver for the simulations in MATLAB. The way it works is that it numerically solves the GP ...
0
votes
1answer
483 views

How to calculate impulse force on collision?

I've made a program which is supposed to simulate free fall of a ball on a ground. For collision with the ground I relied on calculating the impulse force with the answer in this Phys.SE question ...
0
votes
0answers
68 views

How to properly implement Huygen's integral?

I'm really confused by what's happening ... I'm trying to propagate a beam some distance and compare initial and final intensities. Lets say the initial electric field is just cos(200x). I then used ...
1
vote
2answers
297 views

Incompressible Navier-Stokes pressure solve in simulations

I am a complete newcomer when it comes to fluid simulations. I'm currently working through some tutorials to understand the idea of of the discretized Navier-Stokes equations for numerical ...
-1
votes
2answers
69 views

What are the consequences of a non-computable universe?

I have seen that is is debated if the universe is digital, computable or non-computable. what specific consequence could this have in the format of the laws of physics? Or would that mean that we will ...
0
votes
0answers
64 views

Projectile motion with wind

I am trying to simulate a projectile motion with wind and gravity. (I'm a programmer so excuse my knowledge on the subject) I want to know launch rotation of a person in 3d to throw a ball forward ...
0
votes
0answers
68 views

Acoustic sound box simulator

I'm looking for a simulator (2 or 3 dimensional + time) of an acoustic box. I'm trying to see where the high/low pressure areas would be depending on where I tap the box on the outside. PS. Not sure ...
6
votes
5answers
444 views

Resolving General relativity and Newtonian mechanics to a computer [closed]

I know this is considered an old subject long ridiculed by many as the folly of layman. But I work in the field of computer simulation, specifically in producing fully functional 3D interactive ...
0
votes
0answers
41 views

What discrete form of the wave equation do you need to use to make a wave simulation?

I'm working my way through these blog posts about the wave equation. All has made sense up until now. The wave equation is $$ \frac{\partial^2h}{\partial t^2} = c^2 \frac{\partial^2h}{\partial x^2} ...
1
vote
1answer
87 views

Meaning of imaginary eigenvalues in advection equation

I'm reading the book Fluid Simulation for Computer Graphics (Amazon link), and stumped by the following sentence in Chapter 3: what's happening is that the eigenvalues of the Jacobian generated ...
3
votes
1answer
44 views

Ocean surface mean current flow meaning

I tried to simulate the trajectory of an drifting object in the oceans by using the data of the OSCAR project http://www.oscar.noaa.gov/. The dataset actually used consist of grid sampled mean 2d ...
0
votes
0answers
64 views

Explicit Ewald equations for dipole-dipole interaction in a simulation

I'm starting to work with spin ice simulations and I found that it is usual to use the Ewald method for the long-range interactions computation (dipole-dipole in this case). Although I've been reading ...
0
votes
0answers
77 views

Computer simulation/visualization of a ray of light passing near a massive object

I'd like to write a computer program that simulates and visualizes the trajectory of a ray of light as it passes near a massive object (e.g., neutron star). In other words, I'd like to model light ...
0
votes
1answer
161 views

Is the dimension “number of particles” a fundamental, or derived dimension (based on mass), or does it depend on the context, or is it dimensionless?

I consider "fundamental quantities" to be those that have dimensions that are are like length, mass, time, temperature, and so on. "Derived quantities" have dimensions that can be written in terms of ...
2
votes
0answers
40 views

How to find the maximum torque to apply to a robot joint to have realistic movement? [closed]

I am a computer science student. I am trying to simulate a locomotion of a legged robot. The weight and dimensions of the robot: A rectangular torso has 1 Kg, (0.15m*0.3m*0.03m) (width * length * ...