# Tag Info

14

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. Different approaches into solving this equations gave birth to different numerical methods, and some methods are more efficient for solving specific problems, ...

10

Goptical GNU-Optical Description Goptical is a C++ optical design and simulation library. Goptical is free software and is part of the GNU project. It provides model classes for optical components, surfaces and materials. It enables building optical systems by creating and placing various optical components in a 3d space and simulates light propagation ...

10

There are, of course, a lot of codes floating around. Which of them you should choose, depends on what you want to calculate exactly. Here I mention four possibilities: 1) CALHEP - this package takes you from a given Lagrangian through its Feynmann rules to the calculation of cross sections. 2) xloops - this package calculates the 1-PI Feynman diagrams ...

10

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-Oppenheimer approximations, perturbation theory, and angular momentum theory. A course specifically in atomic and molecular physics would also help. As you say, and as ...

9

I just discovered: opticalraytracer From the manual: OpticalRayTracer is a free (GPL) cross-platform application that analyzes systems of lenses and mirrors. It uses optical principles and a virtual optical bench to predict the behavior of many kinds of ordinary and exotic lens types as well as flat and curved mirrors. OpticalRayTracer ...

9

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 question with exactly what it is you're doing and how), then your code is wrong. The reason is that your results don't obey the maximum principle: a harmonic ...

8

Just for completeness, I'll leave this here: It's always possible to compose your illustrations in raw postscript! Postscript is itself a Forth-like programming language. It's particularly useful for illustrations that lend themselves to being generated procedurally. If postscript itself is too low-level, one can often write a script in some other ...

8

For record: It looks like this topic really interests some people: http://markmail.org/message/nic7xrgf5uzed5c4 Newport was obviously thinking in the same direction: They offer an option to use SketchUp and provide 3D models of their mechanics and lenses—at least they used to, since this page does not exist anymore and the picture above was kindly sent to ...

8

This probably isn't exactly what you're looking for, but if you're looking for the time-independent bound states of a system, the Fourier grid Hamiltonian method may be applicable. Here is an application of it to the following strange-looking potential well: Here are a few low-energy bound states: And here are some of the high-energy states: I used a ...

8

There are only two open source GR/tensor packages that I am aware of, Cadabra (coordinate-free) and Maxima/xwMaxima (coordinate based, ctensor, itensor and atensor packages)

7

For drawing Feynman diagrams with SVG, I have developed jQuery.Feyn to make it easier (see the screenshot below).

7

Newton's shell theorem relies on Gauss's law, which in $d$ spatial dimensions implies a $r^{1-d}$ force law. Since $d=2$, the force should fall off as $1/r$. This explains why OP's first plot (with an $1/r^2$ code) fails to produce a vanishing interior force, while OP's second plot (with an $1/r$ code) produces a vanishing interior force. (Btw, the ...

5

You might find something on this page, if not, on the site somewhere. I have not checked it out tonight, but I am sure I have seen programs there, in the past. http://www.realclimate.org/index.php/data-sources/ Clive Ballard

5

The Hartree potential is typically calculated not through the integral you're giving, but by solving Poisson's equation. Look here or there for details about this calculation applied to DFT, and here for what I found to be a good lower-level introduction to Poisson solvers in general. Good luck for your quest, it's really a nontrivial thing to do! As an ...

5

This gentleman wrote 2 games that involve quantum mechanics, not sure if its exactly what you are looking for. http://www.engr.newpaltz.edu/~biswast/

5

There is indeed a hybrid "quantum computer game" called Quantum moves (playable on Windows, Mac, Linux, Andriod, iOS) which is the first gamified citizen science project of Science at home. Quantum moves pursues two different objectives. On the one hand, it is an attempt to popularization of quantum physics, but it is at the same time a research programme ...

5

There are the EMS, an add-in to Solidowrks, so you can simulate in 3D: (payed). Others: Amperes Quickfield MagNet Open source: MaxFEM

5

The closest program to the description is Phun: http://phun.en.softonic.com/ Download it, it's a lot of fun. Oh, I see, you want 3D immediately. Ambitious enough so that I won't erase my answer. Update, May 2012. You may try to download trial of Wolfram System Modeler, http://www.wolfram.com/system-modeler/

5

Is there a complete physics simulator that I can use to do general simulations for learning purposes? Any Turing complete programming language. Some assembly required. We often say that all models are wrong, so whatever problem you desire to simulate is working on some level of abstraction of more fundamental physical laws. These are generally problem-...

5

A thought experiment: after N steps, each of which create a change in angle $\Delta \theta$, we should end up with a normal distribution of angles with a standard deviation of $\frac{\sigma}{\sqrt{N}}$. When you change the step length, you therefore need to scale the standard deviation by the square root of that change, so that after moving the same distance ...

5

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 here. I'd start with reading the pdf there, then look at the code—it shouldn't be too hard to follow. There are also several Mathematica examples here, and ...

5

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 $t=0$, vibrates for time $\tau$, and then turns off. As an equation, that looks like this: $$y(t) = \sin(2\pi f t)\, \Theta\left(\tau-t\right)\, \Theta(t),$$ where $\Theta(... 5 Your sampling rate is 48k at 55Hz, so each period is 872.73 samples. The size of your FFT is 65536. It fits 75.093 period of the signals. The algorithm takes 75 periods to plot the chart. This leaves 0.093 periods between consequitive FFT transforms. 0.093 periods at 55Hz correaponds to a frequency of 5.1Hz that matches the ghost frequency that you see ... 5 Your iterations are converging to a solution of Laplace's equation,$\nabla^2T(x,y)=0$, with your boundary conditions. This equation can be solved exactly in a rectangular area, with$T\$ being arbitrary specified functions along the borders. The solution technique produces an infinite series, as shown here: http://ramanujan.math.trinity.edu/rdaileda/teach/...

4

I too use Mathematica for figures and found it wasn't a great leap from there to using it for drawings. You can draw 2D or 3D primitives pretty easily: Rectangle[{xmin, ymin}, {xmax, ymax}] and, like python/matplotlib, being able to parameterise everything allows you to redraw an image for multiple scenarios (or Animate or Manipulate it). For me the most ...

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