All Questions
Tagged with numerics or computational-physics
1,932 questions
5
votes
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answer
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Smoothed particle hydrodynamics in cosmological N-body simulations
What is the role of smoothed particle hydrodynamics (SPH) in cosmological N-body simulations like the Millenium Run (performed with Gadget-2)?
- 3,105
16
votes
5
answers
22k
views
How useful is programming in physics? [closed]
I have been wondering recently how useful programming is to a physicist. It seems fairly useful (simulations are a lot cheaper than the actual thing in many cases) in some areas (say space programs), ...
- 189
7
votes
2
answers
13k
views
Solving one dimensional Schrodinger equation with finite difference method
Consider the one-dimensional Schrodinger equation
$$-\frac{1}{2}D^2 \psi(x)+V(x)\psi(x)=E\psi(x)$$
where $D^2=\dfrac{d^2}{dx^2},V(x)=-\dfrac{1}{|x|}$.
I want to calculate the ground state energy(...
- 601
4
votes
2
answers
3k
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On numerically solving the Schrödinger equation
I just read a paper 'A pocket calculator determination of energy eigenvalues' by J Killingbeck
(1979).
Link: http://iopscience.iop.org/0305-4470/10/6/001
I have some questions about section 2.
Why $...
- 601
4
votes
3
answers
543
views
Future Computer Performance
Moore's law has succesfully predicted up to now that integrated circuit transister density doubles every two years. However, computer performance is dependent on additional factors like architecture, ...
- 5,812
17
votes
1
answer
10k
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Solving Schrödinger's equation with Crank-Nicolson method
I am trying to numerically solve Schrödinger's equation with Cayley's expansion ($\hbar=1$)
$$\psi(x,t+\Delta t)=e^{-i H\Delta t}\psi(x,t)\approx\frac{1-\frac{1}{2}i H\Delta t}{1+\frac{1}{2}i H\Delta ...
- 575
-3
votes
2
answers
150
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Standards for scientific metadata in common-use image formats? [closed]
I have a bunch of JPEG, JPEG2000 GIF and PNG files that in theory could be used for some types of science analysis if there were temporal and spatial information in them.
Years ago, I had looked into ...
- 1,678
6
votes
2
answers
3k
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how does human brain compare to a modern CPU in energy per bit?
Can someone compare the energy efficiency of human brain as a computer ? What is the energy in joules / flop ? may be some reasonable assumptions on the computational load of common tasks such as ...
- 1,772
2
votes
2
answers
351
views
Church–Turing Thesis [closed]
Can the Church–Turing Thesis be proved assuming classical mechanics, how is the proof or disproof?
Edited: I was looking for a proof of "everything computable by a device obeying CM is computable by ...
- 5,301
2
votes
0
answers
88
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Degenerated Anderson Model Simulation
I'm trying to simulate the degenerative Anderson model. So depending on an energy difference first orbital and afterwards spin magnetism occurs. First i try to solve an easier ansatz with a limitation ...
- 21
7
votes
3
answers
2k
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How to include random force in the simulation (Classical Molecular Dynamics)
I need to implement a random force in my code according to the fluctuation dissipation theorem. I have a Gaussian distribution function ready width average 0 and distribution 1 and I know I need to ...
- 711
2
votes
2
answers
746
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History of the use of the concept of phase space in engineering
Engineering textbooks constantly use the concept of 'phase space' (see e.g. http://www.cs.cmu.edu/~baraff/sigcourse/notesc.pdf). That is, they think of the state of a mechanical system as a high-...
- 727
2
votes
1
answer
2k
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Using Fourier Transforms to Solve Systems with springs of high frequency
I'm trying to numerically solve the differential equations of motion in a system with multiple springs of very high frequency. Because the solution is often a combination of rapidly-oscillating sine ...
- 727
12
votes
1
answer
3k
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What programming languages would be helpful for a physicist to know? [closed]
From the vantage point of a physicist and the kind of problems he would like a computer program to solve, what are the essential programming languages that a physicist should know.
I know C++ and I ...
21
votes
5
answers
4k
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Home-made lattice calculation?
The topic of Lattice QCD or Lattice gauge theory or even Lattice field theory is quite old now. And the main reason for the interest in the topic is the ability to calculate nonperturbative stuff on a ...
- 20.2k
7
votes
4
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675
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Supergravity calculation using computer algebra system in early days
I was having a look at the original paper on supergravity by Ferrara, Freedman and van Nieuwenhuizen available here. The abstract has an interesting line saying that
Added note: This term has now ...
- 3,632
19
votes
2
answers
5k
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How many qubits are needed for useful computation?
Seeing the news about 14 entangled states today @ Innsbruck:
I haven't found a clear guide online to how many qubits we are aiming for a first practical quantum computer,
e.g.
Factorization,
Search ...
- 319
8
votes
1
answer
574
views
How to simulate a crashing wave? [closed]
I'd like to create a very rough animation of a wave crashing on a beach. I'm guessing it would have to be a particle simulator, where you code in the forces between the particles and then integrate ...
- 507
3
votes
1
answer
2k
views
live Kp index data
I need to create an online service displaying latest Kp index.
Where I can take the data?
The data should be in machine-readable format, i.e. text files, XML, or CGI gateways, for instance. No ...
- 133
3
votes
3
answers
445
views
Mixed conductive and convective heat transfer
I want to make a finite element analysis of a cold airflow through warmer pipes. In particular I want to see how the pipes cool down and the air heats up, as it travels through the pipes. Wich are the ...
- 381
7
votes
2
answers
3k
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Physics of simple collisions
I'm building a physics simulator for a graphics course, and so far I have it implementing gravitational and Coulomb forces. I want to add collisions next, but I'm not exactly sure how to go about ...
- 151
7
votes
4
answers
1k
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Dirac equation on general geometries?
I have a numerical method for computing solutions to the Dirac equation for a spin 1/2 particle constrained to an arbitrary surface and am interested in finding applications where the configuration ...
- 235
14
votes
1
answer
3k
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What is the status of applying numerical analysis to QM/QFT problems [closed]
This is something I don't ever seem to hear about, except regarding QCD ("lattice QCD"). What about QED? Is numerical integration always inferior to hand-calculating Feynman diagrams in perturbation ...
- 7,488
12
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5
answers
2k
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Basic mechanics problems, unsolvable by brute-force numerical integration
I'm looking for simple problems in theoretical mechanics that are impossible or unreasonably difficult to solve by means of "brute-force" numerical integration of Newton or Euler-lagrange equations.
...
14
votes
7
answers
2k
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Binary Black Hole Solution of General Relativity?
This is rather a technical question for experts in General Relativity. An accessible link would be an accepable answer, although any additional discussion is welcome.
GR has well known solutions ...
- 4,763
20
votes
4
answers
7k
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How efficient is a desktop computer?
As I understand it (and admittedly it's a weak grasp), a computer processes information irreversibly (AND gates, for example), and therefore has some minimum entropy increase associated with its ...
- 53.6k
5
votes
3
answers
325
views
Simulate a physical impact of objects made of finite, small elements
I want to simulate an impact between two bodies according to gravity, and eventually considering other forces to stick matter together. I'd like to use python to do this, but I am open to alternatives....
- 3,950
3
votes
1
answer
318
views
Using Relaxation Method to Model Negative Dielectrics in an electric field?
How can you use the relaxation method to model negative dielectrics?
The relaxation method is usually used to model electrostatics problems but negative dielectrics are only see in dynamic systems.
...
- 210
12
votes
6
answers
22k
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How is computer science and physics related? [closed]
Not sure if this is a 'real' question, but what is the relationship between physics and computer science? A lot of physicists are also computer scientists and vice versa. My professor has a PhD in ...
- 1,158
18
votes
8
answers
6k
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Software for physics calculations [closed]
What is some good free software for doing physics calculations?
I'm mainly interested in symbolic computation (something like Mathematica, but free).
5
votes
1
answer
813
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Mathematica to help for an Hamiltonian problem
I have an Hamiltonian problem whose 2D phase space exhibit islands of stability (elliptic fixed points).
I can calculate the area of these islands in some cases, but for other cases I would like to ...
- 4,838
5
votes
4
answers
1k
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