# Tag Info

## New answers tagged many-body

4

As I understand your question, and after watching your simulation, it seems that you actually only have dark matter (DM) in your simulation. An N-body code simulates DM, i.e. particles that interact only by gravitation. If you want to take it a step further, you want to include gas, i.e. particles that interact both by gravitation and by hydrodynamics. This ...

1

I've written a few small gravity simulations, and I would bet that the problem is that the particles aren't colliding. I know this doesn't answer your original question, but I think that's the answer to fixing your simulation.

4

The answer of Acid Jazz is correct in every point, in my opinion. However, I think that the problem in your simulations is not dark matter, but something more subtle. Perhaps I oversimplify here, but dark matter will behave in your model exactly like normal matter, with the exception of being dark, not visible. It is in fact exactly the case of the two ...

1

My best guess for these questions: (but I am no expert so it's a guess, right?) Should the dark matter be at all affected by the gravity of the visible particles? Yes Or should it be a one-way interaction? No, gravity should act equally on visible and dark matter. What makes the dark matter stay "in place" to preserve its "compressing" effect ...

2

Consider a $N$-dimensional vector space $V$ and let $\{\chi_1, \cdots, \chi_N\}$ be basis of $V$. Next focus attention on the anti symmetric space $(V\otimes\cdots \otimes V)_A$ where $V$ occurs $M\leq N$ times. A basis of $(V\otimes\cdots \otimes V)_A$ can be constructed out of $\{\chi_1, \cdots, \chi_N\}$ making use of the projector A: V\otimes\cdots ...

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