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Sep 15, 2021 at 17:16 comment added Willie Wong Aren't there infinitely many rhombi with unit side length? The solution when $N = 3$ is not unique, even if you quotient out by the symmetry swapping the particles. (Solution space should be $N-2$ dimensional, if I didn't make a mistake.) // I'd love to see an animation...
Sep 15, 2021 at 16:49 comment added Leo Moos @Sinusx You're right, thanks for pointing this out; I corrected the question.
Sep 15, 2021 at 16:49 history edited Leo Moos CC BY-SA 4.0
corrected minus sign error
Sep 15, 2021 at 15:24 comment added Viktor B Wouldn't the 'conservation of momentum' equivalent be $v_1 = \sum_{i} v_{1i} $? For instance if $N=1$, then by your equation the new particle starts moving in the opposite direction.
Sep 13, 2021 at 14:36 comment added Leo Moos @CarloBeenakker They'd be picked uniformly at random from among the intersection $\{ \sum x_i = -v_1 \} \cap (\mathbf{S}^1)^N$.
Sep 13, 2021 at 14:22 comment added Carlo Beenakker I'm confused; how would you implement the constraint $x_1+\cdots +x_N=-v_1$ if you pick them uniformly at random from the unit circle? Supposse the first $N-1$ you pick happen to be nearly aligned, then the velocity of the $N$-th particle might have to be much larger than unity to achieve the desired sum.
Sep 13, 2021 at 13:47 history edited Leo Moos CC BY-SA 4.0
added paragraph to clarify and explain distribution of momenta
Sep 13, 2021 at 13:40 comment added Leo Moos @CarloBeenakker Good point, I forgot to mention that the particles would move at unit speed, meaning $v_{11},\dots,v_{1N} \in \mathbf{S}^1$. That being understood, the momenta would be picked from $\{ (x_1,\dots,x_N) \in \mathbf{S}^{1} \times \cdots \times \mathbf{S}^1 \mid x_1 + \cdots + x_N = - v_1 \}$. As the product $(\mathbf{S}^1)^N$ is compact, I guess they could be picked uniformly at random; would that make sense to you?
Sep 13, 2021 at 13:32 comment added Carlo Beenakker with what distribution would you choose the decay momenta? they are obviously not i.i.d. ...
Sep 13, 2021 at 13:18 history asked Leo Moos CC BY-SA 4.0