Why was my thread deleted?

[Geigercounter]

First of all, I don't know where to put this.

I had a thread in the advanced physics homework help (https://www.physicsforums.com/threa...dark-matter-numerically.1052335/#post-6883072) but it just vanished overnight. I never got a notification or something.

What happened here?

 

[berkeman]

First of all, I don't know where to put this.

I had a thread in the advanced physics homework help (https://www.physicsforums.com/threa...dark-matter-numerically.1052335/#post-6883072) but it just vanished overnight. I never got a notification or something.

What happened here?

It looks like it got hard deleted somehow. Is it related to this reply of yours?

I'm stuggling with a similar problem! Any updates on this thread @JD_PM? or @phyzguy? I've also posted my version of this question on ths forum.

I already found that the above method won't work, because this supposes an analytical solution can be found in Matlab. We'll need to implement a numerical solution, and we'll have to use the ode45 function or similar in Matlab.

 

[Greg Bernhardt]

When did you post it?

 

[mfb]

Based on the post id it must have been May 10 between 3:32 and 3:34 pm UTC.

 

[Geigercounter]

It looks like it got hard deleted somehow. Is it related to this reply of yours?

Yes it is! It was similar to that question but I had some extended questions and gave some more details than that thread.

 

[berkeman]

It looks like you've been able to successfully repost:

Homework Statement: I want to compute the following path integral
$$Z[w] = \frac{1}{(2\pi)^{n/2}}\int d^n x \: \prod_{i=1}^{n}d\overline{\theta}_id\theta \: \exp{\left(-\overline{\theta}_i \partial_j w_i(x)\theta_j -\frac{1}{2}w_i(x)w_i(x)\right)}.$$ Here $w_i(x)$ are functions of the $n$ real variables $x_i$ and $\theta_i$ and $\overline{\theta}_i$ are $n$ independent Grassmann variables.
Relevant Equations: See below.

The first step seems easy: computation of the $\theta$ and $\overline{\theta}$ integrals give
$$Z[w] = \frac{1}{(2\pi)^{n/2}}\int d^n x \: \det(\partial_j w_i(x)) \exp{\left(-\frac{1}{2}w_i(x)w_i(x)\right)}.$$

From here, I tried using that $$\det(\partial_j w_i (x)) = \det\left(\partial_j w_i \left(\frac{d}{db}\right)\right) \exp\left(b_i x_i\right)\bigg\vert_{b=0}.$$ But I don't seem to be able to apply this step.

Other ideas I had included writing out the determinant as $$det(\partial_j w_i(x)) = \frac{1}{n!}\varepsilon_{i_1...i_n}\varepsilon_{j_1...j_n} \partial_{j_1} w_{i_1}(x) ... \partial_{j_n} w_{i_n}(x)$$ to then use some kind of partial integration.
Another, similar, idea was to use the fact that $$\det = \exp(\text{Tr} \ln) $$

 

[Geigercounter]

@berkeman This is a different post... But I'm looking for an answer there too! If you could maybe have a look :)

 

[Greg Bernhardt]

All I can think of is that yesterday I did prune some soft deleted threads, but I made sure they were older than 180 days ago. Really weird.

 

[Tom.G]

Really weird.

With the several "oops" incidents and backward non-compatibility incidents recently, would it be appropriate to slow down on "new-and-improved" implementations?

 

[berkeman]

There's more to the OP's account than you can see. Probably not their fault, but probably why their post came the attention of the AI that protects us.

 

[Tom.G]

OK, thanks for the reply, but...

What! The Robots have invaded here too?

 

[julian]

Your thread has been terminated.