For the given Hamiltonian, $H=\sum_{i}a^{\dagger}_{i}a_{i}$, how one could evaluate the green's function using path integral approach? Particularly how one could do that in brute force method similar to the one that of simple harmonic oscillator green's function evaluated in phase space using p...

I'm trying to parse a delimited string that has some empty parameters. Example: "|One|two|three||octopus|garbagecan||cartwheel||||" Basically I need to be able to pull out any segment by id, and if the segment is empty return null. strtok doesn't handle the empty fields, and it looks like ...

First, valid points are made in both Down-voting questions: Please state your rationale and Snobs and down-voters. That is, we need down votes because they discourage poor posts. And it is helpful to have a good attitude and thick skin when you get a down vote. That said, we need to not overdo ...

First, valid points are made in both Down-voting questions: Please state your rationale and Snobs and down-voters. That is, we need down votes because they discourage poor posts. And it is helpful to have a good attitude and thick skin when you get a down vote. That said, we need to not overdo ...

It occurred to me today that I don't know what a good approach is for providing hints to homework-like questions. I cannot find any clear policy on how this should work. The example that brought it to my attention is this question. My initial reaction was to comment with a question to help poi...

Recently I was eating a yellow rice for lunch in a restaurant with only yellow lights. But the rice looked white! I was intrigued by this because I always thought it should look yellow since the yellow pigment reflects only yellow light, but the rice looked really, really white. Why is that? I th...

I use irony rather often, but in written texts such as email I'm often afraid that it might be misinterpreted by the reader. Therefore I'd like to use an emoticon to make the irony explicit, but I'm not sure which one is most often used for this purpose. Which one would be most suited?