Recent content by bardeen

Sorry I don't think I'm getting it. What would the expression for the envelope be?

But then, is there a group velocity to the whole thing? The first two terms you wrote have a group velocity Δω/Δk, and the last one is just a plane wave. But what is the group velocity of all three terms put together?

You get two terms of the same form as in the usual case. So, you get something like: envelope1*(sine wave) + envelope2*(cosine wave) Is the group velocity still delta omega/ delta k ? That's what my instinct told me but I somehow feel it's not right...

Hi all, I understand the concept of group velocity when applied to superimposed sine waves of the same amplitude, and even when applied to wave packets (in which case you get the well-known expression ∂ω/∂k). My question is what happens when you add two sine waves of different amplitudes? So...

And I have never understood why physics departments do so much advertising for physics. Why do they want more and more physics PhDs if there aren't enough appropriate jobs for them? I don't think the field would die if not for their advertising, since there will always be people that go into...

Thanks all! I'm more motivated to carry on! One more thing... how does one date while doing a PhD? It's really tough since it's almost all guys in physics grad school and it's hard to find the time to go out and meet girls. Any suggestions? I'm looking for a wife-material type of girl :)

(or tell me whatever your opinion is) I am in my second summer as a graduate student and have reached a point where I am questioning all my decisions. I used to think that what was most important in my professional life was that I be doing something I loved (and that it at least payed...

Hello all, Suppose I want to find all publications by X author. What is the best way to do this? I am overwhelmed by all the options out there. Also, how does it all work? What I mean by this is, when you publish something, say in Phys. Rev., does Web of Knowledge and Arxiv get automatically...

Thank you, that was very helpful. When you have an up electron and a down electron, the total spin can either be 1 or 0. I'm having trouble understanding this. If one is pointing up and the other pointing down, why isn't the total spin just 0 everytime?

This is a pretty basic question I believe. When you describe the state of a single particle, let's say its spin state, it can be in a superposition of different states (like up and down). When you do a measurement of its spin you'll either get up or down, since its spin state will collapse into...

Thank you guys, that helped :)

That sounds interesting, thanks for raising my hopes. Can you send me this person's webpage?

Hello all, I am a second year physics grad student in the US. I'm writing this in the hope that someone who has gone through grad school can help, although I'll gladly take opinions from other people :). Ever since I came here for graduate school (I did my undergraduate education outside the...

How do you feel is the atmosphere inside the graduate student community? How is living there, in general? Are there lots of things to do? Are you going to grad school yourself?

1. You don't go into this for the money. Although I don't like people that emphasise this TOO much. I think there's nothing wrong in informing yourself what you're in for in the economic side. 2. Salaries vary a lot. A noble prize winner in my department has a salary of about 560K a year (his...