# Search results

1. ### What do you do to remotivate yourself once you hit rockbottom

Changed colleges!
2. ### What do you do to remotivate yourself once you hit rockbottom

I was a student that people believed wouldn't even manage to complete my bachelors. I was going that bad. I wasted a year! But as Topher pointed out, you might be in the wrong kind of courses. I was too. It wasn't much of my fault. In the last 3 years, I have been at the top of like 80% of all...
3. ### Sidney Coleman Lectures Free on the Net

Thanks. I figured that on my own soon after I made that post in march.
4. ### Sidney Coleman Lectures Free on the Net

I suppose these videos can't be downloaded since they are streaming. Anyone know how to download them?
5. ### Schools Applying to grad school without research exp?

I think I can understand your situation well because I'm in a similar situation. I'm also thinking of doing research and then applying next fall again. I'm applying this time too, but I know I have a dim chance.
6. ### 2-D Waves: Relation of power with radius

That is very helpful. I never knew one could think of the relationship between power and raidus that way.
7. ### 2-D Waves: Relation of power with radius

Thank you. Correct me if I am wrong: Power falls off as 1/r^2 in 3-D 1/r in 2-D Constant w.r.t. 'r' in 1-D? You've been very helpful. I've been confused about this question for a while now!
8. ### Improving at mathematics and physics?

You know I could do mutliplications like 343*434 in just seconds when I was 10-11 but that doesn't make me a genius. I started calculus first at the age of 17 and to this day I have trouble doing very simple integrals and differentiations. Reason? I never 'attacked' calculus the way I did simple...
9. ### 2-D Waves: Relation of power with radius

As I understand, power is directly propotional to amplitude squared for all waves. In the 2-D case, how will power depend on 'r'? For plane waves, the wavefunction is exp(ik.r) and multiplying it with its complex conjugate gives a constant amplitude and thus a constant power (I think). But...
10. ### Schools Applying to Grad School without Research Experience

There is only one faculty member, in my university, whose research area is theoretical high energy physics. How much he helps students in research can be seen from the statistics - reportedly he hasn't supervised a single PhD student in his 30+ years as a professor. I asked a few professors...
11. ### Schools Applying to Grad School without Research Experience

Yes, I have talked to a couple of them. They didn't have any research experience, but they didn't manage to get into very competitive schools! I didn't think about it before. I'll ask my professors to mention in their recommendation letter to clearly mention that the university doesn't have...
12. ### Schools Applying to Grad School without Research Experience

I have read some statements of purpose from people who got in some of the most selected gradschools. The way they show they are interested in research is by talking about the research experience they've had. I just wonder how convincing one can be without research experience. Thanks for your...
13. ### Schools Grad School/GRE

This time it's available only in October, November and April. No December GRE Subject this time around!
14. ### Schools Applying to Grad School without Research Experience

That's what I'm afraid of. I was wondering if there's any way I could show off my eagerness for research. Like, for example, I have given a seminar in my department, nothing original, just a little technical seminar on Quantum Mechanics discussing some common misconceptions, and ending with a...
15. ### Schools Grad School/GRE

A very good website that has profiles of a lot of US gradschools with physics and astronomy programs is http://www.gradschoolshopper.com/" [Broken] It has very useful information, average GRE score requirements, faculty, etc. The only drawback is that it's not very up to date. It's based on...
16. ### Schools Applying to Grad School without Research Experience

I'm considering grad school in the US. I don't think US universities require research experience, but most people who get in good universities have some kind of research background. I will look at a few Canadian university websites. Thanks. ps: One of my Pakistani-Canadian friends also had...
17. ### Schools Applying to Grad School without Research Experience

Hi, I'm going to apply for grad school this fall. I'm an international student from Pakistan. Although I don't have extraordinary credentials, but I think I satisfy the minimum - top 10% of my class. I'm also confident of scoring high on GRE Physics as some trials have went unexpectedly well...
18. ### A good quantum mechanics book for the self-learner?

For a padagogic intro, use Griffiths' book. For problem solving, try Zettili's QM book. Also Tamvakis' solved problems book on QM is excellent. I personally like Liboff, except the 14th chapter (scattering)!
19. ### Interactive fields in QFT - the φ^3 example

It's discussed in many books. Take a look at this draft of a QFT book by Srednicki: www.physics.ucsb.edu/~mark/qft.html Sterman's QFT book also discusses phi-3 theory, so does Muta's QCD book.
20. ### Trigonal lattice with each angle equal to 120degree

1. What happens when the angles between the three sides of a trigonal reach 120degrees? I know that at 90degrees, it becomes a simple cubic. At 109degrees, it becomes a body centered cubic. At 60 degrees, it becomes a face centered cubic. What about 120degrees? I think that perhaps it should...
21. ### Does negative mass exists?

What about the 'negative energy' solutions of Dirac's equation? Doesn't negative energy suggest negative mass? In my QM course, my Prof. taught us repeatedly energy can't be negative. But then I was hearing this discussion about how Dirac proposed the existence of positrons and I was confused...
22. ### Acceleration Tensor - Rotating Frame

If a coordinate system is rotating, that is time 't' is not independent, then does the acceleration transform as rank 1 tensor? I thought that it wouldn't because when time is changing, so acceleration will change in a more complicated way than a rank 1 tensor. Perhaps as a rank 2 tensor...
23. ### Differential Equations

A solution to a DE means that the value of 'x' or whatever the variable is, satisfies the equation. There can be infinitely many solutions to a DE! You should better consult your textbook. Or read Schaum's outline of DEs. I don't think anyone will solve these Qs here for you. We need to know...
24. ### Vector Potential: How to Find it?

Vector V=x^2i+3xz^2j-2xzk The divergence of this vector is zero. So it can be expressed as the curl of a vector. I have to find that vector, which is also called the vector potential. But I don't know how to find it. When I have to find the scalar potential, then it is easier to equate...
25. ### Crystal physics problem

In simple cubic's case, it is quite simple. For BCC: Consider the body diagonal. It's length is aXsqrt3 (Pythagorus Theorem!). For FCC: Consider the face diagonal. It's length is aXsqrt2 (Pythagorus again!).
26. ### Transformation Matrix Problem

I don't know if this is the right section, but this problem is in my electromagnetism course (Griffiths text). This is problem 1.9 of Griffiths (3rd edition) text: Find the transformation matrix R that describes a rotation by 120 degrees about an axis from the origin through the point...
27. ### Crystal Planes, Miller Indices: Cubic Lattice

Thanks a lot for that. I am actually quite new to this concept of crystal planes and miller indices, that's why I have trouble not only for solving problems but also to understand crystal structures. I solved the Q that was troubling me, and hopefully I'll be able to go through my exercise...
28. ### Crystal Planes, Miller Indices: Cubic Lattice

Just when I thought I understood the concept of planes and miller indices, I got stuck on a 'test your understanding' Q in my book. I can't understand that there can be two or more (110) planes in a crystal lattice? I thought there can be only one such plane. The question asks me to find the...
29. ### Are the Feynman Lectures on Physics books good?

I have read a few chapters randomly and I think what makes this book such a favorite with students is it's unusual approach to topics. I often find something in this book which I haven't seen elsewhere. Feynman really makes you love physics but his book is not a standard textbook because it...
30. ### The Best Textbooks Thread

I started studying a book on mutlivariable calculus/linear algebra a few days back and I have already started to like it a lot: Vector Calculus, Linear Algebra and Differential Forms: A Unified Approach by John Hubbard and Barbara Hubbard I especially enjoy reading the margin notes...