# Search results

1. ### Trace in statistical mechanics

Hi, im just starting a 3rd year course in Statistical Mechanics, and am a bit confused about the operator trace, Tr. I know there is a trace for quantum operators, as well as one in classical physics, but i am not sure how to calculate either, or their physical meaning. Any help would be great...
2. ### Electric fields in Matter

Hi, Suppose we have a polarized object, and wish to calculate D(r) using D(r) = epsilon E + P Do we have to account for the electric field that the polarized object creates, or is it enough to just use the electric field which created the polarization? Thanks Ray
3. ### Quantum harmonic oscillator system

Hi, I am wondering how i would go about calculating the canonical partition function for a system of N quantum harmonic oscillators. The idea of the question is that we are treating photons as oscillators with a discrete energy spectrum. I'm confused as whether to use Maxwell-Boltmann...
4. ### Bras and Kets

Hi, I am trying to show that |g> = A|f> implies <g| = <f|B where A is an operator and B is its Hermitian conjugate. I think my problem is with notation, but i have not been able to show this as yet. Thanks Ray
5. ### Fermat's Last Theorem, proof by Andrew Wiles

Hi, I am just wondering where i can find a copy of Andrew Wiles' complete proof of Fermat's Last Theorem. Thankyou Ray
6. ### Lagranian:Generalized momentum

Hi, I am wondering how to physically interpret the generalized momentum quantity derived from the Euler-Lagrange equations. For some Lagrangians is it equal to the actual momentum for the particle, however i have noticed that for a relativistic particle moving in an electromagnetic field the...
7. ### Sylow's Theorems question

Hi Why must a group of order 98 contain a subgroup of order 7? I would think that Sylow's 1st theorem implies there exists at least one Sylow-7-subgroup of order 49 and at least one Sylow-2-subgroup of order 2 (since 98=2x7x7). Thanks Ray Veldkamp
8. ### Proton detection

Hi, I'm wondering how do we detect protons, and wat sort of detectors are used for this? Thanks
9. ### Particle size

Hi i am wondering what sort of particle has a size of magnitude 10^-21 m, im thinking perhaps a string? Any help would be appreciated. Ray
10. ### Particle detection

Hi, does anyone know of something of length of order 10^-21 m? I need it for an assignment to describe the detection of something of that length Regards Ray Veldkamp
11. ### Lagrangian Action

Hi, i've just started a course in Classical Mechanics, in 3rd year undergraduate physics, and i'm a bit confused as to what exactly an ACTION is. All we've been told is that the action, S is defined as the integral from t1 to t2 of the Lagrangian with respect to time. Thanks in advance Ray...
12. ### Basic Group Theory

I lost my notes for the Intro to Group Theory part of my algebra course last year, and need to know a coulple definitions before i go back to uni this year: ORDER of a group, and CYCLIC group. Thanks Ray Veldkamp
13. ### Momentum probability Distribution

To get at a particle's postion probability distribution we take the modulus of the wave function and square it etc. , but my lecturer said next year we will learn how to get at the particle's momentum probability distribution from the wavefunction, and mentioned something about taking the...
14. ### Residual Strong Interaction

In the Residual Strong Interaction, energy and momentum are exchanged not through gluons but through exchange of quarks, for example in the soft hadronic scattering of a pi + and proton. Is the interaction mediated by a single meson or by two quarks, and if the latter doesn't this violate quark...
15. ### Pauli exclusion principle

I just finished a unit in statistical mechanics, and i have done some second year quantum mechanics and particle physics at university, however we have only been given the Pauli Exclusion principle and told that fermions obey it, but that bosons do not. My question is, does the Exclusion...
16. ### Linear Algebra HELP

Ok need help with a question that could be in tomorrow's exam: In Euclidean space R^4 equipped with Euclidean Inner Product, let W be subspace which has basis {(1,0,-1,0), (0,-1,0,1), (2,1,-3,0)}. Determine the vector in W which is closest to v=(1,0,0,-1)
17. ### Photon had a non-zero rest mass, based on measured helicity values?

Hi, got an exam tomorrow for particle physics and need a question answered concerning helicity. How would it be possible to determine if a photon had a non-zero rest mass, based on measured helicity values? Thanks Ray
18. ### Pion decay via the weak interaction

Hi, i have a particle physics exam in 2 days and am confused on pion decay via the weak interaction, namely: pi[-] ->muon + anti-muno neutrino Thankyou Ray Veldkamp