Stat mech Definition and 63 Threads

  1. E

    Does Tension Apply in One-Dimensional Particle Systems?

    Homework Statement My stat mech book does a problem where it calculate this quantity F for a system of particles restricted to move in one dimensions using the equation F = \frac{\partial A}{\partial L} where A is the helmholtz free energy. What I am confused about is that I thought F...
  2. L

    Which Stat Mech Text Should I Read?

    Hi, I've acquired a few stat mech texts. 1)Landau & Lif****z: A Course in Theoretical Physics: Statistical Mechanics part 1 and 2 2)Huang 3)Chandler Which of these should I start with to self-study statistical mechanics? I'm eager to read one of the famous Landau texts, but I'm afraid...
  3. H

    Stat Mech vs. Greek atomistic hypothesis?

    Has statistical mechanics anywhere disproven the ancient Greek idea that hard, indestructible objects (the original "atoms"), that experience no force other than that of impacts, can form the substratum of all material bodies and forces? I've been reading Boltzmann's "Lectures on Gas Theory"...
  4. A

    Dr. James Sethna's Stat Mech Book | Applications to Computational Stat Mech

    Check out this great book on Stat Mech by - Dr. James Sethna http://pages.physics.cornell.edu/sethna/StatMech/ This book's cool containing lots of application to Computational Stat Mech.
  5. B

    Solving for Population of Two Levels in a Two Level System: Stat Mech HW Help

    Homework Statement Consider a two level system where the ground state is doubly degenerate and the exited state of energy E is four fold degenerate. Write down the partition function and mathematical expressions for the populations of the two levels. Homework Equations z=e-E/kt ni =...
  6. E

    Conceptual Difficulty with Stat Mech

    In statistical mechanics, we define \frac{1}{\tau}=\left( \frac{\partial \sigma}{\partial U} \right)_N This formula gives the temperature as a function of the energy of the system and N. So knoweldge of U and N determines the temperature of the system. Conversely, at least when the...
  7. A

    Understanding Band Gap Models in Statistical Mechanics: Qualifying Exam Practice

    Hey folks, studying for the qualifying exam and i wanted to run this by the forum. A model system has a density of states g(E) = X for 0 < E < A g(E) = 0 for A <= E <= B g(E) = Y for B < E the total number of particles in the system is given by N = X A. Now this looks like a very simple...
  8. S

    How Does Angular Velocity Affect Gas Concentration in a Rotating Cylinder?

    A circular cylinder of radius R rotates about hte long axis with angular velocity omega. The cylinder contains an ideal gas of atoms of mass M at temperature tau. Find the expression for the dependence of the concentration n(r) on the radial distance r from the axis in terms of n(0) on the axis...
  9. L

    Proving N!/(N-n)! = N^n with Stirling's Approximation | Stat Mech HW

    I am supposed to show that N!/(N-n)! = N^n where 1<<n<<N I used stirling's approximation to show that N! = e^(NlnN-N) and (N-n)! = e^[(N-n)ln(N-n) - N + n]. I took the ratio of these two terms to get e^[NlnN-N-(N-n)ln(N-n) + N - n]. I canceled terms and get N!/(N-n)! =...
  10. S

    How Does Blackbody Radiation Relate to Standing Waves and Polarizations?

    we have a hollow cubical box with sides of length a with perfectly conducting walls, such that the electric field tangential to the surfaces of the walls must be zero. we need to show that the system of standing waves: Ex = Ax*cos(Kx*x)*sin(Ky*y)*sin(Kz*z)*exp(iwt) Ey =...
  11. S

    Why Do We Need to Outline a Proof for \beta=1/(Kb*T) in Stat Mech?

    we have to outline a proof to show that beta =1/(Kb*T) for a gas of fermions. we are supposed to put this system in thermal contact with a system obeying classical statistics, so that the two systems have the same beta, invoke the zeroth law to sat that they have the same temperature, and then...
  12. P

    Calculate Tension R of Mass m on String of Length l at Temp T

    A weight of mass m is fixed to the middle point of a string of length l and rotates about an axis joining the ends of the string. The system is in contact with its environment at temperature T. Calculate the tension R between the ends of the string in terms of its dependence upon distance x...
  13. S

    Bayesian Stat Mech reverses Entropy?

    Cosma Shalizi has a brief paper in the arxiv: http://www.arxiv.org/PS_cache/cond-mat/pdf/0410/0410063.pdf containing a proof that if you use Bayesian degree of belief oriented probability in forming statistical mechanics a la Jaynes, entropy comes out non-increasing; the arrow of time...
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