Partition function Definition and 182 Threads

Homework Statement I. Finding the partition function Z. II. If the middle level (only) is degenerate, i.e. there are two states with the same energy, show that the partition function is: Z = (1+exp(\frac{-\epsilon}{k_{B}T}))^{2} III. State the Helmholtz free energy F of the...

In looking at phonons, and their energy, I came across the Partition function. THis was needed to calculate the internal energy of the solid. But howcome the Partition function is used, and not the GRAND Partition function? The number of phonons is not conserved, I know that, but isn't N, the...

Homework Statement This is just a general question, not a "problem" Homework Equations Z = sum(e^Ej/kT) The Attempt at a Solution I'm working on a problem in which I'm asked to find the probabilities of an electron in a hydrogen atom being at one of three energies. The...

Question is on attachment file.

I am reading a book (Di Francesco's "CFT", pg 337) in which it is given that if we take the operator that translates the system along some direction (which is a combination of time and space) as 'A', then the partition function is just trace(A). How do we get this?

Homework Statement Calculate fermi energy, fermi temp and fermi wave vector. a)Protons with n= 1.0E43 m^{-3} b) ^{3}He in liquid He (atomic volume= 46E^-3 m^3 Homework Equations E_f=\frac{h^2}{8 m} (\frac{3 n}{\pi V})^\frac{2}{3} T_f= \frac{E_f}{k_B} The Attempt at a Solution I get the...

Homework Statement By shining and intense laser beam on to a semiconductor, one can create a collection of electrons (charge -e, and effective mass me) and holes (charge +e, and effective mass mh) in the bulk. The oppositely charged particle may pair up (as in a hydrogen atom) to form a gas of...

Does there exist a database for the Partition function at different temperatures? As I understand it it only varies with temperature and is otherwise the same for the species. I am looking for the partition function for C02 at T=1000K.

Homework Statement This is the integration i have to solve I=\int x^{2}In(1-exp(-ax))dx integration is from zero to infinity The Attempt at a Solution I know that it should be solved with integration by parts so u=In(1-exp(-ax)) du=[a exp(-ax)] / [1-exp(-ax)] dv=x^{2}dx...

Hello! I've got a problem. If you scroll down to page 118 on the following link http://books.google.com/books?id=ntrPDA6zE1wC&dq=Quarks+bound+by+chiral+fields&pg=PP1&ots=_29vGOurGs&source=bn&sig=h4vGPNBbKX14DpoOyt4tuRZHkRc&hl=de&sa=X&oi=book_result&resnum=4&ct=result#PPA118,M1 there you...

I am aware that there are several generator functions for the Partition Function p(n), but does anyone know if a closed form formula exists for this function?

Homework Statement For a magnetic particle with an angular momentum "quantum number", j, the allowed values of the z component of a particles magnetic moment are: µ = -jδ, (-j + 1)δ, ..., (j-1)δ, jδ δ is a constant, and j is a multiple of 1/2 Show that the partition function of a...

The question: A system consists of N sites and N particles with magnetic moment m. each site can be in one of the three situations: 1. empty with energy zero. 2. occupied with one particle and zero energy (when there isn't magnetic field around). 3. occupied with two particles with anti...

given a partition function of the form Z[u]= \prod Z_{i} [u] Z_{i} [u] = \sum_{n=-\infty}^{\infty}e^{iuE_{n}^{i}} what is the meaning of zeros ? i mean the values that make Z[u]=0 and how could we calculate these zeros ??

Homework Statement Does anyone know the mathematical definition of the microcanonical partition function? I've seen \Omega = {E_0\over{N!h^{3n}}}\int d^{3N}q d^{3N}p \delta(H - E) where H=H(p,q) is the Hamiltonian. This looks like a useful definition. Only thing is I don't know what E_0...

Homework Statement If we have a system of N independent particles and the partition function for one particle is Z_1, then is the partition function for the N particle system Z=(Z_1)^N? Homework Equations The Attempt at a Solution I'm pretty sure that this is true for a classical...

Homework Statement A certain magnetic system has N independent molecules per unit volume, each of which as 4 distinct energy levels: 0, \Delta - \mu_BB, \Delta, \Delta + \mu_BB. i) Write down the partition function, and hence find an expression for the Hemholtz function ii) Use this...

given a partition function Tr[e^{-BH}] or Z(B)= \int_{P}dx dp e^{-BH(p,q)} is there any meaning for its zeros ? , i mean what happens in case the partition function Z(B)=0 for some 'B' or temperature B=1/kT do these zeros have a meaning ?? thanks

Is it possible to obtain the relation S = \log Z + \langle U \rangle /T directly from the Boltzmann distribution? Edit: It seems that we can if we use the VN entropy: S = -\Sigma p_i \log p_i This suggests that the entropy of a single microstate should be s = -\log( \frac{e^{-\epsilon...

Partition function for a gas in a cylinder -- urgent! Hi, Here's the problem -- it's supposed to be a specimen of what I can expect in my exam, but it isn't much like the tutorial questions I've been doing. I'd really appreciate some help -- fast! Homework Statement An ideal gas consisting...

Is the energy given by the first or the second? I have seen both relationships in different websites, and I am confused. E = kT^2 \frac{\partial Z}{\partial T} or E = - \frac{\partial ln Z}{\partial \beta}

The partition function in the classical theory is an integral over phase space. Thus, the partition function is often not dimensionless. Then the formula F = -T \log Z can no longer be valid, as you can only take the logarithm of a dimensionless number. In the quantum theory, this...

What is the relation between the partition function and the Boltzman, Maxwell distribution? Differences and similarities? Both have exponentials to the power of the negative total energy of the microstate. Although the word microstate dosen't occur in the Boltzman, Maxwell case. Is the BM...

Homework Statement When modeling ideal gas molecules using a grand partition ensemble, is heat flow = 0? So if U=Q-W then in a grand canonical ensemble, U=-W?The Attempt at a Solution I think so as the system is in thermal equilibrium with the surroundings. So in this system the total energy is...

Let us consider a collection of non-interacting hydrogen atoms at a certain temperature T. The energy levels of the hydrogen atom and their degeneracy are: En = -R/n² gn = n² The partition function in statistical physics is given by: Z = Sum(gn Exp(-En/kT), n=1 to Inf) This...

If I have a 2 state system with energy levels of the 2 states to be 0 and V. I find the partition function to be Z = 1 + e^(-V/kT). Am I correct? If so, does that not mean the average energy is V? and thus the entropy is 0? This doesn't make sense, how is the entropy of a 2 state system (when 1...

Let be the continuous partition function: Z(\beta)=(N!)^{-1}\int_{V}dx_1 dx_2 dx_3 dx_4 ...dx_N exp(-\beta H(x_1, x_2 , x_3 , ... ,x_n,p_1 , p_2 , ..., p_N if the Hamiltonian is 'quadratic' in p's are q's do this mean that the particles in the gas solid or whatever follow a Normal...

bah nevermind the question is too complicated to even write down :cry: i hate this :(

Let be the Hamiltonian Energy equation: H\Psi= E_{n} \Psi then let be the partition function: Z=\sum_{n} g(n)e^{-\beta E_{n}} where the "Beta" parameter is 1/KT k= Boltzmann constant..the question is..let,s suppose we know the "shape" of the function Z...could we then "estimate"...

This is a question about thermal physics. There's this partition function Z = sum over all states s of the system ( exp(-E_s/T)). And its just used to calculate the probability of any state by taking the Boltzman factor exp(-E_s/T) of that state and dividing over the partition function. Theres...

I got a problem by finding an proper explanation. The Boltzmann factor is defined as P_j=\frac{1}{Z}e^{-\beta E_j} I know, this is a probability distribution. but what exactly does it mean? Wikipedia says: "The probability Pj that the system occupies microstate j" (link) But that doesen...

Hi, i'm having trouble with a thermal physics problem relating to the partition function and i was wondering if anyone could help me out. the problem is as follows: (a) Consider a molecule which has energy levels En=c|n| , where n is a vector with integer components. Compute the partition...