Analytic calculation of B4 for hard spheres in even dimensions
We exactly calculate the fourth virial coefficient for hard spheres in even dimensions for D=4,6,8,10, and 12.
cond-mat.stat-mech↗
arXiv subjects
B. M. McCoy
Publications and source records attributed to B. M. McCoy.
Negative virial coefficients and the dominance of loose packed diagrams for D-dimensional hard spheres
We study the virial coefficients B_k of hard spheres in D dimensions by means of Monte-Carlo integration. We find that B_5 is positive in all dimensions but that B_6 is negative for all D >= 6. For 7<=k<=17 we compute sets of Ree-Hoover diagrams and find that either for large D or large k the dominant diagrams are "loose packed". We use these results to study the radius of convergence and the validity of the many approximations used for the equations of state for hard spheres.
cond-mat.stat-mech↗
New results for the virial coefficients of D-dimensional hard spheres
Exact results are given for the fourth virial coefficient of hard spheres in even dimensions up through 12. The fifth and sixth virial coefficients are numerically computed for dimensions 2 through 50 and it is found that the sixth virial coefficient is negative for D >= 6. Numerical studies are made of the contributing Ree Hoover diagrams up to order 17. It is found for D >= 3 that for large order a class of diagrams we call "loose packed" dominates and the rate of growth of these diagrams is used to study bounds on the radius of convergence.
cond-mat.stat-mech↗
Competition of Ferromagnetic and Antiferromagnetic Order in the Spin-1/2 XXZ Chain at Finite Temperature
An analytical study is presented of the crossover in the gapless attractive XXZ chain from antiferromagnetic to ferromagnetic behaviour at low to high temperature, respectively. In particular, an analytic formula for the crossover in the long distance asymptotics and explicit results for the nearest-neighbour longitudinal correlation are obtained. We also provide results for the specific heat and magnetic susceptibility for various anisotropies.
cond-mat↗
The universal chiral partition function for exclusion statistics
We demonstrate the equality between the universal chiral partition function, which was first found in the context of conformal field theory and Rogers-Ramanujan identities, and the exclusion statistics introduced by Haldane in the study of the fractional quantum Hall effect. The phenomena of multiple representations of the same conformal field theory by different sets of exclusion statistics is discussed in the context of the ${\hat u}(1)$ theory of a compactified boson of radius $R.$
hep-th↗
The perturbations $ϕ_{2,1}$ and $ϕ_{1,5}$ of the minimal models $M(p,p')$ and the trinomial analogue of Bailey's lemma
We derive the fermionic polynomial generalizations of the characters of the integrable perturbations $ϕ_{2,1}$ and $ϕ_{1,5}$ of the general minimal $M(p,p')$ conformal field theory by use of the recently discovered trinomial analogue of Bailey's lemma. For $ϕ_{2,1}$ perturbations results are given for all models with $2p>p'$ and for $ϕ_{1,5}$ perturbations results for all models with ${p'\over 3}<p< {p'\over 2}$ are obtained. For the $ϕ_{2,1}$ perturbation of the unitary case $M(p,p+1)$ we use the incidence matrix obtained from these character polynomials to conjecture a set of TBA equations. We also find that for $ϕ_{1,5}$ with $2<p'/p < 5/2$ and for $ϕ_{2,1}$ satisfying $3p<2p'$ there are usually several different fermionic polynomials which lead to the identical bosonic polynomial. We interpret this to mean that in these cases the specification of the perturbing field is not sufficient to define the theory and that an independent statement of the choice of the proper vacuum must be made.
hep-th↗
Bailey flows and Bose-Fermi identities for the conformal coset models $(A^{(1)}_1)_N\times (A^{(1)}_1)_{N'}/(A^{(1)}_1)_{N+N'}$
We use the recently established higher-level Bailey lemma and Bose-Fermi polynomial identities for the minimal models $M(p,p')$ to demonstrate the existence of a Bailey flow from $M(p,p')$ to the coset models $(A^{(1)}_1)_N\times (A^{(1)}_1)_{N'}/(A^{(1)}_1)_{N+N'}$ where $N$ is a positive integer and $N'$ is fractional, and to obtain Bose-Fermi identities for these models. The fermionic side of these identities is expressed in terms of the fractional-level Cartan matrix introduced in the study of $M(p,p')$. Relations between Bailey and renormalization group flow are discussed.
hep-th↗
Modern Metaphysics
Metaphysics is the science of being and asks the question ``What really exists?'' The answer to this question has been sought for by mankind since the beginning of recorded time. In the past 2500 years there have been many answers to this question and these answers dominate our view of how physics is done. Examples of questions which were originally metaphysical are the shape of the earth, the motion of the earth, the existence of atoms, the relativity of space and time, the uncertainty principle, the renormalization of field theory and the existence of quarks and strings. I will explore our changing conception of what constitutes reality by examining the views of Aristotle, Ptolemy, St. Thomas Aquinas, Copernicus, Galileo, Bacon, Descartes, Newton, Leibnitz, Compte, Einstein, Bohr, Feynman, Schwinger, Yang, Gell-Mann, Wilson and Witten.
hep-th↗
Virasoro Characters from Bethe Equations for the Critical Ferromagnetic Three-State Potts Model
We obtain new fermionic sum representations for the Virasoro characters of the confromal field theory describing the ferromagnetic three-state Potts spin chain. These arise from the fermionic quasi-particle excitations derived from the Bethe equations for the eigenvalues of the hamiltonian. In the conformal scaling limit, the Bethe equations provide a description of the spectrum in terms of one genuine quasi-particle, and two ``ghost'' excitations with a limited microscopic momentum range. This description is reflected in the structure of the character formulas, and suggests a connection with the integrable perturbation of dimensions (2/3,2/3)$^+$ which breaks the $S_3$ symmetry of the conformal field theory down to $Z_2$.
hep-th↗
Fermionic Sum Representations for Conformal Field Theory Characters
We present sum representations for all characters of the unitary Virasoro minimal models. They can be viewed as fermionic companions of the Rocha-Caridi sum representations, the latter related to the (bosonic) Feigin-Fuchs-Felder construction. We also give fermionic representations for certain characters of the general $(G^{(1)})_k \times (G^{(1)})_l \over (G^{(1)})_{k+l}}$ coset conformal field theories, the non-unitary minimal models ${\cal M}(p,p+2)$ and ${\cal M}(p,kp+1)$, the $N$=2 superconformal series, and the $\ZZ_N$-parafermion theories, and relate the $q\to 1$ behaviour of all these fermionic sum representations to the thermodynamic Bethe Ansatz.
hep-th↗
Quasi-Particles, Conformal Field Theory, and $q$-Series
We review recent results concerning the representation of conformal field theory characters in terms of fermionic quasi-particle excitations, and describe in detail their construction in the case of the integrable three-state Potts chain. These fermionic representations are $q$-series which are generalizations of the sums occurring in the Rogers-Ramanujan identities. (To appear in the proceedings of ``Yang-Baxter Equations in Paris'', July 1992, J.-M.~Maillard (ed.).)
hep-th↗
Fermionic Quasi-Particle Representations for Characters of ${(G^{(1)})_1 \times (G^{(1)})_1 ø(G^{(1)})_2}$
We present fermionic quasi-particle sum representations for some of the characters (or branching functions) of ~${(G^{(1)})_1 \times (G^{(1)})_1 ø(G^{(1)})_2}$ ~for all simply-laced Lie algebras $G$. For given $G$ the characters are written as the partition function of a set of rank~$G$ types of massless quasi-particles in certain charge sectors, with nontrivial lower bounds on the one-particle momenta. We discuss the non-uniqueness of the representations for the identity character of the critical Ising model, which arises in both the $A_1$ and $E_8$ cases.
hep-th↗