Thermodynamic limit of correlation functions in a system of gravitating fermions

We show that the correlation functions in a system of gravitating fermions converge as tempered distributions in the thermodynamic limit, if the system is not at the point of phase-transition. The densities converge to the density of the Thomas-Fermi-theory and are not correlated in the limit.     

Free fermions and tau-functions

We review the formalism of free fermions used for construction of tau-functions of classical integrable hierarchies and give a detailed derivation of group-like properties of the normally ordered exponents, transformations between different normal orderings, the bilinear relations, the generalized Wick theorem and the bosonization rules. We also consider various examples of tau-functions and give their fermionic realization.     

Free fermions and the Alexander-Conway polynomial

We show how the Conway Alexander polynomial arises from theq deformation of (Z ₂ graded)sl(n, n) algebras. In the simplestsl(1, 1) case we then establish connection between classical knot theory and its modern versions based on quantum groups. We first shown how the crystal and the fundamental group of the complement of a knot give rise naturally to the Burau representation of the braid group. The Burau matrix is then transformed into theU _q sl(1, 1) R matrix by going to the exterior power algebra. Using a det=str identity, this allows us to recover the state model of [K2, 89] as well. We also show how theU _q> sl(1, 1) algebra describes free fermions propagating on the knot diagram. We rewrite the Conway Alexander polynomial as a Berezin integral, and thus as an apparently new determinant.Work supported in part by NSF grant no. DMS-8822602Work supported in part by the NSF: grant nos. PYI PHY 86-57788 and PHY 90-00386 and by CNRS, France     

Free fermions and WZW theories on nonsimple groups

We consider conformally and Kac-Moody invariant theories based on the groupsG=G(N)×G(Ñ) whereG(N) is any of the classical groups. For the valuesk=Ñ, \(\tilde k = N\) of the Kac-Moody central charges, the monodromy problem involved in the computation of the four point function for primary fields in the defining representation ofG possesses two distinct solutions. As a consequence, the WZW theory onG (with an additionalU(1) factor ifG(N)=SU (N)) cannot be equivalent to a theory of free fermions.     

Free fermions on a three-dimensional lattice and tetrahedron equations

A method to construct a commuting transfer matrix has been proposed for three-dimensional fermion field theory. The method is based on the use of “tetrahedron equations”. For the case of free fermions, the commuting transfer matrix structure has been studied completely and some solution has been obtained for the tetrahedron equations.     

Remarks on binding energy of fermions in Newtonian gravity

The clarifications made regarding the binding energy in connection with a model for the internal structure of black holes are shown to be incorrect.     

An uncertainty principle for fermions with generalized kinetic energy

We derive semiclassical upper bounds for the number of bound states and the sum of negative eigenvalues of the one-particle Hamiltoniansh=f(?i?)+V(x) acting onL ²(?ⁿ). These bounds are then used to derive a lower bound on the kinetic energy \(\sum\limits_{j = 1}^N {\left\langle {\psi ,f( - i\nabla _j )\psi } \right\rangle }\) for anN-fermion wavefunction ψ. We discuss two examples in more detail:f(p)=|p| andf(p)=(p ²+m ²)^1/2?m, both in three dimensions.     

Free energy of electrolyte solutions

The energy of formation of ionic hydrate complexes in infinitely dilute solutions was calculated using the molecular mechanics method. It was found that the OPLS force field is most preferable for calculating the energy of ionic hydration. A correlation relationship between the calculated and experimental energies of ion hydration was derived.     

Abelian model of gravitating magnetic monopole

A self-consistentU(1)-gauge model in gravitational field is investigated. The exact solutions of two types of corresponding field equations are obtained. These solutions can be interpreted as magnetic monopoles. The first solution is regular forr 0 and provides an everywhere regular geometry, the second one has a physical singularity. In order to guarantee the stability of the monopoles we introduce the notion of a gravitational topological charge using de Rham's cohomology theory. This topological charge describes the sizes and the inner structure of the monopole.     

Free energy of a spin glass

We give the theory of a model spin glass of the Sherrington-Kirkpatrick type. Determining that the free energy is given by the potential function of a two-dimensional electrostatic medium, we find exact expressions for this quantity in terms of a multipole expansion of the charge distribution. We also obtain the internal energy, entropy, and specific heat in the form of explicit integrals over the multipole distributions. Pending the outcome of a quantitative investigation into the structure of these functions, here we discuss their properties in a qualitative way.     

Free energy of multiple overlapping chains

How accurate is pair additivity in describing interactions between soft polymer-based nanoparticles? Using numerical simulations we compute the free energy cost required to overlap multiple chains in the same region of space, and provide a quantitative measure of the effectiveness of pair additivity as a function of chain number and length. Our data suggest that pair additivity can indeed become quite inadequate as the chain density in the overlapping region increases. We also show that even a scaling theory based on polymer confinement can only partially account for the complexity of the problem. In fact, we unveil and characterize an isotropic to star-polymer crossover taking place for large number of chains, and propose a revised scaling theory that better captures the physics of the problem.