Phase diagrams and cluster expansions for low temperatureP(φ)2 models

We give a cluster expansion for the Schwinger functions of the stable phases found in Part I. The Wightman axioms, the mass gap, and asymptoticity of perturbation theory follow.Supported in part by the National Science Foundation under Grant No. PHY 79-16812National Science Foundation predoctoral fellow, 1979–80. Currently Junior Fellow, Harvard University Society of Fellows     

Eigenvalue inequalities for fermions in gauge theories

We show that QCD with a sufficient number of fermions of zero bare mass has physical massless particles. That result also follows from triangle anomalies, so only our method is novel. Our method involves proving special cases of recently conjectured paramagnetic inequalities for fermions. The proofs are simple applications of the Atiyah-Patodi-Singer theorem on spectral flow.Supported in part by the National Science Foundation Grant No. PHY80-19754Supported in part by DOE Grant No. DE-AC02-76ER02220     

Heat kernel regularization of quantum fields

We discuss some consequences of the existence of a heat kernel regularization (HKR) for quantum fields. We demonstrate that HKR applies in certain examples, using methods which should be useful more generally.Supported in part by the National Science Foundation under Grant PHY/DMS 86-45122Supported in part by a German National Scholarship Foundation fellowship     

Existence of conserved currents in the perturbative sine-Gordon and massive thirring models

The existence of infinitely many conserved currents in the quantized sine-Gordon and massive Thirring models is proved in renormalized perturbation theory.Research supported in part by National Science Foundation Grant No. PHY 74-22218 A03Research supported in part by National Science Foundation Grant No. MP 574-05783 A01     

Surface integrals and monopole charges in non-abelian gauge theories

We derive a formula which gives all the magnetic charges (topological invariants) of a monopole in the adjoint representation of a non-abelian gauge theory in terms of surface integrals at infinity.Supported in part by the National Science Foundation under Grant No. PHY 79-16812Junior Fellow, Harvard University Society of Fellows     

An existence theorem for multimeron solutions to classical Yang-Mills field equations

In this paper we prove the existence of solutions to a class of boundary value problems for a singular nonlinear elliptic partial differential equation in a half plane. By a recent paper of J. Glimm and A. Jaffe, this proves the existence of multimeron solutions to the classical SU(2) Yang-Mills field equations in Euclidean space.Supported in part by the National Science Foundation under Grant PHY 77-18762Supported in part by the Icelandic Science FoundationSupported in part by Grant MCS 76-06524     

Supersymmetry and the spectral condition on a cylinder

We study the spectral condition for supersymmetric Wess-Zumino field theories on a cylindrical spacetime. This condition is preserved under certain ultraviolet cutoff procedures and also leads to analyticity of HKR regularized field operators in a complex neighborhood of spacetime.Supported in part by the National Science Foundation under Grant DMS/PHY86-45122.Supported in part by a German National Scholarship.     

Pair function for the rectangular Ising ferromagnet

A representation of the pair correlation function for the rectangular Ising model in zero magnetic field is derived using a new spinor technique; this enables the scaling limit to be established, as well as several analytical properties of the scaling functions.Supported by the Fonds National Suisse de la Recherche Scientifique, by the National Science Foundation Grant No. PHY76-17191, and by the National Research Council of Canada Grant No. NRC A9344     

n-point functions for the rectangular Ising ferromagnet

A new representation for then-point functions of the Planar Ising ferromagnet is given. Below the critical temperature the boundary conditions are toroidal; the state is a superposition of the extremal invariant ones, with equal weights.Supported by the Fonds National Suisse de la Recherche Scientifique, by the National Science Foundation Grant No. PHY 76-17191, and by the National Research Council of Canada Grant No. NRC A 9344     

Topology of monopole catalysis

We give the necessary mathematical conditions for strong monopole catalysis.Researach supported in part by the National Science Foundation under Grant No PHY 82-15249.     

Odd operators and spinor algebras in lattice statistics:n-point functions for the rectangular Ising model

An extension is given of the development by Schultz et al. [3] of the pioneering work of Kaufman and Onsager [2] on the planar Ising ferromagnet. This involves a novel form of Wick's theorem [19] for fermions. In subsequent papers the method will be applied to determine then-point functions and to evaluate rigorously critical indices.Supported by the Fonds National Suisse de la Recherche Scientifique, by the National Science Foundation Grant No. PHY76-17191, and by the National Research Council of Canada Grant No. NRC A9344     

On Witten's proof of the positive energy theorem

This paper gives a mathematically rigorous proof of the positive energy theorem using spinors. This completes and simplifies the original argument presented by Edward Witten. We clarify the geometric aspects of this argument and prove the necessary analytic theorems concerning the relevant Dirac operator.Supported in part by the National Science Foundation under Grant PHY79-16812Junior Fellow, Harvard University Society of Fellows     

Debye screening for jellium and other Coulomb systems

Debye screening is proven for a large class of classical Coulomb gases at low densities. Among the models treated are jellium systems (where particles interact with a fixed background charge), systems with arbitrarily dilute fractional charges, and systems where the charges are not integrally related. The interaction potentials of the corresponding sine-Gordon models may have no symmetry and can have infinitely many stationary points which are degenerate or nearly degenerate in energy.Junior Fellow, Harvard University Society of Fellows. Supported in part by the National Science Foundation under Grant No. PHY79-16812     

O(3) symmetric merons in an SU(3) Yang-Mills theory

We investigate irreducible, O(3) symmetric multiple-meron solutions to the classical SU(3) Yang-Mills equations in four-dimensional Euclidean space. The solutions have topological charge density equal to a sum of delta-functions with integer coefficients, and correspond to solutions of a system of two coupled singular elliptic equations. We prove the existence of twomeron solutions of the coupled system.Supported in part by the National Science Foundation under Grant No. PHY77-18762.     

The global existence of Yang-Mills-Higgs fields in 4-dimensional Minkowski space

In this paper and its sequel we shall prove the local and then the global existence of solutions of the classical Yang-Mills-Higgs equations in the temporal gauge. This paper proves local existence uniqueness and smoothness properties and improves, by essentially one order of differentiability, previous local existence results. Our results apply to any compact gauge group and to any invariant Higgs self-coupling which is positive and of no higher than quartic degree.Supported in part by the National Science Foundation (Grant No. PHY79-16482 at Yale)     

Space-dependent dirac operators and effective quantum field theory for fermions

For the operator, wherem(x) can change sign, we develop a cluster expansion for computing the determinant and Green's functions. We use a local chiral transformation to relate the space-dependent case to the ordinary Dirac operator.Supported in part by National Science Foundation grant PHY/DMS 88-16214Supported in part by National Science Foundation grants DMS 90-08827 and DMS 88-580873Supported in part by National Science Foundation Mathematical Sciences Postdoctoral Research Fellowship DMS 88-07291     

Boundary terms in the action for the Regge calculus

The boundary terms in the action for Regge's formulation of general relativity on a simplicial net are derived and compared with the boundary terms in continuum general relativity.Supported in part by the National Science Foundation grants PHY 78-09620 and PHY 78-24275.     

A time dependent Born-Oppenheimer approximation

We consider the dynamics of a quantum mechanical system which consists of some particles with large masses and some particles with small masses. As we increase the large masses to infinity we obtain the following results: The particles of smaller mass move adiabatically and determine an effective potential in which the heavier particles move semiclassically. Our methods can be applied to diatomic molecules with Coulomb forces.Supported in part by the National Science Foundation under Grant PHY 78-08066     

1/n expansion for a Quantum Field Model

A nonperturbative study of the 1/n expansion in Euclidean Quantum Field Theory is started. The expansion is shown to be asymptotic to the vacuum energy of the (²) ₂ ² model, for arbitrary coupling constant.Supported in part by the National Science Foundation under Grant No. PHY 79-16812     

Gross-Neveu model through convergent perturbation expansions

We construct a continuum limit for the effective low energy Lagrangians of the Gross-Neveu model in two euclidean dimensions by showing that they are related to each other through convergent perturbation expansions. This provides a rigorous control of the ultraviolet problem in a renormalizable quantum field theory.Supported in part by the National Science Foundation under Grant MCS-81-20833Supported in part by the National Science Foundation under Grant PHY-82-03669