Using techniques of effective field theory, we consider the thermodynamical properties of a dilute two-dimensional plasma interacting via a 1/r potential. The first one-loop correction to the partition function is already logarithmically divergent in the effective theory. The finite part of the one-loop induced couplings is then explicitly evaluated by matching the density-density correlator in...

In this paper we extend the geometric formalism of the Hamilton-Jacobi theory for hamiltonian mechanics to the case of classical field theories in the framework of multisymplectic geometry and Ehresmann connections.

Arnaud Beauville’s survey ”Vector bundles on Curves and Generalized Theta functions: Recent Results and Open Problems” [Be] appeared 10 years ago. This elegant survey is short (16 pages) but provides a complete introduction to a specific part of algebraic geometry. To repeat his succes now we need more pages, even though we assume that the reader is already acquainted with the material presente...

In a previous paper [hep-th/0012251] we proposed a simple class of actions for string field theory around the tachyon vacuum. In this paper we search for classical solutions describing D-branes of different dimensions using the ansatz that the solutions factorize into the direct product of a matter state and a universal ghost state. We find closed form expressions for the matter state describin...

We calculate the far-from-equilibrium dynamics and thermalization both for the quantum and the classical O(N)–model. The early and late-time behavior can be described from the 2PI–loop expansion for weak couplings or the nonperturbative 2PI–1/N expansion of the effective action beyond leading order. A comparison with exact simulations in 1+1 dimensions in the classical limit shows that the 2PI–...

Matched asymptotic expansion is a useful technique in General Relativity and other fields whenever interaction takes place between physics at two different length scales. Here matched asymptotic expansion is argued to be equivalent quite generally to Classical Effective Field Theory (ClEFT) where one (or more) of the zones is replaced by an effective theory whose terms are organized in order of...

In this paper we discuss a Schwinger-Dyson [SD] approach for determining the time evolution of the unequal time correlation functions of a non-equilibrium classical field theory, where the classical system is described by an initial density matrix at time t = 0. We focus on λφ4 field theory in 1+1 space time dimensions where we can perform exact numerical simulations by sampling an ensemble of ...

Using two new well defined 4-dimensional potential vectors, we formulate the classical Maxwell’s field theory in a form which has manifest Lorentz covariance and SO(2) duality symmetry in the presence of magnetic sources. We set up a consistent Lagrangian for the theory. Then from the action principle we get both Maxwell’s equation and the equation of motion of a dyon moving in the electromagne...

Based on a number of experimentally verified physical observations, it is argued that the standard principles of quantum mechanics should be applied to the Universe as a whole. Thus, a paradigm is proposed in which the entire Universe is represented by a pure state wavefunction contained in a factorisable Hilbert space of enormous dimension, and where this statevector is developed by successive...

We approximate a (spatially cutoff) (φ4)2 Euclidean field theory by an ensemble of spin 1/2 Ising spins with ferromagnetic pair interactions. This approximation is used to prove a Lee-Yang theorem and GHS type correlation inequalities for the (0 4 ) 2 theory. Application of these results are presented.