Some eigenstates for a model associated with solutions of tetrahedron equation. IV. String-particle marriage

This paper continues the series begun with works solv-int/9701016, solv-int/9702004 and solv-int/9703010. Here we construct more sophisticated strings, combining ideas from those papers and some considerations involving solutions of tetrahedron equation due to Sergeev, Mangazeev and Stroganov.Comment: LaTeX, 6 page

Tetrahedron equation and the algebraic geometry

The tetrahedron equation arises as a generalization of the famous Yang--Baxter equation to the 2+1-dimensional quantum field theory and the 3-dimensional statistical mechanics. Very little is still known about its solutions. Here a systematic method is described that does produce non-trivial solutions to the tetrahedron equation with spin-like variables on the links. The essence of the method is the use of the so-called tetrahedral Zamolodchikov algebras.Comment: 12 pages, to appear in ``Zapiski Nauchnyh Seminarov POMI'', S-Petersburg (English translation of a part of the author's Ph.D. Thesis, S-Petersburg, 1990

Integrability in 3+1 Dimensions: Relaxing a Tetrahedron Relation

I propose a scheme of constructing classical integrable models in 3+1 discrete dimensions, based on a relaxed version of the problem of factorizing a matrix into the product of four matrices of a special form.Comment: LaTeX, 3 page

A formula with volumes of five tetrahedra and discrete curvature

Given five points in a three-dimensional euclidean space, one can consider five tetrahedra, using those points as vertices. We present a pentagon-like formula containing the product of three volumes of those tetrahedra in its l.h.s. and the product of the two remaining tetrahedron volumes in its r.h.s., as well as the derivative of the "discrete curvature" which arises when we slightly deform our euclidean space.Comment: LaTeX, 2 pages. An addendum to solv-int/991100

Three-dimensionalizing the eight-vertex model

A simple ansatz is proposed for two-color R-matrix satisfying the tetrahedron equation. It generalizes, on one hand, a particular case of the eight-vertex model to three dimensions, and on another hand - Hietarinta's permutation-type operators to their linear combinations. Each separate R-matrix depends on one parameter, and the tetrahedron equation holds provided the quadruple of parameters belongs to an algebraic set containing five irreducible two-dimensional components.Comment: 7 pages, 3 figures. v2: Fig. 3 correcte

Some eigenstates for a model associated with solutions of tetrahedron equation

Here we present some eigenstates for a 2+1-dimensional model associated with a solution of the tetrahedron equation. The eigenstates include those "particle-like" (namely one-particle and two-particle ones), constructed in analogy with the usual 1+1-dimensional Bethe ansatz, and some simple "string-like" ones.Comment: 7 pages, LaTe

Some eigenstates for a model associated with solutions of tetrahedron equation. V. Two cases of string superposition

In paper IV (solv-int/9704013) we have considered a string living in the infinite lattice that was, in a sense, generated by a "particle". Here we show how to construct multi-string eigenstates generated by several particles. It turns out that, at least in some cases, this allows us to bypass the difficulties of constructing multi-particle states. We also present and discuss the "dispersion relations" for our particles-strings.Comment: LaTeX, 7 page

Vacuum curves, classical integrable systems in discrete space-time and statistical physics

A dynamical system with discrete time is studied by means of algebraic geometry. The system admits a reduction that is interpreted as a classical field theory in 2+1-dimensional wholly discrete space-time. The integrals of motion of a particular case of the reduced system are shown to coincide, in essence, with the statistical sum of the well-known (inhomogeneous) 2-dimensional dimer model (the statistical sum is here a function of two parameters). Possible generalizations of the system are examined.Comment: 18 pages. Talk made at the Lobachevsky Semester in Euler International Math Institute, S Petersburg, November 199

A formula with hypervolumes of six 4-simplices and two discrete curvatures

One of the generalizations of the pentagon equation to higher dimensions is the so-called "six-term equation". Geometrically, it corresponds to one of the "Alexander moves", that is elementary rebuildings of simplicial complexes, namely, replacing a "cluster" of three 4-simplices by another "cluster", also of three 4-simplices and with the same boundary. We present a formula containing the euclidean volumes of the simplices in the first cluster in its l.h.s., and those in the second cluster - in its r.h.s. The formula also involves "discrete curvatures" appearing when we slightly deform the euclidean space.Comment: LaTeX, 3 pages, continues solv-int/9911008 and nlin.SI/000300

A Dynamical System Connected with Inhomogeneous 6-Vertex Model

A completely integrable dynamical system in discrete time is studied by means of algebraic geometry. The system is associated with factorization of a linear operator acting in a direct sum of three linear spaces into a product of three operators, each acting nontrivially only in a direct sum of two spaces, and the following reversing of the order of factors. There exists a reduction of the system interpreted as a classical field theory in 2+1-dimensional space-time, the integrals of motion coinciding, in essence, with the statistical sum of an inhomogeneous 6-vertex free-fermion model on the 2-dimensional kagome lattice (here the statistical sum is a function of two parameters). Thus, a connection with the ``local'', or ``generalized'', quantum Yang--Baxter equation is revealed.Comment: 21 page