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G. Sardanashvily

Publications and source records attributed to G. Sardanashvily.

At least 55 records · Page 3Linked to original sources
arXiv2007

The KT-BRST complex of a degenerate Lagrangian system

Quantization of a Lagrangian field system essentially depends on its degeneracy and implies its BRST extension defined by sets of non-trivial Noether and higher-stage Noether identities. However, one meets a problem how to select trivial and non-trivial higher-stage Noether identities. We show that, under certain conditions, one can associate to a degenerate Lagrangian L the KT-BRST complex of fields, antifields and ghosts whose boundary and coboundary operators provide all non-trivial Noether identities and gauge symmetries of L. In this case, L can be extended to a proper solution of the master equation.

math-ph↗
arXiv2007

Supermetrics on supermanifolds

By virtue of the well-known theorem, a structure Lie group K of a principal bundle $P$ is reducible to its closed subgroup H iff there exists a global section of the quotient bundle P/K. In gauge theory, such sections are treated as Higgs fields, exemplified by pseudo-Riemannian metrics on a base manifold of P. Under some conditions, this theorem is extended to principal superbundles in the category of G-supermanifolds. Given a G-supermanifold M and a graded frame superbundle over M with a structure general linear supergroup, a reduction of this structure supergroup to an orthgonal-symplectic supersubgroup is associated to a supermetric on a G-supermanifold M.

math-ph↗
arXiv2007

On the mathematical origin of quantum space-time

An Euclidean topological space E is homeomorphic to the subset of delta-functions of the space D'(E) of Schwartz distributions on E. Herewith, any smooth function of compact support on E is extended onto D'(E). One can think of these extensions as sue generis quantum deformations. In quantum models, one therefore should replace integration of functions over E with that over D(E).

math-ph↗
arXiv2007

Relative non-relativistic mechanics

Dynamic equations of non-relativistic mechanics are written in covariant-coordinate form in terms of relative velocities and accelerations with respect to an arbitrary reference frame. The notions of the non-relativistic reference frame, inertial force, free motion equation, and inertial frame are discussed.

math-ph↗
arXiv2007

Graded infinite order jet manifolds

The relevant material on differential calculus on graded infinite order jet manifolds and its cohomology is summarized. This mathematics provides the adequate formulation of Lagrangian theories of even and odd variables on smooth manifolds in terms of the Grassmann-graded variational bicomplex.

math-ph↗
arXiv2007

Axiomatic quantum field theory. Jet formalism

Jet formalism provides the adequate mathematical formulation of classical field theory, reviewed in hep-th/0612182v1. A formulation of QFT compatible with this classical one is discussed. We are based on the fact that an algebra of Euclidean quantum fields is graded commutative, and there are homomorphisms of the graded commutative algebra of classical fields to this algebra. As a result, any variational symmetry of a classical Lagrangian yields the identities which Euclidean Green functions of quantum fields satisfy.

hep-th↗
arXiv2007

Quantum mechanics with respect to different reference frames

Geometric (Schrodinger) quantization of nonrelativistic mechanics with respect to different reference frames is considered. In classical nonrelativistic mechanics, a reference frame is represented by a connection on a configuration space fibered over a time axis. Under quantization, it yields a connection on the quantum algebra of Schrodinger operators. The operators of energy with respect to different reference frames are examined.

quant-ph↗
arXiv2006

Axiomatic classical (prequantum) field theory. Jet formalism

In contrast with QFT, classical field theory can be formulated in a strict mathematical way if one defines even classical fields as sections of smooth fiber bundles. Formalism of jet manifolds provides the conventional language of dynamic systems (nonlinear differential equations and operators) on fiber bundles. Lagrangian theory on fiber bundles is algebraically formulated in terms of the variational bicomplex of exterior forms on jet manifolds where the Euler--Lagrange operator is present as a coboundary operator. This formulation is generalized to Lagrangian theory of even and odd fields on graded manifolds. Cohomology of the variational bicomplex provides a solution of the global inverse problem of the calculus of variations, states the first variational formula and Noether's first theorem in a very general setting of supersymmetries depending on higher-order derivatives of fields. A theorem on the Koszul--Tate complex of reducible Noether identities and Noether's inverse second theorem extend an original field theory to prequantum field-antifield BRST theory. Particular field models, jet techniques and some quantum outcomes are discussed.

hep-th↗
arXiv2006

Reduction of principal superbundles, Higgs superfields, and supermetric

By virtue of the well-known theorem, a structure Lie group G of a principal bundle P is reducible to its closed subgroup H iff there exists a global section of the quotient bundle P/H. In gauge theory, such sections are treated as classical Higgs fields, and are exemplified by Riemannian and pseudo-Riemannian metrics. This theorem is extended to a certain class of principal superbundles, including a graded frame superbundle with a structure general linear supergroup. Each reduction of this structure supergroup to an orthgonal-symplectic supersubgroup is associated to a supermetric on a base supermanifold.

hep-th↗
arXiv2006

Noether's inverse second theorem in homology terms

A generic degenerate Lagrangian system of even and odd variables on an arbitrary smooth manifold is examined in terms of the Grassmann-graded variational bicomplex. Its Euler-Lagrange operator obeys Noether identities which need not be independent, but satisfy first-stage Noether identities, and so on. However, non-trivial higher-stage Noether identities are ill defined, unless a certain homology condition holds. We show that, under this condition, there exists the exact Koszul-Tate chain complex whose boundary operator produces all non-trivial Noether and higher-stage Noether identities of an original Lagrangian system. Noether's inverse second theorem that we prove associates to this complex a cochain sequence whose ascent operator provides all gauge and higher-stage gauge supersymmetries of an original Lagrangian.

math.DG↗
arXiv2006

Lagrangian and Hamiltonian dynamics of submanifolds

Submanifolds of a manifold are described as sections of a certain fiber bundle that enables one to consider their Lagrangian and (polysymplectic) Hamiltonian dynamics as that of a particular classical field theory. In particular, their Lagrangians and Hamiltonians must satisfy rather restrictive Noether identities. For instance, this is the case of relativistic mechanics and classical string theory.

math-ph↗
arXiv2006

Lagrangian BV quantization and Ward identities

The Ward identities are the relations which the complete Green functions of quantum fields satisfy if an original classical Lagrangian system is degenerate. A generic degenerate Lagrangian system of even and odd fields is considered. It is characterized by a hierarchy of reducible Noether identities and gauge supersymmetries parameterized by antifields and ghosts, respectively. In the framework of the BV quantization procedure, an original degenerate Lagrangian is extended to ghosts and antifields in order to satisfy the master equation. Replacing antifields with gauge fixing terms, one comes to a non-degenerate Lagrangian which is quantized in the framework of perturbed QFT. This Lagrangian possesses a BRST symmetry. The corresponding Ward identities are obtained. They generalize Ward identities in the Yang-Mills gauge theory to a general case of reducible gauge supersymmetries depending on derivatives of fields of any order. A supersymmetric Yang-Mills model is considered.

hep-th↗
arXiv2006

Geometry of classical Higgs fields

In gauge theory, Higgs fields are responsible for spontaneous symmetry breaking. In classical gauge theory on a principal bundle P, a symmetry breaking is defined as the reduction of a structure group of this principal bundle to a subgroup H of exact symmetries. This reduction takes place iff there exists a global section of the quotient bundle P/H. It is a classical Higgs field. A metric gravitational field exemplifies such a Higgs field. We summarize the basic facts on the reduction in principal bundles and geometry of Higgs fields. Our goal is the particular covariant differential in the presence of a Higgs field.

hep-th↗