arXiv subjects

D. V. Boulatov

Publications and source records attributed to D. V. Boulatov.

11 recordsLinked to original sources

arXiv2000

Recursive sampling simulations of 3D gravity coupled to scalar fermions

We study numerically the phase structure of a model of 3D gravity interacting with scalar fermions. We measure the 3D counterpart of the "string" susceptibility exponent as a function of the inverse Newton coupling $α$. We show that there are two phases separated by a critical point around $α_c \simeq 2$. The numerical results support the hypothesis that the phase structures of 3D and 2D simplicial gravity are qualitatively similar, the inverse Newton coupling in 3D playing the role of the central charge of matter in 2D.

hep-lat↗

arXiv1998

Three-dimensional simplicial gravity and combinatorics of group presentations

We demonstrate how some problems arising in simplicial quantum gravity can be successfully addressed within the framework of combinatorial group theory. In particular, we argue that the number of simplicial 3-manifolds having a fixed homology type grows exponentially with the number of tetrahedra they are made of. We propose a model of 3D gravity interacting with scalar fermions, some restriction of which gives the 2-dimensional self-avoiding-loop-gas matrix model. We propose a qualitative picture of the phase structure of 3D simplicial gravity compatible with the numerical experiments and available analytical results.

hep-th↗

arXiv1996

Quantum Deformation of Lattice Gauge Theory

A quantum deformation of 3-dimensional lattice gauge theory is defined by applying the Reshetikhin-Turaev functor to a Heegaard diagram associated to a given cell complex. In the root-of-unity case, the construction is carried out with a modular Hopf algebra. In the topological (weak-coupling) limit, the gauge theory partition function gives a 3-fold invariant, coinciding in the simplicial case with the Turaev-Viro one. We discuss bounded manifolds as well as links in manifolds. By a dimensional reduction, we obtain a q-deformed gauge theory on Riemann surfaces and find a connection with the algebraic Alekseev-Grosse-Schomerus approach.

hep-th↗

arXiv1995

One-dimensional dynamics of QCD2 string

We show that QCD$_2$ on 2D pseudo-manifolds is consistent with the Gross-Taylor string picture. It allows us to introduce a model describing the one-dimensional evolution of the QCD$_2$ string (in the sense that QCD$_2$ itself is regarded as a zero-dimensional system). The model is shown to possess the third order phase transition associated with the $c=1$ Bose string below which it becomes equivalent to the vortex-free sector of the 1-dimensional matrix model. We argue that it could serve as a toy model for the glueball-threshold behavior of multicolor QCD.

hep-th↗

arXiv1994

On Entropy of 3-Dimensional Simplicial Complexes

We prove that the number of 3-dimensional simplicial complexes having the spherical topology grows exponentially as a function of a volume. It is suggested that the 3d simplicial quantum gravity has qualitatively the same phase structure as the O(n) matrix model in the dense phase.

hep-th↗

arXiv1994

QCD on a Tree

A model is proposed which can be regarded as a mean field approximation for pure lattice QCD and chiral field. It always possesses a phase transition between a strong coupling phase (where it reduces to a one-plaquette integral) and a non-trivial weak coupling one. For the U(N) gauge group, it is equivalent to some multi-matrix model. This analogy allows for determining possible large N critical regimes thus generalizing the Gross-Witten phase transition in the one-plaquetee model.

hep-th↗

arXiv1993

3D Gravity and Gauge Theories

I argue that the complete partition function of 3D quantum gravity is given by a path integral over gauge-inequivalent manifolds times the Chern-Simons partition function. In a discrete version, it gives a sum over simplicial complexes weighted with the Turaev-Viro invariant. Then, I discuss how this invariant can be included in the general framework of lattice gauge theory (qQCD$_3$). To make sense of it, one needs a quantum analog of the Peter-Weyl theorem and an invariant measure, which are introduced explicitly. The consideration here is limited to the simplest and most interesting case of $SL_q(2)$, $q=e^{i\frac{2π}{k+2}}$. At the end, I dwell on 3D generalizations of matrix models.

hep-th↗

arXiv1993

Wilson loop on a sphere

We give the formula for a simple Wilson loop on a sphere which is valid for an arbitrary QCD$_2$ saddle-point $ρ(x)$: \mbox{$W(A_1,A_2)=\oint \frac{dx}{2πi} \exp(\int dy \frac{ρ(y)}{y-x}+A_2x)$}. The strong-coupling-phase solution is investigated.

hep-th↗

arXiv1992

Infinite Tension Strings at D>1

A matrix model describing surfaces embedded in a Bethe lattice is considered. From the mean field point of view, it is equivalent to the Kazakov-Migdal induced gauge theory and therefore, at $N=\infty$ and $d>1$, the latter can be interpreted as a matrix model for infinite-tension strings. We show that, in the naive continuum limit, it is governed by the one-matrix-model saddle point with an upside-down potential. To derive mean field equations, we consider the one-matrix model in external field. As a simple application, its explicit solution in the case of the inverted W potential is given.

hep-th↗

arXiv1992

q-deformed lattice gauge theory and 3-manifold invariants

The notion of $q$-deformed lattice gauge theory is introduced. If the deformation parameter is a root of unity, the weak coupling limit of a 3-$d$ partition function gives a topological invariant for a corresponding 3-manifold. It enables us to define the generalized Turaev-Viro invariant for cell complexes. It is shown that this invariant is determined by an action of a fundamental group on a universal covering of a complex. A connection with invariants of framed links in a manifold is also explored. A model giving a generating function of all simplicial complexes weighted with the invariant is investigated.

hep-th↗

arXiv1992

Local symmetry in the Kazakov-Migdal gauge model

The spectrum of observables in the induced lattice gauge model proposed recently by V.A.Kazakov and A.A.Migdal obeys the local-confinement selection rule. The underlying local continuous symmetry cannot be spontaneously broken within the model.

hep-th↗