arXiv subjects

Aleksandar Bogojevic

Publications and source records attributed to Aleksandar Bogojevic.

27 records · Page 2Linked to original sources

arXiv2005

Jaggedness of Path Integral Trajectories

We define and investigate the properties of the jaggedness of path integral trajectories. The new quantity is shown to be scale invariant and to satisfy a self-averaging property. Jaggedness allows for a classification of path integral trajectories according to their relevance. We show that in the continuum limit the only paths that are not of measure zero are those with jaggedness 1/2, i.e. belonging to the same equivalence class as random walks. The set of relevant trajectories is thus narrowed down to a specific subset of non-differentiable paths. For numerical calculations, we show that jaggedness represents an important practical criterion for assessing the quality of trajectory generating algorithms. We illustrate the obtained results with Monte Carlo simulations of several different models.

cond-mat.stat-mech↗

arXiv2005

Systematically Accelerated Convergence of Path Integrals

We present a new analytical method that systematically improves the convergence of path integrals of a generic $N$-fold discretized theory. Using it we calculate the effective actions $S^{(p)}$ for $p\le 9$ which lead to the same continuum amplitudes as the starting action, but that converge to that continuum limit as $1/N^p$. We checked this derived speedup in convergence by performing Monte Carlo simulations on several different models.

cond-mat.stat-mech↗

arXiv1998

Wick Rotation and Abelian Bosonization

We investigate the connection between Abelian bosonization in the Minkowski and Euclidean formalisms. The relation is best seen in the complex time formalism of S. A. Fulling and S. N. M. Ruijsenaars \cite{fulling}.

hep-th↗

arXiv1998

Black Holes Without Singularities

We study the properties of a completely integrable deformation of the CGHS dilaton gravity model in two dimensions. The solution is shown to represent a singularity free black hole that at large distances asymptoticaly joins to the CGHS solution.

gr-qc↗

arXiv1998

The Role of Conformal Symmetry in Abelian Bosonization of the Massive Thirring Model

We show equivalence between the massive Thirring model and the sine-Gordon theory by gauge fixing a wider gauge invariant theory in two different ways. The exact derivation of the equivalence hinges on the existence of an underlying conformal symmetry. Previous derivations were all perturbative in mass (althought to all orders).

hep-th↗

arXiv1998

The Measure from Schwinger-Dyson Equations

We review a new prescription for calculating the Lagrangian path integral measure directly from the Hamiltonian Schwinger-Dyson equations. The method agrees with the usual way of deriving the measure in which one has to perform the path integration over momenta.

hep-th↗

arXiv1998

Improved Gaussian Approximation

In a recently developed approximation technique for quantum field theory the standard one-loop result is used as a seed for a recursive formula that gives a sequence of improved Gaussian approximations for the generating functional. In this paper we work with the generic $ϕ^3+ϕ^4$ model in $d=0$ dimensions. We compare the first, and simplest, approximation in the above sequence with the one-loop and two-loop approximations, as well as the exact results (calculated numericaly).

hep-th↗

arXiv1998

An Improved Gaussian Approximation for Quantum Field Theory

We present a new approximation technique for quantum field theory. The standard one-loop result is used as a seed for a recursive formula that gives a sequence of improved Gaussian approximations for the generating functional. In a different setting, the basic idea of this recursive scheme is used in the second part of the paper to substantialy speed up the standard Monte Carlo algorithm.

hep-th↗

arXiv1998

A Non-Singular Black Hole

We present a completely integrable deformation of the CGHS dilaton gravity model in two dimensions. The solution is a singularity free black hole that at large distances asymptoticaly joins to the CGHS solution.

gr-qc↗