Quantum Fields and Extended Objects in Space-Times with Constant Curvature Spatial Section
A. A. Bytsenko, G. Cognola, L. Vanzo, S. Zerbini
TL;DR
The work analyzes quantum fields and extended objects in space-times with spatial sections of constant curvature, emphasizing ultrastatic manifolds. It develops and applies ζ-function regularization and heat-kernel techniques to compute one-loop determinants, vacuum energies, and finite-temperature potentials, including exact Selberg-trace-formula-based results on compact hyperbolic spaces. The authors extend these methods to strings and p-branes, deriving density-of-states asymptotics and examining Casimir energies and symmetry-breaking effects induced by topology and curvature. Finite-temperature analyses reveal rich thermodynamic structures, including Bose–Einstein condensation in hyperbolic spaces and curvature/topology-dependent phase behavior. Collectively, the paper provides a comprehensive framework for exact and semiclassical quantum analyses on curved backgrounds, with explicit results for toroidal, spherical, and hyperbolic geometries and for extended objects in such spaces.
Abstract
The heat-kernel expansion and $ζ$-regularization techniques for quantum field theory and extended objects on curved space-times are reviewed. In particular, ultrastatic space-times with spatial section consisting in manifold with constant curvature are discussed in detail. Several mathematical results, relevant to physical applications are presented, including exact solutions of the heat-kernel equation, a simple exposition of hyperbolic geometry and an elementary derivation of the Selberg trace formula. With regards to the physical applications, the vacuum energy for scalar fields, the one-loop renormalization of a self-interacting scalar field theory on a hyperbolic space-time, with a discussion on the topological symmetry breaking, the finite temperature effects and the Bose-Einstein condensation, are considered. Some attempts to generalize the results to extended objects are also presented, including some remarks on path integral quantization, asymptotic properties of extended objects and a novel representation for the one-loop (super)string free energy.
