Quantum fluctuations of vacuum stress tensors and spacetime curvatures

Stress-Energy in the Conical Vacuum and its Implications for Topology Change

This dissertation presents a semiclassical analysis of conical topology change in $1+1$ spacetime dimensions wherein, to lowest order, the ambient spacetime is classical and fixed while the scalar field coupled to it is quantized. The vacuum expectation value of the scalar field stress-energy tensor is calculated via two different approaches. The first of these involves the explicit determination of the so called Sorkin-Johnston state on the cone and an original regularization scheme, while the latter employs the conformal vacuum and the more conventional point-splitting renormalization. It is…

Quantum Vacuum Heuristics

Didactic heuristic arguments, based on the quantum mechanics of the vacuum and the structure of spacetime, are reviewed concerning particle creation from the vacuum by an electric field, vacuum radiation in an accelerated frame, black-hole radiation, minimum-mass black holes, spacetime breakdown, maximal proper acceleration, the spacetime tangent bundle, and intrinsic Planck-scale regularization of quantum fields.

Vacuum currents in partially compactified Rindler spacetime with an application to cylindrical black holes

The vacuum expectation value of the current density for a charged scalar field is investigated in Rindler spacetime with a part of spatial dimensions compactified to a torus. It is assumed that the field is prepared in the Fulling-Rindler vacuum state. For general values of the phases in the periodicity conditions and the lengths of compact dimensions, the expressions are provided for the Hadamard function and vacuum currents. The current density along compact dimensions is a periodic function of the magnetic flux enclosed by those dimensions and vanishes on the Rindler horizon. The obtained r…

Reissner-Nordström时空中Hartle-Hawking态、Boulware态与Unruh态下标量场的重整化应力-能量张量

Renormalized stress-energy tensor for scalar fields in Hartle-Hawking, Boulware and Unruh states in the Reissner-Nordström spacetime

本文针对Reissner-Nordström时空中的量子标量场，用扩展坐标方案重整化Hartle-Hawking态的应力-能量张量，再利用态间差有限的性质得到Boulware态和Unruh态的结果，覆盖多组场与黑洞参数并与文献解析近似对比。

Vacuum polarization induced by a cylindrical boundary in the cosmic string spacetime

In this paper we investigate the Wightman function, the renormalized vacuum expectation values of the field square, and the energy-momentum tensor for a massive scalar field with general curvature coupling inside and outside of a cylindrical shell in the generalized spacetime of straight cosmic string. For the general case of Robin boundary condition, by using the generalized Abel-Plana formula, the vacuum expectation values are presented in the form of the sum of boundary-free and boundary-induced parts. The asymptotic behavior of the vacuum expectation values of the field square, energy dens…

Vacuum polarization by a flat boundary in cosmic string spacetime

In this paper we analyze the vacuum expectation values of the field squared and the energy-momentum tensor associated to a massive scalar field in a higher dimensional cosmic string spacetime, obeying Dirichlet or Neumann boundary conditions on the surface orthogonal to the string. In order to develop this analysis the corresponding Green function is obtained. The Green function is given by the sum of two expressions: the first one corresponds to the standard Green function in the boundary-free cosmic string spacetime and the second contribution is induced by the boundary. The boundary induced…

德西特时空中宇宙弦周围的真空极化

Vacuum polarization around cosmic strings in de Sitter spacetime

该研究以德西特时空为背景，分析平直宇宙弦与引力场对三类量子真空局域性质的共同作用，发现曲率在大距离下影响显著，且存在径向真空能流这一新特征。

Surface vacuum energy and stresses on a plate uniformly accelerated through the Fulling-Rindler vacuum

The vacuum expectation value of the surface energy-momentum tensor is evaluated for a massless scalar field obeying mixed boundary condition on an infinite plate moving by uniform proper acceleration through the Fulling-Rindler vacuum. The generalized zeta function technique is used, in combination with the contour integral representation. The surface energies for separate regions on the left and on the right of the plate contain pole and finite contributions. Analytic expressions for both these contributions are derived. For a minimally coupled scalar the surface energy-momentum tensor induce…

Casimir densities for a boundary in Robertson-Walker spacetime

For scalar and electromagnetic fields we evaluate the vacuum expectation value of the energy-momentum tensor induced by a curved boundary in the Robertson--Walker spacetime with negative spatial curvature. In order to generate the vacuum densities we use the conformal relation between the Robertson-Walker and Rindler spacetimes and the corresponding results for a plate moving by uniform proper acceleration through the Fulling--Rindler vacuum. For the general case of the scale factor the vacuum energy-momentum tensor is presented as the sum of the boundary free and boundary induced parts.