Results 1 
2 of
2
Stochastic gravity: Theory and applications
 Living Rev. Relativ
, 2004
"... Stochastic semiclassical gravity of the 90’s is a theory naturally evolved from semiclassical gravity of the 80’s and quantum field theory in curved spacetimes of the 70’s. Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of th ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
Stochastic semiclassical gravity of the 90’s is a theory naturally evolved from semiclassical gravity of the 80’s and quantum field theory in curved spacetimes of the 70’s. Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stressenergy tensor of quantum fields, stochastic semiclassical gravity is based on the EinsteinLangevin equation, which has in addition sources due to the noise kernel. The noise kernel is the vacuum expectation value of the (operatorvalued) stressenergy bitensor which describes the fluctuations of quantum matter fields in curved spacetimes. A new criterion for the validity of semiclassical gravity may also be formulated from the viewpoint of this theory. In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. The axiomatic approach is useful to see the structure of the theory from the framework of semiclassical gravity, showing the link from the mean value of the stressenergy tensor to their correlation functions. The functional approach uses the FeynmanVernon influence functional and the SchwingerKeldysh closedtimepath effective action methods which are convenient for computations. It also brings out the open systems concepts and the statistical
SmallScale Structure of Spacetime: Bounds and Conjectures
, 710
"... Abstract. This review consists of two parts. The first part establishes certain astrophysical bounds on the smoothness of classical spacetime. Some of the best bounds to date are based on the absence of vacuum Cherenkov radiation in ultrahighenergy cosmic rays. The second part discusses possible im ..."
Abstract
 Add to MetaCart
Abstract. This review consists of two parts. The first part establishes certain astrophysical bounds on the smoothness of classical spacetime. Some of the best bounds to date are based on the absence of vacuum Cherenkov radiation in ultrahighenergy cosmic rays. The second part discusses possible implications for the quantum structure of spacetime. A conjecture is presented that the fundamental length scale of quantum spacetime may be different from the Planck length.