Stochastic Gravity: Theory and Applications

Hu, B. L.; Verdaguer, Enric

doi:10.12942/lrr-2008-3

Cited by 156 publications

(202 citation statements)

References 389 publications

(1,258 reference statements)

Supporting

Mentioning

192

Contrasting

Unclassified

Order By: Relevance

“…It should be emphasized that we are not referring to transition matrix elements but to the correlation functions appearing in the closed time path (also known as in-in), formalism [42,43,44,45,46]. They can be obtained either from a purely quantum field theoretical calculation [47] or within the framework of stochastic gravity [48,49,50,51,52], which provides an equivalent way of obtaining the result at order 1/N [53,54]. The Riemann tensor of the background de Sitter spacetime with appropriately raised indices is given by…”

Section: Discussionmentioning

confidence: 99%

Stress tensor fluctuations in de Sitter spacetime

Pérez-Nadal

Roura

Verdaguer

2010

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

The two-point function of the stress tensor operator of a quantum field in de Sitter spacetime is calculated for an arbitrary number of dimensions. We assume the field to be in the Bunch-Davies vacuum, and formulate our calculation in terms of de Sitter-invariant bitensors. Explicit results for free minimally coupled scalar fields with arbitrary mass are provided. We find long-range stress tensor correlations for sufficiently light fields (with mass m much smaller than the Hubble scale H), namely, the two-point function decays at large separations like an inverse power of the physical distance with an exponent proportional to m 2 /H 2 . In contrast, we show that for the massless case it decays at large separations like the fourth power of the physical distance. There is thus a discontinuity in the massless limit. As a byproduct of our work, we present a novel and simple geometric interpretation of de Sitter-invariant bitensors for pairs of points which cannot be connected by geodesics.

show abstract

Section: Discussionmentioning

confidence: 99%

Stress tensor fluctuations in de Sitter spacetime

Pérez-Nadal

Roura

Verdaguer

2010

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…[23]). One important theory in which this is done systematically from first principles is stochastic semiclassical gravity [24][25][26][27][28][29], or stochastic gravity in short, which takes into account fluctuations of the gravitational field that are induced by the quantum matter fields.…”

Section: Introductionmentioning

confidence: 99%

Noise kernel for a quantum field in Schwarzschild spacetime under the Gaussian approximation

et al. 2012

View full text Add to dashboard Cite

A method is given to compute an approximation to the noise kernel, defined as the symmetrized connected 2-point function of the stress tensor, for the conformally invariant scalar field in any spacetime conformal to an ultra-static spacetime for the case in which the field is in a thermal state at an arbitrary temperature. The most useful applications of the method are flat space where the approximation is exact and Schwarzschild spacetime where the approximation is better than it is in most other spacetimes. The two points are assumed to be separated in a timelike or spacelike direction. The method involves the use of a Gaussian approximation which is of the same type as that used by Page [1] to compute an approximate form of the stress tensor for this field in Schwarzschild spacetime. All components of the noise kernel have been computed exactly for hot flat space and one component is explicitly displayed. Several components have also been computed for Schwarzschild spacetime and again one component is explicitly displayed.

show abstract

“…If we extrapolate this example the stochastic gravity framework [91,92] might correspond to the continuous version of several discrete stochastic steps, e.g. the one given by the CSL dynamical collapse model.…”

Section: The Csl Model During Inflationmentioning

confidence: 99%

Eternal inflation and the quantum birth of cosmic structure

León

2017

Eur. Phys. J. C

View full text Add to dashboard Cite

We consider the eternal inflation scenario of the slow-roll/chaotic type with the additional element of an objective collapse of the wave function. The incorporation of this new agent to the traditional inflationary setting might represent a possible solution to the quantum measurement problem during inflation, a subject that has not reached a consensus among the community. Specifically, it could provide an explanation for the generation of the primordial anisotropies and inhomogeneities, starting from a perfectly symmetric background and invoking symmetric dynamics. We adopt the continuous spontaneous localization model, in the context of inflation, as the dynamical reduction mechanism that generates the primordial inhomogeneities. Furthermore, when enforcing the objective reduction mechanism, the condition for eternal inflation can be bypassed. In particular, the collapse mechanism incites the wave function, corresponding to the inflaton, to localize itself around the zero mode of the field. Then the zero mode will evolve essentially unperturbed, driving inflation to an end in any region of the Universe where inflation occurred. Also, our approach achieves a primordial spectrum with an amplitude and shape consistent with the one that best fits the observational data.

show abstract

Stochastic Gravity: Theory and Applications

Cited by 156 publications

References 389 publications

Stress tensor fluctuations in de Sitter spacetime

Stress tensor fluctuations in de Sitter spacetime

Noise kernel for a quantum field in Schwarzschild spacetime under the Gaussian approximation

Eternal inflation and the quantum birth of cosmic structure

Contact Info

Product

Resources

About