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Title: Information content of gravitational radiation and the vacuum

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1328564
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 94; Journal Issue: 6; Related Information: CHORUS Timestamp: 2016-09-19 18:11:01; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Bousso, Raphael, Halpern, Illan, and Koeller, Jason. Information content of gravitational radiation and the vacuum. United States: N. p., 2016. Web. doi:10.1103/PhysRevD.94.064047.
Bousso, Raphael, Halpern, Illan, & Koeller, Jason. Information content of gravitational radiation and the vacuum. United States. doi:10.1103/PhysRevD.94.064047.
Bousso, Raphael, Halpern, Illan, and Koeller, Jason. 2016. "Information content of gravitational radiation and the vacuum". United States. doi:10.1103/PhysRevD.94.064047.
@article{osti_1328564,
title = {Information content of gravitational radiation and the vacuum},
author = {Bousso, Raphael and Halpern, Illan and Koeller, Jason},
abstractNote = {},
doi = {10.1103/PhysRevD.94.064047},
journal = {Physical Review D},
number = 6,
volume = 94,
place = {United States},
year = 2016,
month = 9
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevD.94.064047

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  • We introduce an approximation to calculate the gravitational radiation produced by the collision of true-vacuum bubbles that is simple enough to allow the simulation of a phase transition by the collision of hundreds of bubbles. This envelope approximation'' neglects the complicated overlap'' regions of colliding bubbles and follows only the evolution of the bubble walls. The approximation accurately reproduces previous results for the gravitational radiation from the collision of two scalar-field vacuum bubbles. Using a bubble nucleation rate given by [Gamma]=[Gamma][sub 0][ital e][sup [beta][ital t]], we simulate a phase transition by colliding 20 to 200 bubbles; the fraction of vacuummore » energy released into gravity waves is [ital E][sub GW]/[ital E][sub vac]=0.06([ital H]/[beta])[sup 2] and the peak of the spectrum occurs at [omega][sub max]=1.6[beta] ([ital H][sup 2]=8[pi][ital G][rho]/3 is the Hubble constant associated with the false-vacuum phase). The spectrum is very similar to that in the two-bubble case, except that the efficiency of gravity-wave generation is about five times higher, presumably due to the fact that a given bubble collides with many others. Finally, we consider two further statistical'' approximations, where the gravitational radiation is computed as an incoherent sum over individual bubbles weighted by the distribution of bubble sizes. These approximations provide reasonable estimates of the gravitational-wave spectrum with far less computation.« less
  • Generation of photons in a curved space-time due to polarization of the electron-positron vacuum is considered: R ..-->.. 2/sub ..gamma../. A general expression for the number of photon pairs is obtained, and the limits of its applicability are discussed.
  • Scattering and inelastic cross sections are calculated for gravitational radiation incident along the axis of symmetry of a vacuum black hole. We consider both nonrotating and rotating black holes and, in the latter case, both corotating and counterrotating circularly polarized incident radiation. Graphical results are displayed for the superradiance or absorption, the phase shifts, and the cross section for scattering of gravitational waves over a range of the parameter values of interest.
  • In the linearized-gravity approximation we numerically compute the amount of gravitational radiation produced by the collision of two true-vacuum bubbles in Minkowski space. The bubbles are separated by distance {ital d} and we calculate the amount of gravitational radiation that is produced in a time {tau}{similar to}{ital d} (in a cosmological phase transition {tau} corresponds to the duration of the transition, which is expected to be of the order of the mean bubble separation {ital d}). Our approximations are generally valid for {tau}{approx lt}{ital H}{sup {minus}1}. We find that the amount of gravitational radiation produced depends only upon the grossestmore » features of the collision: the time {tau} and the energy density associated with the false-vacuum state, {rho}{sub vac}. In particular, the spectrum {ital dE}{sub GW}/{ital d}{omega}{proportional to}{rho}{sub vac}{sup 2}{tau}{sup 6} and peaks at a characteristic frequency {omega}{sub max}{congruent}3.8/{tau}, and the fraction of the vacuum energy released into gravitational waves is about 1.3{times}10{sup {minus}3}({tau}/{ital H}{sup {minus}1}){sup 2}, where {ital H}{sup 2}=8{pi}{ital G}{rho}{sub vac}/3 ({tau}/{ital H}{sup {minus}1} is expected to be of the order of a few percent). We address in some detail the important symmetry issues in the problem, and how the familiar quadrupole approximation'' breaks down in a most unusual way: it {ital overestimates} the amount of gravitational radiation produced in this highly relativistic situation by more than a factor of 50. Most of our results are for collisions of bubbles of equal size, though we briefly consider the collision of vacuum bubbles of unequal size. Our work implies that the vacuum-bubble collisions associated with strongly first-order phase transition are a very potent cosmological source of gravitational radiation.« less