10-1103-PhysRevD-92-123009.pdf (1.25 MB)
Numerical simulations of acoustically generated gravitational waves at a first order phase transition
journal contribution
posted on 2023-06-09, 04:46 authored by Mark HindmarshMark Hindmarsh, Stephan HuberStephan Huber, Kari Rummukainen, David J WeirWe present details of numerical simulations of the gravitational radiation produced by a first order thermal phase transition in the early Universe. We confirm that the dominant source of gravitational waves is sound waves generated by the expanding bubbles of the low-temperature phase. We demonstrate that the sound waves have a power spectrum with a power-law form between the scales set by the average bubble separation (which sets the length scale of the fluid flow Lf) and the bubble wall width. The sound waves generate gravitational waves whose power spectrum also has a power-law form, at a rate proportional to Lf and the square of the fluid kinetic energy density. We identify a dimensionless parameter ˜ OGW characterizing the efficiency of this “acoustic” gravitational wave production whose value is 8p ˜ OGW?0.8±0.1 across all our simulations. We compare the acoustic gravitational waves with the standard prediction from the envelope approximation. Not only is the power spectrum steeper (apart from an initial transient) but the gravitational wave energy density is generically larger by the ratio of the Hubble time to the phase transition duration, which can be 2 orders of magnitude or more in a typical first order electroweak phase transition.
Funding
Particle Physics Theory at Royal Holloway and Sussex; G0742; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/J000477/1
History
Publication status
- Published
File Version
- Published version
Journal
Physical Review DISSN
2470-0010Publisher
American Physical SocietyExternal DOI
Issue
12Volume
92Page range
1-22Article number
a123009Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Theoretical Particle Physics Research Group Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2017-01-17First Open Access (FOA) Date
2017-01-17First Compliant Deposit (FCD) Date
2017-01-17Usage metrics
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