Phase transitions in the early universe and their signals
Date:
April 19, 2022
Source:
University of Helsinki
Summary:
The early universe may chirp about unknown physics. A research team
has demonstrated how an early universe phase transition will lead
to gravitational wave signals potentially visible in the upcoming
satellite missions.
FULL STORY ==========================================================================
The early universe may chirp about unknown physics. A University of
Helsinki research team has demonstrated how an early universe phase
transition will lead to gravitational wave signals potentially visible
in the upcoming satellite missions. The research results were recently published in the journal Physical Review Letters.
========================================================================== Phase transitions, such as the boiling of water or the melting of a metal,
are commonplace but fascinating phenomena that spur surprises decades
after decades. They often occur as the temperature of a substance is
changed, through the nucleation of bubbles of the new phase which then
expands. In the end, the new phase has taken over the whole container.
The early universe was composed of a hot plasma whose temperature
decreased as the universe expanded. It is speculated by many physicists
that a phase transition may have occurred soon after the Big Bang. This
would then had lead to nucleation of bubbles and their subsequent
collisions. Such collisions would create powerful ripples in spacetime
which could be observed in planned gravitational wave detectors. The
Laser Interferometer Space Antenna (LISA), with a provisional launch
date in 2037, is one such probe that may be able to detect these early
Universe spacetime ripples.
However, to describe early universe phase transitions has been
challenging. The University of Helsinki researchers Oscar Henriksson,
Mark Hindmarsh, and Niko Jokela, together with colleagues at the U. of
Oviedo and the U. of Sussex, attacked this problem using a technique
from string theory known as holographic duality. They showed how the
duality can be used to map the problem to a more tractable one, and
how the important quantities describing the bubble nucleation and the associated gravitational wave signals can be extracted.
In the future these new methods can be applied directly in more realistic scenarios, where the starting point would be a possible extension of
Standard Model of particle physics.
The group is also tackling the remaining obstacle, the computation of the bubble wall velocity, needed for the full first principles description
of early universe phase transition and the imprint it makes on the gravitational wave spectrum.
========================================================================== Story Source: Materials provided by University_of_Helsinki. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Fe"anor Reuben Ares, Oscar Henriksson, Mark Hindmarsh, Carlos
Hoyos, Niko
Jokela. Gravitational Waves at Strong Coupling from an Effective
Action.
Physical Review Letters, 2022; 128 (13) DOI: 10.1103/
PhysRevLett.128.131101 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220419103208.htm
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