• Phase transitions in the early universe

    From ScienceDaily@1:317/3 to All on Tue Apr 19 22:30:44 2022
    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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