scholarly journals Theoretical uncertainties for cosmological first-order phase transitions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Djuna Croon ◽  
Oliver Gould ◽  
Philipp Schicho ◽  
Tuomas V. I. Tenkanen ◽  
Graham White
Keyword(s):  
Phase Transitions ◽  
Standard Model ◽  
Scale Dependence ◽  
Effective Field ◽  
Bubble Nucleation ◽  
Perturbative Approach ◽  
First Order ◽  
The Standard Model ◽  
First Order Phase ◽  
Renormalisation Scale

Abstract We critically examine the magnitude of theoretical uncertainties in perturbative calculations of fist-order phase transitions, using the Standard Model effective field theory as our guide. In the usual daisy-resummed approach, we find large uncertainties due to renormalisation scale dependence, which amount to two to three orders-of-magnitude uncertainty in the peak gravitational wave amplitude, relevant to experiments such as LISA. Alternatively, utilising dimensional reduction in a more sophisticated perturbative approach drastically reduces this scale dependence, pushing it to higher orders. Further, this approach resolves other thorny problems with daisy resummation: it is gauge invariant which is explicitly demonstrated for the Standard Model, and avoids an uncontrolled derivative expansion in the bubble nucleation rate.

scholarly journals On the perturbative expansion at high temperature and implications for cosmological phase transitions

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Oliver Gould ◽  
Tuomas V. I. Tenkanen
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
Effective Potential ◽  
Bubble Nucleation ◽  
Perturbative Expansion ◽  
Zero Temperature ◽  
Loop Order ◽  
First Order ◽  
First Order Phase ◽  
Renormalisation Scale

Abstract We revisit the perturbative expansion at high temperature and investigate its convergence by inspecting the renormalisation scale dependence of the effective potential. Although at zero temperature the renormalisation group improved effective potential is scale independent at one-loop, we show how this breaks down at high temperature, due to the misalignment of loop and coupling expansions. Following this, we show how one can recover renormalisation scale independence at high temperature, and that it requires computations at two-loop order. We demonstrate how this resolves some of the huge theoretical uncertainties in the gravitational wave signal of first-order phase transitions, though uncertainties remain stemming from the computation of the bubble nucleation rate.

scholarly journals Phase transitions in the early universe

2021 ◽  
Author(s):  
Mark Hindmarsh ◽  
Marvin Lüben ◽  
Johannes Lumma ◽  
Martin Pauly
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Standard Model ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Early Universe ◽  
Order Approximation ◽  
First Order ◽  
The Standard Model ◽  
First Order Phase

These lecture notes are based on a course given by Mark Hindmarsh at the 24th Saalburg Summer School 2018 and written up by Marvin Lüben, Johannes Lumma and Martin Pauly. The aim is to provide the necessary basics to understand first-order phase transitions in the early universe, to outline how they leave imprints in gravitational waves, and advertise how those gravitational waves could be detected in the future. A first-order phase transition at the electroweak scale is a prediction of many theories beyond the Standard Model, and is also motivated as an ingredient of some theories attempting to provide an explanation for the matter-antimatter asymmetry in our Universe. Starting from bosonic and fermionic statistics, we derive Boltzmann's equation and generalise to a fluid of particles with field dependent mass. We introduce the thermal effective potential for the field in its lowest order approximation, discuss the transition to the Higgs phase in the Standard Model and beyond, and compute the probability for the field to cross a potential barrier. After these preliminaries, we provide a hydrodynamical description of first-order phase transitions as it is appropriate for describing the early Universe. We thereby discuss the key quantities characterising a phase transition, and how they are imprinted in the gravitational wave power spectrum that might be detectable by the space-based gravitational wave detector LISA in the 2030s.

scholarly journals Cosmological phase transitions: is effective field theory just a toy?

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Marieke Postma ◽  
Graham White
Keyword(s):  
Field Theory ◽  
Phase Transition ◽  
Phase Transitions ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Tree Level ◽  
Dark Sector ◽  
First Order ◽  
First Order Phase

Abstract To obtain a first order phase transition requires large new physics corrections to the Standard Model (SM) Higgs potential. This implies that the scale of new physics is relatively low, raising the question whether an effective field theory (EFT) description can be used to analyse the phase transition in a (nearly) model-independent way. We show analytically and numerically that first order phase transitions in perturbative extensions of the SM cannot be described by the SM-EFT. The exception are Higgs-singlet extension with tree-level matching; but even in this case the SM-EFT can only capture part of the full parameter space, and if truncated at dim-6 operators, the description is at most qualitative. We also comment on the applicability of EFT techniques to dark sector phase transitions.

scholarly journals Limiting first-order phase transitions in dark gauge sectors from gravitational waves experiments

2017 ◽  
Vol 32 (08) ◽  
pp. 1750049 ◽  
Author(s):  
Andrea Addazi
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Standard Model ◽  
Gravitational Waves ◽  
Parameter Space ◽  
Higgs Potential ◽  
Electroweak Phase Transition ◽  
First Order ◽  
First Order Phase

We discuss the possibility to indirectly test first-order phase transitions of hidden sectors. We study the interesting example of a Dark Standard Model (D-SM) with a deformed parameter space in the Higgs potential. A dark electroweak phase transition can be limited from next future experiments like eLISA and DECIGO.

scholarly journals Field-theoretic derivation of bubble-wall force

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Marc Barroso Mancha ◽  
Tomislav Prokopec ◽  
Bogumiła Świeżewska
Keyword(s):  
Standard Model ◽  
Lorentz Factor ◽  
Momentum Tensor ◽  
Active Species ◽  
Local Thermal Equilibrium ◽  
First Order ◽  
Opposite Case ◽  
First Order Phase Transition ◽  
The Standard Model ◽  
First Order Phase

Abstract We derive a general quantum field theoretic formula for the force acting on expanding bubbles of a first order phase transition in the early Universe setting. In the thermodynamic limit the force is proportional to the entropy increase across the bubble of active species that exert a force on the bubble interface. When local thermal equilibrium is attained, we find a strong friction force which grows as the Lorentz factor squared, such that the bubbles quickly reach stationary state and cannot run away. We also study an opposite case when scatterings are negligible across the wall (ballistic limit), finding that the force saturates for moderate Lorentz factors thus allowing for a runaway behavior. We apply our formalism to a massive real scalar field, the standard model and its simple portal extension. For completeness, we also present a derivation of the renormalized, one-loop, thermal energy-momentum tensor for the standard model and demonstrate its gauge independence.

Bubble nucleation rates in first-order phase transitions

1993 ◽  
Vol 48 (10) ◽  
pp. 6788-6794 ◽  
Author(s):  
W. N. Cottingham ◽  
D. Kalafatis ◽  
R. Vinh Mau
Keyword(s):  
Phase Transitions ◽  
Bubble Nucleation ◽  
First Order ◽  
First Order Phase

scholarly journals Bubble-nucleation rates for radiatively induced first-order phase transitions

1999 ◽  
Vol 554 (3) ◽  
pp. 697-718 ◽  
Author(s):  
Alessandro Strumia ◽  
Nikolaos Tetradis
Keyword(s):  
Phase Transitions ◽  
Bubble Nucleation ◽  
First Order ◽  
First Order Phase

scholarly journals Avoided deconfinement in Randall-Sundrum models

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Prateek Agrawal ◽  
Michael Nee
Keyword(s):  
Phase Transitions ◽  
Early Universe ◽  
Transition Rate ◽  
Gauge Theories ◽  
Scalar Fields ◽  
Effective Field ◽  
First Order ◽  
Restoration Mechanism ◽  
First Order Phase ◽  
Very High

Abstract We study first order phase transitions in Randall-Sundrum models in the early universe dual to confinement in large-N gauge theories. The transition rate to the confined phase is suppressed by a factor exp(−N2), and may not complete for N » 1, instead leading to an eternally inflating phase. To avoid this fate, the resulting constraint on N makes the RS effective field theory only marginally under control. We present a mechanism where the IR brane remains stabilized at very high temperature, so that the theory stays in the confined phase at all times after inflation and reheating. We call this mechanism avoided deconfinement. The mechanism involves adding new scalar fields on the IR brane which provide a stablilizing contribution to the radion potential at finite temperature, in a spirit similar to Weinberg’s symmetry non-restoration mechanism. Avoided deconfinement allows for a viable cosmology for theories with parametrically large N. Early universe cosmological phenomena such as WIMP freeze-out, axion abundance, baryogenesis, phase transitions, and gravitational wave signatures are qualitatively modified.

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