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Finite Bubble Statistics Constrain Late Cosmological Phase Transitions
Gilly Elor1, Ryusuke Jinno2,3, Soubhik Kumar4,5,6
1Weinberg Institute, Department of Physics, <a href="https://ror.org/00hj54h04">University of Texas at Austin</a>, Austin, Texas 78712, USA.
Physical Review Letters
|December 6, 2024
Summary
This study explores cosmic phase transitions, revealing how bubble nucleation fluctuations generate universal curvature fluctuations. These findings constrain dark-sector phase transitions, offering stronger limits than current neutrino measurements.
Area of Science:
- Cosmology
- Particle Physics
- Astrophysics
Background:
- Late-time first-order cosmological phase transitions (PTs) occur below standard model temperatures.
- Stochastic bubble nucleation in these PTs creates superhorizon fluctuations in completion time.
Purpose of the Study:
- To compute how these fluctuations source universal curvature fluctuations.
- To constrain the energy released in dark-sector PTs using observational data.
Main Methods:
- Analyzing superhorizon fluctuations from stochastic bubble nucleation.
- Utilizing cosmic microwave background (CMB) and large scale structure measurements for constraints.
- Comparing derived constraints with existing bounds (e.g., ΔNeff) and future projections (e.g., CMB-S4).
Main Results:
- Fluctuations in PT completion time universally source curvature fluctuations.
- Constraints on dark-sector PT energy release are derived for temperatures 0.1 eV≲T_{PT}≲keV.
- These constraints are more stringent than current ΔNeff bounds and some CMB-S4 projections.
Conclusions:
- The study provides a novel method to probe early universe physics through gravitational effects.
- Future CMB spectral distortions and pulsar timing arrays will offer competitive sensitivity for higher PT temperatures (keV≲T_{PT}≲GeV).
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