Gravitational Waves at Strong Coupling from an Effective Action

Area of Science:

• High-energy physics
• Cosmology
• Gravitational wave astronomy

Background:

• First-order phase transitions are crucial cosmological events.
• Holographic duality provides a framework to study strongly coupled quantum field theories.
• Gravitational waves from such transitions offer a window into the early universe.

Purpose of the Study:

• To compute quasiequilibrium parameters for gravitational wave signals from a first-order phase transition.
• To explore the dependence of phase transition parameters on the effective degrees of freedom in a dual field theory.
• To assess the potential for detecting these signals with future observatories like LISA.

Main Methods:

• Holographic derivation of a quantum effective action for a scalar operator at strong coupling.
• Calculation of quasiequilibrium parameters relevant to gravitational wave emission.
• Analysis of phase transition parameters as a function of the dual field theory's degrees of freedom.

Main Results:

• The study provides a method to calculate key parameters for gravitational wave signals from strongly coupled first-order phase transitions.
• Phase transition characteristics are shown to vary with the effective number of degrees of freedom.
• An observable gravitational wave signal is possible at LISA for a critical temperature around a TeV, within a specific parameter regime.

Conclusions:

• The holographic approach offers a viable method for studying early universe phase transitions and their gravitational wave signatures.
• The findings suggest that future gravitational wave detectors could probe fundamental physics at TeV scales.
• Approximate conformal symmetry in the dual field theory plays a role in producing observable signals.