Lorentz Violation in Emergent Gravity and Its Cosmological Consequences

Area of Science:

• Theoretical physics
• Cosmology
• Thermodynamics

Background:

• General relativity and geometrical theories are foundational in physics.
• The nature of emergent gravity and its relationship to established theories require further investigation.
• Cosmological acceleration presents a significant puzzle in modern astrophysics.

Purpose of the Study:

• To reframe geometrical theories, including general relativity, within a thermodynamic framework.
• To explore how thermodynamic cycles in emergent gravity can explain cosmological phenomena.
• To investigate the implications of these new theoretical insights for fundamental physics problems.

Main Methods:

• Modeling emergent gravity theories as a degenerate Otto cycle.
• Incorporating work-producing thermodynamic legs into the model.
• Analyzing the consequences of these modifications for physical principles like Lorentz invariance and energy-momentum conservation.

Main Results:

• General relativity and similar theories are shown to be a degenerate Otto cycle with only heat-exchange legs.
• The inclusion of work-producing legs results in controlled violations of local Lorentz invariance and energy-momentum conservation.
• These violations are demonstrated to be the source of late-time cosmological acceleration.

Conclusions:

• The Otto cycle provides a novel thermodynamic perspective on emergent gravity.
• Controlled violations of fundamental symmetries offer a potential explanation for cosmic acceleration.
• This framework has implications for the cosmological constant problem, structure formation, and local observational tests.