Causality Constraints on Gravitational Effective Field Theories

Area of Science:

• Theoretical Physics
• Black Hole Physics
• Quantum Gravity

Background:

• Effective field theories describe gravity near black holes.
• Previous studies derived causality and positivity bounds.

Purpose of the Study:

• To investigate causality constraints on dimension-8 operators in gravity around black holes.
• To establish conditions for observable gravitational effects while preserving causality.

Main Methods:

• Analysis of effective field theory of gravity.
• Application of causality considerations to constrain operator coefficients.
• Distinguishing between "infrared causality" and "asymptotic causality".

Main Results:

• Dimension-8 operator coefficients are tightly constrained by causality.
• These constraints are tighter than previously known bounds.
• One specific dimension-8 operator's effects are unobservable alone under causality.
• A regime for potentially observable lower-order operators is identified.

Conclusions:

• Causality provides stringent limitations on gravitational theories around black holes.
• "Infrared causality" is crucial for accurately diagnosing causality violations.
• The findings offer a theoretical prior for future observational constraints on gravity.