Causality and Positivity with Gravity - Claudia de Rham

Explore the intersection of causality, positivity, and gravity in this conference talk from the Kavli Institute for Theoretical Physics' "UV Meets the IR" online conference. Delve into the complexities of effective field theories (EFTs) and their relationship with quantum gravity. Examine the implications of string theory's landscape and the swampland program on low-energy physics. Investigate bottom-up S-matrix techniques and their applications in bounding EFTs. Learn about recent developments in quantum field theory, including the modern on-shell amplitudes program and bootstrap methods. Follow the speaker's analysis of non-gravitational EFTs, the addition of gravity to these theories, and the resulting positivity bounds in gravitational low-energy effective field theories. Discover insights into scalar QED with gravity, compactified bounds, and approximate positivity. Explore the EFT for gravity, the speed of gravity, and support outside the light cone. Investigate QED on curved spacetime, time delays and advances, and the regime of validity for EFTs. Conclude by examining causality in gravitational theories, the concept of no support outside the light cone, and the implications of superluminality and negativity in these frameworks.

Intro
Non-Gravitational EFT
Adding Gravity?
Positivity Bounds in Gravitational LEEFT
Scalar QED with gravity
Compactified bounds & Scalar QED
Approximate Positivity
EFT for Gravity
Speed of Gravity
Support Outside Light-Cone
QED on curved spacetime
Time-delay/advance
Regime of Validity of EFT
Causality in Gravitational Theories
No support outside the light-cone
Living with Superluminality
Living with Negativity