A5091998602- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Quantum Mechanics and Applications
- Quantum and Classical Electrodynamics
- Astronomy and Astrophysical Research
- Quantum Information and Cryptography
University of Cambridge
2023-2024
A bstract Cosmological correlators from inflation are often generated at tree level and hence loop contributions bounded to be small corrections by perturbativity. Here we discuss a scenario where this is not the case. Recently, it has been shown that for any number of scalar fields mass, parity-odd trispectrum massless must vanish in limit exact scale invariance due unitarity choice initial state. By carefully handling UV-divergences, show one-loop contribution non-vanishing leading....
A bstract The squeezed limit of the primordial curvature bispectrum is an extremely sensitive probe new physics and encodes information about additional fields active during inflation such as their masses spins. In conventional setup, are stable with a positive mass squared, hence induce decreasing signal in limit, making detection challenging. Here we consider scalar field that temporarily unstable by virtue transient tachyonic mass, construct models which it embedded consistently within...
The squeezed limit of the primordial curvature bispectrum is an extremely sensitive probe new physics and encodes information about additional fields active during inflation such as their masses spins. In conventional setup, are stable with a positive mass squared, hence induce decreasing signal in limit, making detection challenging. Here we consider scalar field that temporarily unstable by virtue transient tachyonic mass, construct models which it embedded consistently within inflation....
Physical theories have a limited regime of validity and hence must be accompanied by breakdown diagnostic to establish when they cease valid as parameters are varied. For perturbative theories, estimates the first neglected order offer valuable guidance, but one is often interested in sharp bounds beyond which perturbation theory necessarily fails. In particle physics, it common employ on partial waves imposed unitarity such diagnostic. Unfortunately, these don't extend curved spacetime,...
Cosmological correlators from inflation are often generated at tree level and hence loop contributions bounded to be small corrections by perturbativity. Here we discuss a scenario where this is not the case. Recently, it has been shown that for any number of scalar fields mass, parity-odd trispectrum massless must vanish in limit exact scale invariance due unitarity choice initial state. By carefully handling UV-divergences, show one-loop contribution non-vanishing leading. Surprisingly,...