| Speaker: | Isaac Layton (University College London) |
|---|---|
| Title: | Classical-quantum dynamics and classical-quantum gravity |
| Date (JST): | Thu, Feb 08, 2024, 16:00 - 17:30 |
| Place: | Online |
| Abstract: |
If gravity were to be fundamentally classical, how would we describe the backreaction of quantum fields on spacetime? Conversely, if gravity is quantum mechanical as expected, when and how can we approximate spacetime as effectively classical while treating matter quantum mechanically? In this talk I introduce the formalism of classical-quantum dynamics, which provides a rigorous framework for studying consistent models of quantum backreaction on (effectively) classical systems. The new feature of these models, compared to traditional treatments such as the semi-classical Einstein equations, is that the evolution laws are stochastic. Using simple toy models, I will illustrate the core feature that distinguishes these systems experimentally, known as the decoherence-diffusion trade-off, and discuss how effective classical-quantum models can be derived as double scaling classical limits of a full quantum theory. Finally, I will discuss the application of this formalism to gravity as a fundamental theory, and the question of constructing effective classical-quantum models to describe vacuum fluctuations in cosmology. |
| Remarks: | Online APEC seminar Please join the zoom. |
