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Schwinger-Keldysh EFT · noise · rare events
Fluctuations, memory and non-equilibrium dynamics
We develop effective theories of fluctuations, memory and rare events in systems driven away from equilibrium. Schwinger-Keldysh methods let us connect dissipation to noise, test whether non-Gaussian stochastic sectors correspond to genuine positive probabilities, and keep track of memory when additional relaxation modes are resolved or integrated out.
Research questions
What we are trying to understand
Which non-Gaussian noise couplings are compatible with positive probability distributions and thermal KMS symmetry?
How does integrating out relaxation modes generate memory, coloured noise and scale-dependent stochastic transport?
How can effective theories describe rare events, Brownian motion and local detailed balance beyond the Gaussian hydrodynamic limit?
Programme strands
What is currently in this programme
- Positive stochastic completion and optimisation of non-Gaussian noise
- Spectral RG matching of positive-noise Schwinger-Keldysh EFTs
- Large deviations and contraction to macroscopic fluctuation theory
- Maxwell-Cattaneo memory, temperature and velocity modes
- Modified KMS / local detailed balance and Brownian-particle couplings
Why it matters
Impact and connections
The programme turns consistency conditions such as positivity, causality and KMS symmetry into quantitative constraints on stochastic dynamics. It links hydrodynamics to large-deviation theory, open-system dynamics and coarse graining while retaining explicit control of non-hydrodynamic memory.