Notes

Informal notes and derivations on topics in quantum dynamics, open quantum systems, spectroscopy, and related areas. These are mainly for my own reference but may be useful to others.

Selected topics

  • Linear spectra of a two-level system coupled to a harmonic bath

    Derivation of the linear absorption lineshape for a single two-level system linearly coupled to a harmonic bath, including Drude–Lorentz, underdamped Brownian, and combined spectral densities.

  • Reaction-coordinate mappings and Brownian spectral densities

    Sketches and derivations for mapping underdamped Brownian spectral densities to effective reaction coordinates plus residual baths.

  • PLDM and spin-mapping for open quantum systems

    Notes on path-integral derivations of PLDM and extensions to spin-mapping and Lindblad-type environments.

  • Green’s functions and linear response for exciton–polariton systems

    Working notes on relating retarded Green’s functions, self-energies, and linear spectra for Tavis–Cummings and generalized cavity models.