Speaker
Description
We formulate the two-color SUPER excitation scheme for a two-level emitter within the input-output theory for quantum pulses. This provides a mode-resolved quantum description of the experimental case of two coherent traveling pulses and allows direct comparison with previous cavity-based analyses. We show that the traveling-pulse realization retains the same multiphoton character as the cavity SUPER mechanism, visible as a net photon-number change of $-2$ in one mode and $+1$ in the other. At the same time, the pulse description is not equivalent to a two-mode cavity model: a minimum pulse photon number is required to achieve high-fidelity inversion. The system also serves as a useful testbed to showcase and compare several complementary methods to solve the dynamics. To treat the large coherent-state occupations relevant for SUPER, we combine the input-output formalism with a cumulant expansion approach. With an interaction-picture formulation the few exchanged photons that govern the nontrivial dynamics enable direct full-quantum calculations in truncated Hilbert spaces, including treatments in a displacement frame and for initial Fock-state pulses.