Quasiparticles, coherence and nonlinearity: exact simulations of RF-spectroscopy of strongly interacting one-dimensional Fermi gases

TL;DR

This paper uses exact simulations to analyze RF-spectroscopy in strongly interacting one-dimensional Fermi gases, revealing deviations from linear response and exploring the crossover between quasiparticle and coherent rotation descriptions, with implications for quantum measurement.

Contribution

It provides the first exact simulation-based analysis of RF-spectroscopy in 1D Fermi gases, highlighting deviations from sum rules and comparing different theoretical descriptions.

Findings

Deviations from linear response suppress pairing contributions.

RF-spectroscopy shows a crossover between quasiparticle and coherent rotation models.

Potential for studying decoherence in quantum measurement contexts.

Abstract

We consider RF-spectroscopy of ultracold Fermi gases by exact simulations of the many-body state and the coherent dynamics in one dimension. Deviations from the linear response sum rule result are found to suppress the pairing contribution to the RF line shifts. We compare the coherent rotation and quasiparticle descriptions of RF-spectroscopy which are analogous to NMR experiments in superfluid $^3$He and tunneling in solids, respectively. We suggest that RF-spectroscopy in ultracold gases provides an interesting crossover between these descriptions that could be used for studying decoherence in quantum measurement, in the context of many-body quantum states.