Abstract
Non-Hermitian spin-orbit-coupled fermions provide a powerful platform for exploring exotic quantum phenomena in dissipative quantum systems, extending beyond conventional closed quantum systems described by Hermitian Hamiltonians. Using ultracold fermions 173Y b with a high nuclear spin (I = 5/2), we develop a versatile non-Hermitian spinorbit-coupled fermionic system. This allows us to study high-order exceptional points and explore the interplay between non-Hermitian physics and engineering protocols, including floquet-driven topology and photoassociation.
First, we outline the advantages of the ytterbium element and describe the structure of a dedicated ytterbium apparatus, integrating ultrahigh vacuum, stabilized lasers, and the computer-based control system to achieve quantum degeneracy and suppress thermal noise. Advanced imaging techniques, including time-of-flight expansion and the quantum gas magnifier, are employed to probe momentum and real distributions. Additionally, we have progressively advanced the development of the quantum gas microscope with the optical transport and preliminary preparations accomplished.
Turning to the non-Hermitian studies, we demonstrate third-order exceptional points in non-Hermitian spin-orbit-coupled fermions, where three states coalesce, exhibiting cubic-root response scaling and distinct dynamical encircling behaviors compared to conventional second-order exceptional points. Using floquet driving in a dissipative optical raman lattice, we generate novel non-Hermitian topological bands and engineer quantum phases in the floquet brillouin zone.
The fermionic nature of 173Y b fundamentally alters photochemical reactions compared to bosonic systems with pauli exclusion and decoherence imposing unique constraints on quantum coherent control. Photoassociation of fermions dressed by spin-orbit coupling facilitates the understanding of mechanism of the two-body loss, which drives the non-Hermitian system from the non-interacting regime to the interacting regime.
These results establish non-Hermitian spin-orbit-coupled fermions as a rich testbed for exploring open quantum systems. The different approaches including high-dimensional spin systems, floquet driving, and tunable two-body loss open new avenues for quantum simulation of complex quantum phenomena.