Event Details

Open physical systems with balanced loss and gain exhibit a transition, absent in their solitary counterparts, which engenders modes that exponentially decay or grow with time and thus spontaneously breaks the parity-time (PT) symmetry. Such PT-symmetric breaking transition has attracted many interests because its extraordinary behavior and functionalities lacking in the closed systems. Here we report on the observation of PT-symmetry breaking transitions with ultracold 6Li atoms by engineering static dissipative, Floquet dissipative, and Floquet coupling Hamiltonians through controlled, state-dependent atom loss in a noninteracting ultracold Fermi gas. While a single transition appears in the static case, we find that the Floquet counterpart undergoes PT-symmetry breaking and restoring transitions at vanishingly small dissipation strength in both single and multiphoton transitions domains, revealing rich band structures associated to Floquet modulations. These results enable ultracold atoms to be a versatile tool for studying novel physical phenomena in PT-symmetric quantum physics with many-body interaction.

Articles

- Observation of parity-time symmetry breaking transitions in a dissipative Floquet system of ultracold atoms, Jiaming Li, Andrew K. Harter, Ji Liu, Leonardo de Melo, Yogesh N. Joglekar, Le Luo, Nature Communications,10,855 (2019)
- Three-Body Recombination near a Narrow Feshbach Resonance in 6Li, Jiaming Li, Ji Liu, Le Luo, Bo Gao, Phys. Rev. Lett., 120, 193402 (2018)