Ren Zhang

Oct 1, 2024 | link.aps.org | Chenwei Lv |Ren Zhang |Xi'an Jiaotong |Qi Zhou

Krylov complexity has emerged as a probe of operator growth in a wide range of nonequilibrium quantum dynamics. However, a fundamental issue remains in such studies: the definition of the distance between basis states in Krylov space is ambiguous. Here we show that Krylov complexity can be rigorously established from circuit complexity when dynamical symmetries exist.

Jun 21, 2023 | link.aps.org | Xiaoyi Yang |Quantum Optoelectronic Devices |Xi'an Jiaotong |Ren Zhang

Abstract Using high-temperature virial expansion, we study the quench dynamics of the thermal Bose gases near wide, narrow, and intermediate Feshbach resonances. Our results show that the shallow bound state near Feshbach resonances leads to oscillation of n̂k. Near the wide Feshbach resonance, the long-time momentum distribution n̂k oscillates when the scattering length as is quenched to large but with finite positive values. The oscillation frequency is determined by the bound-state energy.