Interacting non-Hermitian ultracold atoms in a harmonic trap:Two-body exact solution and a high-order exceptional point

摘要

We study interacting ultracold atoms in a three-dimensional (3D) harmonic trap with spin-selective dissipations,which can be effectively described by non-Hermitian parity-time (PT ) symmetric Hamiltonians.By exactly solving the non-Hermitian two-body problem of spin-1/2 (spin-1) bosons in a 3D harmonic trap,we find that the system can exhibit third-order (fifth-order) exceptional points (EPs) with ultrasensitive cube-root (fifth-root) spectral response due to interaction anisotropies in spin channels.We also present the general principle for the creation of high-order EPs and their spectral sensitivities with arbitrary particle number N and arbitrary spin s.Generally,with spin-independent interactions,the EP order of bosons can be as high as 2Ns + 1,and the spectral response around EP can be as sensitive as ~ε~(1/(2ks+1)) under a k-body interaction anisotropy.Moreover,we propose to detect the ultrasensitive spectral response through the probability dynamics of certain state.These results suggest a convenient route towards more powerful sensor devices in spinor cold atomic systems.