Observation of collective nonradiative coherence in potassium atoms with two-dimensional coherent spectroscopy
YiFeng Geng, ShaoGang Yu, YanZuo Chen +5 more
Quantum coherence of collective states plays a pivotal role in understanding many-body cooperative behaviors. Collective coherences between the ground state and excited states in potassium atoms were previously revealed; however, the coherence between collectively excited states has hitherto been overlooked, and its observation has remained challenging. Here we present a joint experimental and theoretical investigation of coherence effects in K atomic vapor using two-dimensional coherent spectroscopy. By collecting zero-quantum, double-quantum, and double-quantum--zero-quantum two-dimensional spectra, distinct coherence signatures are spectroscopically accessible. The experimental spectra are well reproduced by numerically solving the time dependence of the Lindblad equation, and further analyses unveil nonradiative coherence as the origin of the observations. Our work provides comprehensive insight into the collective coherence effect in multiatom systems.
Physical Review A•Jan 3, 2025•2 citations