Spin-squeezed state is a many-body entangled state of great interest for precision measurements.Although the absolute sensitivity at the standard quantum limit is better for a larger atom number,the greater dominance ...Spin-squeezed state is a many-body entangled state of great interest for precision measurements.Although the absolute sensitivity at the standard quantum limit is better for a larger atom number,the greater dominance of classical noises over atom projection noise makes it harder to achieve spin squeezing.Here,we show both theoretically and experimentally that adiabatic pulse control of the pump field in state preparation is indispensable to sufficient noise suppression,which is the prerequisite for spin squeezing.This technique is generally applicable to spin-squeezing experiments involving a large ensemble and is thus of significance for quantum metrolog yapplications.展开更多
We experimentally demonstrate tunable non-Hermitian coupling in an atomic-vapor cell where atomic coherences in different optical channels are dissipatively coupled through atomic motion.Introducing a far-detuned ligh...We experimentally demonstrate tunable non-Hermitian coupling in an atomic-vapor cell where atomic coherences in different optical channels are dissipatively coupled through atomic motion.Introducing a far-detuned light wall in the reservoir between the optical channels,we decorate the inter-channel coupling term so that it can be switched from dissipative to coherent.The tunable non-Hermiticity is then confirmed through measurements of the inter-channel light transport where the light-wall-induced phase shift is directly probed.Based on the tunable non-Hermiticity,we further discuss an exemplary scheme in which our setup can serve as a building block for the experimental study of exotic non-Hermitian criticality.展开更多
基金National Key Research and Development Program of China(2017YFA0304204,2016YFA0302000)National Natural Science Foundation of China(12027806,91636107)+2 种基金Royal Society Newton International Fellowship(NF170876)PCSIRT(IRT_17R70)1331KSC。
文摘Spin-squeezed state is a many-body entangled state of great interest for precision measurements.Although the absolute sensitivity at the standard quantum limit is better for a larger atom number,the greater dominance of classical noises over atom projection noise makes it harder to achieve spin squeezing.Here,we show both theoretically and experimentally that adiabatic pulse control of the pump field in state preparation is indispensable to sufficient noise suppression,which is the prerequisite for spin squeezing.This technique is generally applicable to spin-squeezing experiments involving a large ensemble and is thus of significance for quantum metrolog yapplications.
基金NSFC-ISF(12161141018)National Natural Science Foundation of China(11974331,12027806,61675047,11874038)National Key Research and Development Program of China(2017YFA0304204,2016YFA0301700,2017YFA0304100,2016YFA0302000)。
文摘We experimentally demonstrate tunable non-Hermitian coupling in an atomic-vapor cell where atomic coherences in different optical channels are dissipatively coupled through atomic motion.Introducing a far-detuned light wall in the reservoir between the optical channels,we decorate the inter-channel coupling term so that it can be switched from dissipative to coherent.The tunable non-Hermiticity is then confirmed through measurements of the inter-channel light transport where the light-wall-induced phase shift is directly probed.Based on the tunable non-Hermiticity,we further discuss an exemplary scheme in which our setup can serve as a building block for the experimental study of exotic non-Hermitian criticality.
