2023/02/15 by Chaudhary, Manish, Ilo-Okeke, Ebubechukwu O., Ivannikov, Valentin +1
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2302.07526
We develop a scheme to prepare a macroscopic maximally entangled state (MMES) between two atomic ensembles using adaptive quantum nondemolition (QND) measurements. The quantum state of the system is evolved using a sequence of QND measurements followed by adaptive unitaries, such that the desired measurement outcome is obtained with asymptotically unit probability. This procedure is repeated in z and x spin basis alternately such that the state converges deterministically towards the maximally entangled state. Up to a local spin-basis rotation, the maximally entangled state has zero total spin angular momentum, i.e. it is a singlet state. Our protocol does not perform postselection and works beyond the Holstein-Primakoff regime for the atomic spin degrees of freedom, producing genuine macroscopic entanglement.