Fast preparation of many-body entangled atomic states in spin-mixing Hamiltonians

The production of large many-body entangled atomic states is an important target for quantum-enhanced metrology. One established method is to use spin-mixing interactions for spinor atoms, which arise naturally in spinor Bose-Einstein condensates [1], or can be engineered in cavity QED [2]. The spin-mixing Hamiltonian has highly entangled ground states in several limits, including the twin Fock state and macroscopic spin singlet [3]. However, they cannot be accessed by adiabatic passage for large atom number as the energy gap closes as the atom number diverges [4,5]. Here, we explore methods to bypass this problem, and propose fast protocols to prepare high-fidelity many-body entangled ground states.

[1] DM Stamper-Kurn & M Ueda, Rev. Mod. Phys. 85, 1191 (2013)

[2] EJ Davis et al, Phys. Rev. Lett. 122, 010405 (2019)

[3] Z Zhang & L-M Duan, Phys. Rev. Lett. 111, 180401 (2013)

[4] TM Hoang et al, Proc. Natl. Acad. Sci. USA 113, 9475 (2016)

[5] X-Y Luo et al, Science 355, 6325 (2017)