Dissipative preparation of phase- and number-squeezed states with ultracold atoms

Abstract

We develop a dissipative quantum state preparation scheme for the creation of phase-and number-squeezed states. It utilizes ultracold atoms in a double-well configuration immersed in a background Bose-Einstein condensate, with the latter consisting of an atom species different from the atoms in the double well and acting as a dissipative quantum reservoir. We derive a master equation for this system starting from microscopic physics and show that squeezing develops on a time scale proportional to 1/N , where N is the number of particles in the double well. This scaling, caused by bosonic enhancement, allows us to make the time scale for the creation of squeezed states very short. The lifetime of squeezed states is limited by dephasing arising from the intrinsic structure of the setup. However, the dephasing can be avoided by stroboscopically switching the driving off and on. We show that this approach leads to robust stationary squeezed states. Finally, we provide the necessary ingredients for a potential experimental implementation by specifying a parameter regime for rubidium atoms that leads to squeezed states.

Quantum trajectories and open many-body quantum systems

“…Such effects can also be used to manipulate or protect states in quantum computations [122,123] and quantum memories [124], as well as to prepare entangled states dissipatively [125][126][127], or realise specific quantum gates for group-II atoms [128,129]. It is also possible to generate spin-squeezed states using collisional loss in fermions [130] or collisions with background gases [131], as well as to protect states during adiabatic state preparation [132].…”

“…Such effects can also be used to manipulate or protect states in quantum computations [122,123] and quantum memories [124], as well as to prepare entangled states dissipatively [125][126][127], or realise specific quantum gates for group-II atoms [128,129]. It is also possible to generate spin-squeezed states using collisional loss in fermions [130] or collisions with background gases [131], as well as to protect states during adiabatic state preparation [132].Studies of dissipation have more recently included investigating the competition between dissipation and coherent dynamics, including dissipative phase transitions [133][134][135], excitation dynamics in clouds of Rydberg atoms [95,[136][137][138][139][140][141], and collective spin dynamics on the clock transition in group II atoms [142]. Other work has begun to characterise dissipative driving processes by identifying universal classes of states and phase transitions that can be realised in this way [143,144].…”

Report on scipost_202009_00014v1

“…More recently, another point of view has been taken. Environments are particularly tailored in order to stabilize and control quantum many-body states [4][5][6][7][8]. However, it has been shown that the dynamic properties of such states can have very distinct behavior from their Hamiltonian counterparts [9].…”

Dissipative Bose–Einstein condensation in contact with a thermal reservoir

“…In light of these limitations, it is quite remarkable that a class of open quantum many-body models [12] can be solved without approximations. This is of particular interest since open quantum systems with engineered couplings to an environment [13] have been proposed recently for the preparation of quantum states [14][15][16][17][18], quantum simulation [19][20][21], as well as quantum computing [14,[22][23][24]. Typically, the nonequilibrium steady state (NESS) of the engineered dissipative process, which defines a unique fixed point for the dynamics, is known by construction 2 ; examples include condensates of bosons or η states of fermions [25,26], condensates of quantum spins or hardcore bosons [27], d-wave pairing states of fermions [28,29], and various topologically ordered states [30][31][32][33].…”