Protected cat states from kinetic driving of a boson gas

拓扑保护的贝尔-猫态在简单自旋模型中

Topologically protected Bell-cat states in a simple spin model

该研究在简单自旋模型中发现拓扑保护的贝尔-猫态，通过驱动中心自旋实现其渐进创建和移动，并探讨其对噪声的鲁棒性。

Stroboscopic Symmetry-Protected Topological Phases

Symmetry-protected topological (SPT) phases of matter have been the focus of many recent theoretical investigations, but controlled mechanisms for engineering them have so far been elusive. In this work, we demonstrate that by driving interacting spin systems periodically in time and tuning the available parameters, one can realize lattice models for bosonic SPT phases in the limit where the driving frequency is large. We provide concrete examples of this construction in one and two dimensions, and discuss signatures of these phases in stroboscopic measurements of local observables.

Floquet symmetry-protected topological phases in cold atomic systems

We propose and analyze two distinct routes toward realizing interacting symmetry-protected topological (SPT) phases via periodic driving. First, we demonstrate that a driven transverse-field Ising model can be used to engineer complex interactions which enable the emulation of an equilibrium SPT phase. This phase remains stable only within a parametric time scale controlled by the driving frequency, beyond which its topological features break down. To overcome this issue, we consider an alternate route based upon realizing an intrinsically Floquet SPT phase that does not have any equilibrium a…

Shortcuts to adiabatic cat-state generation in bosonic Josephson junctions

We propose a quantum speedup method for adiabatic generation of cat states in bosonic Josephson junctions via shortcuts to adiabaticity. We apply approximated counter-diabatic driving to a bosonic Josephson junction using the Holstein-Primakoff transformation. In order to avoid the problem of divergence in counter-diabatic driving, we take finite-size corrections into account. The resulting counter-diabatic driving is well-defined over whole processes. Schedules of the counter-diabatic driving consist of three steps; the counter-diabatic driving in the disordered phase, smoothly and slowly app…

Homodyne versus photon-counting quantum trajectories for dissipative Kerr resonators with two-photon driving

We investigate two different kinds of quantum trajectories for a nonlinear photon resonator subject to two-photon pumping, a configuration recently studied for the generation of photonic Schroedinger cat states. In the absence of feedback control and in the strong-driving limit, the steady-state density matrix is a statistical mixture of two states with equal weight. While along a single photon-counting trajectory the systems intermittently switches between an odd and an even cat state, we show that upon homodyne detection the situation is different. Indeed, homodyne quantum trajectories revea…

驱动超流体中的猫态：信号形状和切换协议的作用

Cat states in a driven superfluid: role of signal shape and switching protocol

研究通过驱动超流体中的猫态，探讨信号形状和切换协议对超流体行为的影响。