Discrete time-crystalline order enabled by quantum many-body scars: entanglement steering via periodic driving

Optimal steering of matrix product states and quantum many-body scars

Ongoing development of quantum simulators allows for a progressively finer degree of control of quantum many-body systems. This motivates the development of efficient approaches to facilitate the control of such systems and enable the preparation of non-trivial quantum states. Here we formulate an approach to control quantum systems based on matrix product states~(MPS). We compare counter-diabatic and leakage minimization approaches to the so-called local steering problem, that consists in finding the best value of the control parameters for generating a unitary evolution of the specific MPS s…

Quantum Many-Body Scars and Space-Time Crystalline Order from Magnon Condensation

We study the eigenstate properties of a nonintegrable spin chain that was recently realized experimentally in a Rydberg-atom quantum simulator. In the experiment, long-lived coherent many-body oscillations were observed only when the system was initialized in a particular product state. This pronounced coherence has been attributed to the presence of special "scarred" eigenstates with nearly equally-spaced energies and putative nonergodic properties despite their finite energy density. In this paper we uncover a surprising connection between these scarred eigenstates and low-lying quasiparticl…

Homodyne detection of non-Gaussian quantum steering

Quantum correlations are at the core of current developments in quantum technologies. Certification protocols of entanglement and steering, suitable for continuous-variable non-Gaussian states are scarce and generally highly demanding from an experimental point of view. We propose a protocol based on Fisher information for witnessing steering in general continuous-variable bipartite states, through homodyne detection. It proves to be relevant for the detection of non-Gaussian steering in scenarios where witnesses based on Gaussian features like the covariance matrix are shown to fail.

Controlling many-body dynamics with driven quantum scars in Rydberg atom arrays

Controlling non-equilibrium quantum dynamics in many-body systems is an outstanding challenge as interactions typically lead to thermalization and a chaotic spreading throughout Hilbert space. We experimentally investigate non-equilibrium dynamics following rapid quenches in a many-body system composed of 3 to 200 strongly interacting qubits in one and two spatial dimensions. Using a programmable quantum simulator based on Rydberg atom arrays, we probe coherent revivals corresponding to quantum many-body scars. Remarkably, we discover that scar revivals can be stabilized by periodic driving, w…

通过 Floquet 疤痕态工程化实现超越预热化 regime 的次谐波响应

Engineering subharmonic responses beyond prethermalization via Floquet scar states

本文提出在广义 PXP 模型中利用周期驱动产生的 Floquet 疤痕态实现次谐波响应，并借助 $SO(3)$-FSA 阐明其可超越传统预热化限制。

三体耦合谐振子中的爱因斯坦-波多尔斯基-罗森引导

Einstein-Podolsky-Rosen Steering in Three Coupled Harmonic Oscillators

研究三体耦合谐振子中量子引导的生成与增强机制，揭示激发态和混合角对引导的影响。