Many-body coherence and entanglement probed by randomized correlation measurements

受控的纠缠与相干性切换

Chaos-controlled switching between entanglement and coherence

通过混沌控制实现纠缠与相干性的可切换切换，揭示了在不同混沌区域中纠缠和相干响应的翻转现象。

通过动力学去耦探测多重量子多体团簇

Multiple Quantum Many-Body Clustering Probed by Dynamical Decoupling

本研究利用动力学去耦技术探测密集自旋系统的多重量子演化，首次观察到相关自旋数量增加时团簇尺寸分布遵循二次定律，并实现了增强的灵敏度和缩短的实验时间。

Delayed choice experiment using atoms in optical cavity

In this article, we propose a method to realize the "delayed choice experiment" using ultra-cold atoms. Here we attempt to probe the "welcher-Weg" information without collapsing the wavefunction of the atom. This experiment consists of components built around proven techniques that are put together in novel configuration to preserve the coherence of the system during the measurement. The Ramsey interference is used to establish the wave nature of the atom and the particle nature of the atom is probed by detecting its internal state by performing a nondemolition measurement using an ultra-high …

In situ characterization of linear-optical networks in randomized boson sampling

We introduce a method for efficient, in situ characterization of linear-optical networks (LONs) in randomized boson-sampling (RBS) experiments. We formulate RBS as a distributed task between two parties, Alice and Bob, who share two-mode squeezed-vacuum states. In this protocol, Alice performs local measurements on her modes, either photon counting or heterodyne. Bob implements and applies to his modes the LON requested by Alice; at the output of the LON, Bob performs photon counting, the results of which he sends to Alice via classical channels. In the ideal situation, when Alice does photon …

Adaptive Quantum Optics with Spatially Entangled Photon Pairs

Light shaping facilitates the preparation and detection of optical states and underlies many applications in communications, computing, and imaging. In this Letter, we generalize light shaping to the quantum domain. We show that patterns of phase modulation for classical laser light can also shape higher orders of spatial coherence, allowing deterministic tailoring of high-dimensional quantum entanglement. By modulating spatially entangled photon pairs, we create periodic, topological, and random patterns of quantum illumination, without effect on intensity. We then structure the quantum illum…

测量辅助量子制冷机的最优相位控制

Optimal phase control of a measurement-assisted quantum refrigerator

本文提出通过随机相位控制测量辅助三能级量子制冷机，消除相干性反馈，最大化制冷功率，相位循环可提升约32%的制冷功率。

Scalable Method for Eliminating Residual $ZZ$ Interaction between Superconducting Qubits

Unwanted $ZZ$ interaction is a quantum-mechanical crosstalk phenomenon which correlates qubit dynamics and is ubiquitous in superconducting qubit systems. It adversely affects the quality of quantum operations and can be detrimental in scalable quantum information processing. Here we propose and experimentally demonstrate a practically extensible approach for complete cancellation of residual $ZZ$ interaction between fixed-frequency transmon qubits, which are known for long coherence and simple control. We apply to the intermediate coupler that connects the qubits a weak microwave drive at a p…

Backaction-free measurement of quantum correlations via quantum time-domain interferometry

Time-domain interferometry (TDI) is a method to probe space-time correlations among particles in condensed matter systems. Applying TDI to quantum systems raises the general question, whether two-time correlations can be reliably measured without adverse impact of the measurement backaction onto the dynamics of the system. Here, we show that a recently developed quantum version of TDI (QTDI) indeed can access the full quantum-mechanical two-time correlations without backaction. We further generalize QTDI to weak classical continuous-mode coherent input states, alleviating the need for single-p…

可编程量子多体系统中的量子同步与奇点态

Quantum synchronization and chimera states in a programmable quantum many-body system

该研究在可编程超导量子处理器中观察到对称保护的量子同步和量子奇点态，揭示了多体量子系统中非平衡动态相的实验可实现性。