Errors in quantum optimal control and strategy for the search of easily implementable control pulses

利用有限宽度脉冲实现鲁棒的高阶量子模拟

Robust high-order quantum simulation using finite-width pulses

本文提出一种框架，将一阶脉冲序列提升为高阶序列，保持有限脉宽效应下的鲁棒性，并通过动态校正门编译为可实现的有限宽度脉冲，实现任意高阶误差缩放。

Witnessing quantum capacities of correlated channels

We test a general method to detect lower bounds of the quantum channel capacity for two-qubit correlated channels. We consider in particular correlated dephasing, depolarising and amplitude damping channels. We show that the method is easily implementable, it does not require a priori knowledge about the channels, and it is very efficient, since it does not rely on full quantum process tomography.

用于量子态操控的激光场自动优化

Automated Optimization of Laser Fields for Quantum State Manipulation

提出结合自动微分的梯度优化方法设计量子控制脉冲，解决高维参数空间下解析法或手动调优低效的问题，实现高保真布居数转移且脉冲平滑可实验实现。

Laser phase modulation approaches towards ensemble quantum computing

Selective control of decoherence is demonstrated for a multilevel system by generalizing the instantaneous phase of any chirped pulse as individual terms of a Taylor series expansion. In the case of a simple two-level system, all odd terms in the series lead to population inversion while the even terms lead to self-induced transparency. These results also hold for multiphoton transitions that do not have any lower-order photon resonance or any intermediate virtual state dynamics within the laser pulse-width. Such results form the basis of a robustly implementable CNOT gate.

Time-resolved homodyne characterization of individual quadrature-entangled pulses

We describe a simple and efficient setup to generate and characterize femtosecond quadrature-entangled pulses. Quantum correlations equivalent to about 2.5 dB squeezing are efficiently and easily reached using the non-degenerate parametric amplification of femtosecond pulses through a single-pass in a thin (0.1 mm) potassium niobate crystal. The entangled pulses are then individually sampled to characterize the non-separability and the entropy of formation of the states. The complete experiment is analysed in the time-domain, from the pulsed source of quadrature entanglement to the time-resolv…

少光子脉冲波导量子电动力学中单人工原子的量子动力学：频率依赖散射理论与时间依赖矩阵积态

Quantum dynamics of few-photon pulsed waveguide-QED with a single artificial atom: frequency-dependent scattering theory and time-dependent matrix product states

研究少光子脉冲在波导量子电动力学中与单人工原子的散射动力学，比较输入输出散射方法与矩阵积态方法，分析频率依赖散射矩阵和时间依赖波函数的计算，展示双光子相关函数的特征形状及非线性动力学行为。