Auto-compensating differential phase shift quantum key distribution

Compensating fictitious magnetic field gradients in optical microtraps by using elliptically polarized dipole light

Tightly focused optical dipole traps induce vector light shifts ("fictitious magnetic fields") which complicate their use for single-atom trapping and manipulation. The problem can be mitigated by adding a larger, real magnetic field, but this solution is not always applicable; in particular, it precludes fast switching to a field-free configuration. Here we show that this issue can be addressed elegantly by deliberately adding a small elliptical polarization component to the dipole beam. In our experiments with single $^{87}$Rb atoms in a chopped trap, we observe improvements up to a factor 1…

自动校准通用可编程光子电路：硬件纠错与缺陷韧性

Auto-calibrating Universal Programmable Photonic Circuits: Hardware Error-Correction and Defect Resilience

该研究验证了基于相移层与DFrFT交错的通用光子电路架构，在中间操作扰动、每层最多1个故障移相器的情况下仍保持通用性与缺陷韧性，可实现制造后自动校准以补偿相位元件误差缺陷。

基于量子自编码器的测试时训练：从分布偏移到含噪量子电路

Test-Time Training with Quantum Auto-Encoder: From Distribution Shift to Noisy Quantum Circuits

提出QTTT方法，利用量子自编码器自监督损失适应数据分布偏移和量子电路噪声，实验验证鲁棒性并给出理论保证，可作为量子机器学习即插即用扩展。

用于量子LDPC码中容错位移自同构的时变电路

Time-Dynamic Circuits for Fault-Tolerant Shift Automorphisms in Quantum LDPC Codes

本研究提出时变电路实现量子LDPC码中容错位移自同构，显著降低逻辑错误率，提升错误容忍性和效率。

Automatical generation of nonadiabatic conditional geometric phase shift via a noncoplanar fiber system

A new scheme of realizing the nonadiabatic conditional geometric phase shift via a noncoplanar (and coiled) fiber system is presented in this Letter. It is shown that the effective Hamiltonian that describes the interaction of polarized photons with the fiber medium is just the Wang-Keiji type of Hamiltonian. This, therefore, means that the coiled fiber system may be an ideal implementation of realizing the nonadiabatic geometric phase gates for the topological quantum computation. The remarkable feature of the present method is that it can automatically meet the conditions and requirements pr…

High-speed free-space quantum key distribution with automatic tracking for short-distance urban links

High-speed free-space quantum key distribution located in urban environment offers an interesting alternative to public key encryption - whose security strength is yet to be mathematically proven. To achieve this, three main objectives need to be accomplished: both the emitter and receiver have to be capable of transmitting and receiving at high speed - with the selection of the source's wavelength and detectors being of especial importance - the error rate needs to be kept at a minimum, especially that due to solar background radiation; and finally, a fast automatic tracking system, capable o…