Polynomial procedure of avoiding multiqubit errors arising due to qubit-qubit interaction

Spin Squeezing and Quantum Correlations

Recent years have witnessed revolutionary improvement in the production, manipulation, characterization and quantification of multiatom (multiqubit) states - because of their promising applications in high precision atomic clocks, atomic interferrometry, quantum metrology and quantum information protocols. In the characterization and quantification of non-classical atomic correlations, two concepts namely, spin squeezing and quantum entanglement emerge. While spin squeezing originates from the uncertainty relation between atomic collective angular momentum operators, entanglement is a peculiar…

Avoiding irreversibility: engineering resonant conversions of quantum resources

We identify and explore the intriguing property of resource resonance arising within resource theories of entanglement, coherence and thermodynamics. While the theories considered are reversible asymptotically, the same is generally not true in realistic scenarios where the available resources are bounded. The finite-size effects responsible for this irreversibility could potentially prohibit small quantum information processors or thermal machines from achieving their full potential. Nevertheless, we show here that by carefully engineering the resource interconversion process any such losses …

Robustness of error-suppressing entangling gates in cavity-coupled transmon qubits

Superconducting transmon qubits comprise one of the most promising platforms for quantum information processing due to their long coherence times and to their scalability into larger qubit networks. However, their weakly anharmonic spectrum leads to spectral crowding in multiqubit systems, making it challenging to implement fast, high-fidelity gates while avoiding leakage errors. To address this challenge, we use a protocol known as SWIPHT [Phys. Rev. B 91, 161405(R) (2015)], which yields smooth, simple microwave pulses designed to suppress leakage without sacrificing gate speed through spectr…

避免重六边形架构中的缺陷

Avoiding Defects within Heavy-Hexagon Architecture

针对连通性2-3的重六边形架构，提出仅需2个测量周期的缺陷规避方案，在IBM量子硬件上验证可使逻辑X、Z错误率各降约10%，解决了高连通性架构缺陷处理方法不适用于重六边形架构的问题。

基于交叉共振的量子比特架构中量子串扰的缓解

Mitigation of quantum crosstalk in cross-resonance based qubit architectures

本研究提出一种基于交叉共振门的transmon架构，被动缓解ZZ串扰和频率碰撞，扩展快速高保真CR门操作区域，并给出误差识别模型，有助于提升大规模固定频率量子处理器性能。

态平均轨道优化VQE：一种用于基态与激发电子态民主描述的量子算法

State-Averaged Orbital-Optimized VQE: A quantum algorithm for the democratic description of ground and excited electronic states

本文提出SA-OO-VQE混合量子-经典算法，通过态平均轨道优化VQE方法平等处理简并态，在含噪声中等规模量子计算机上同时求解基态与激发态，避免特定态方法在避免交叉和锥形交叉处的数值优化困难。