发表机构
Centre for Quantum Technologies, National University of Singapore; Indian Institute of Science Education and Research Tirupati; Department of Physics, Simon Fraser University; Department of Physics, University of Oxford; Department of Physics, National University of Singapore（新加坡国立大学量子技术中心; 蒂鲁帕蒂印度科学教育与研究所; 西蒙菲莎大学物理系; 牛津大学物理系; 新加坡国立大学物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出在耦合transmon量子比特的超导谐振子中实现可编程非高斯相位门的系统框架，成功实现立方相位门、双阱势、近似莫尔斯门等，为连续变量量子信息处理和非简谐量子仿真提供可重构实用途径。
AI 中文摘要
连续变量量子系统为通用量子信息处理和真实世界过程（如分子物理与化学反应）的模拟量子仿真提供了资源高效的途径。然而，实现这些应用需要可按需设计的、执行非简谐势的非高斯操作，这一任务极具挑战性。在此，我们展示了一个系统框架，用于在与transmon量子比特耦合的超导谐振子中实现可编程非高斯相位门$e^{-iV(\hat{X})}$，该相位门对应于势$V(\hat{X})$的脉冲作用。我们利用源自玻色量子信号处理的模块化电路，通过改变一系列量子比特旋转操作并插入固定校准的控制幺正操作，在单块硬件上实现了多种目标非简谐势。我们首先演示了立方相位门，这是通用量子信息处理的关键组成部分；所得到的高保真非高斯态与通过我们的逐点力重构方法重构的势共同验证了目标门的立方特性。随后，我们设计了一类双阱势（隧穿和偏置转移过程的相关模型），并通过实验验证了其双阱拓扑结构和可调不对称性。最后，我们设计了近似莫尔斯门（向分子振动系统的真实势迈出的一步），并为指数形式的高质量工程与重构提供了具体路径。综上，这些结果为连续变量量子信息处理和非简谐量子仿真建立了实用且可重构的途径。
英文摘要
Continuous-variable quantum systems offer a resource-efficient route to universal quantum information processing and analogue quantum simulation of real-world processes, such as molecular physics and chemical reactions. Realising these applications, however, requires non-Gaussian operations that implement anharmonic potentials, which are challenging to engineer on demand. Here, we demonstrate a systematic framework to implement programmable non-Gaussian phase gates $e^{-iV(\hat{X})}$, corresponding to the impulsive action of a potential $V(\hat{X})$, in a superconducting harmonic oscillator coupled to a transmon qubit. Using modular circuits derived from bosonic quantum signal processing, we realise a range of target anharmonic potentials on a single piece of hardware by varying a set of qubit rotations interleaved with a fixed calibrated control unitary. We first demonstrate a cubic phase gate, a key ingredient for universal quantum information processing. The resulting high-fidelity non-Gaussian states and the potential reconstructed using our pointwise force reconstruction method jointly confirm the cubic nature of the target gate. We then engineer a family of double-well potentials, relevant models of tunnelling and biased transfer processes, and experimentally validate the double-well topology and the tunable asymmetry. Finally, we engineer an approximate Morse gate, a step towards realistic potentials of molecular vibrational systems, and provide a concrete path towards high-quality engineering and reconstruction of the exponential form. Together, these results establish a practical and reconfigurable route towards continuous-variable quantum information processing and anharmonic quantum simulation.
CommentsMain text: 6 pages with 4 figures. Supplemental Material: 20 pages with 4 figures and 15 tables
