Du Botao, Suresh Ramya, López Santiago, Cadiente Jeremy, Ma Ruichao
Department of Physics and Astronomy, <a href="https://ror.org/02dqehb95">Purdue University</a>, West Lafayette, Indiana 47907, USA.
Phys Rev Lett. 2024 Aug 9;133(6):060601. doi: 10.1103/PhysRevLett.133.060601.
Transport measurements are fundamental for understanding condensed matter phenomena, from superconductivity to the fractional quantum Hall effect. Analogously, they can be powerful tools for probing synthetic quantum matter in quantum simulators. Here we demonstrate the measurement of in situ particle current in a superconducting circuit lattice and apply it to study transport in both coherent and bath-coupled lattices. Our method utilizes controlled tunneling in a double-well potential to map current to on-site density, revealing site-resolved current and current statistics. We prepare a strongly interacting Bose-Hubbard lattice at different lattice fillings, and observe the change in current statistics as the many-body states transition from superfluid to Mott insulator. Furthermore, we explore nonequilibrium current dynamics by coupling the lattice to engineered driven-dissipative baths that serve as tunable particle source and drain. We observe steady-state current in discrete conduction channels and interaction-assisted transport. These results establish a versatile platform to investigate microscopic quantum transport in superconducting circuits.
输运测量对于理解凝聚态物质现象至关重要，从超导到分数量子霍尔效应皆是如此。类似地，它们可以成为在量子模拟器中探测合成量子物质的有力工具。在此，我们展示了在超导电路晶格中对原位粒子电流的测量，并将其应用于研究相干晶格和与热库耦合的晶格中的输运。我们的方法利用双阱势中的可控隧穿将电流映射到局域密度，揭示了位点分辨的电流和电流统计。我们在不同的晶格填充下制备了强相互作用的玻色 - 哈伯德晶格，并观察到随着多体状态从超流体转变为莫特绝缘体时电流统计的变化。此外，我们通过将晶格与作为可调粒子源和漏的工程化驱动 - 耗散热库耦合来探索非平衡电流动力学。我们在离散传导通道中观察到稳态电流以及相互作用辅助输运。这些结果建立了一个通用平台，用于研究超导电路中的微观量子输运。
