标题： 量子传感器用于微观隧穿系统 显示英文标题

标题： Quantum Sensors for Microscopic Tunneling Systems

摘要： 玻璃的异常低温特性源于内在的可激发实体，即所谓的隧穿双态系统（TLS），其微观性质几十年来一直让固态物理学家感到困惑。 TLS在微制造的量子器件中变得尤为重要，例如超导量子比特，其中它们是退相干的主要来源。 在此，我们提出一种方法，在几乎任意材料沉积的薄膜中表征单个TLS。 该材料用作电容器的介电材料，该电容器并联在超导量子比特的约瑟夫森结上。 在这种混合量子系统中，量子比特作为接口来检测和控制单个TLS。 我们展示了TLS共振的光谱测量，评估了它们对施加应变和直流电场的耦合，并发现了样品材料中相干TLS之间存在强烈相互作用的证据。 我们的方法为量子材料光谱学开辟了道路，以研究隧穿缺陷的结构，并开发超导量子计算机发展所迫切需要的低损耗介电材料。 显示英文摘要

摘要： The anomalous low-temperature properties of glasses arise from intrinsic excitable entities, so-called tunneling Two-Level-Systems (TLS), whose microscopic nature has been baffling solid-state physicists for decades. TLS have become particularly important for micro-fabricated quantum devices such as superconducting qubits, where they are a major source of decoherence. Here, we present a method to characterize individual TLS in virtually arbitrary materials deposited as thin-films. The material is used as the dielectric in a capacitor that shunts the Josephson junction of a superconducting qubit. In such a hybrid quantum system the qubit serves as an interface to detect and control individual TLS. We demonstrate spectroscopic measurements of TLS resonances, evaluate their coupling to applied strain and DC-electric fields, and find evidence of strong interaction between coherent TLS in the sample material. Our approach opens avenues for quantum material spectroscopy to investigate the structure of tunneling defects and to develop low-loss dielectrics that are urgently required for the advancement of superconducting quantum computers.