Halbertal D, Cuppens J, Shalom M Ben, Embon L, Shadmi N, Anahory Y, Naren H R, Sarkar J, Uri A, Ronen Y, Myasoedov Y, Levitov L S, Joselevich E, Geim A K, Zeldov E
Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and the Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
Nature. 2016 Nov 17;539(7629):407-410. doi: 10.1038/nature19843.
Energy dissipation is a fundamental process governing the dynamics of physical, chemical and biological systems. It is also one of the main characteristics that distinguish quantum from classical phenomena. In particular, in condensed matter physics, scattering mechanisms, loss of quantum information or breakdown of topological protection are deeply rooted in the intricate details of how and where the dissipation occurs. Yet the microscopic behaviour of a system is usually not formulated in terms of dissipation because energy dissipation is not a readily measurable quantity on the micrometre scale. Although nanoscale thermometry has gained much recent interest, existing thermal imaging methods are not sensitive enough for the study of quantum systems and are also unsuitable for the low-temperature operation that is required. Here we report a nano-thermometer based on a superconducting quantum interference device with a diameter of less than 50 nanometres that resides at the apex of a sharp pipette: it provides scanning cryogenic thermal sensing that is four orders of magnitude more sensitive than previous devices-below 1 μK Hz. This non-contact, non-invasive thermometry allows thermal imaging of very low intensity, nanoscale energy dissipation down to the fundamental Landauer limit of 40 femtowatts for continuous readout of a single qubit at one gigahertz at 4.2 kelvin. These advances enable the observation of changes in dissipation due to single-electron charging of individual quantum dots in carbon nanotubes. They also reveal a dissipation mechanism attributable to resonant localized states in graphene encapsulated within hexagonal boron nitride, opening the door to direct thermal imaging of nanoscale dissipation processes in quantum matter.
能量耗散是支配物理、化学和生物系统动力学的一个基本过程。它也是区分量子现象和经典现象的主要特征之一。特别是在凝聚态物理中，散射机制、量子信息的丢失或拓扑保护的破坏都深深植根于耗散发生的方式和位置的复杂细节之中。然而，系统的微观行为通常不是根据耗散来表述的，因为能量耗散在微米尺度上不是一个易于测量的量。尽管纳米尺度的温度测量最近引起了广泛关注，但现有的热成像方法对量子系统的研究不够敏感，也不适用于所需的低温操作。在这里，我们报告了一种基于超导量子干涉器件的纳米温度计，其直径小于50纳米，位于尖锐移液管的顶端：它提供扫描低温热传感，比以前的器件灵敏四个数量级——低于1 μK Hz。这种非接触、非侵入式的温度测量允许对极低强度的纳米尺度能量耗散进行热成像，低至40飞瓦的基本兰道尔极限，用于在4.2开尔文温度下以1吉赫兹的频率连续读出单个量子比特。这些进展使得能够观察到由于碳纳米管中单个量子点的单电子充电而导致的耗散变化。它们还揭示了一种归因于封装在六方氮化硼中的石墨烯中共振局域态的耗散机制，为量子物质中纳米尺度耗散过程的直接热成像打开了大门。
