Nanoscale thermal imaging of dissipation in quantum systems

by Eli Zeldov

at Condensed Matter Seminar

Mon, 30 Oct 2017, 11:30
Physics building (#54) room 207

Abstract

Energy dissipation is a fundamental process governing the dynamics of physical systems In condensed matter physics in particular 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 Despite its vital importance direct imaging and microscopy of dissipation in quantum systems is currently impossible because the existing thermal imaging methods lack the necessary sensitivity and are unsuitable for low temperature operation We developed a scanning nanoSQUID with sub 50 nm diameter that resides at the apex of a sharp pipette 1 that can act simultaneously as nanomagnetometer with single spin sensitivity and as nanothermometer providing cryogenic thermal imaging with four orders of magnitude improved thermal sensitivity of below 1 K Hz1 2 2 The non contact non invasive thermometry allows thermal imaging of minute energy dissipation down to the fundamental Landauer limit of 40 fW for continuous readout of a single qubit at 1 GHz at 4 2 K In addition by varying the potential between the SQUID on tip and the sample a nanoscale spectroscopic analysis of the dissipation process can be attained These advances enable observation of changes in dissipation due to single electron charging of individual quantum dots in carbon nanotubes Our thermal imaging study of hBN encapsulated graphene reveals a fascinating dissipation mechanism due to resonant localized states providing the first visualization of inelastic electron scattering from individual atomic defects 3 opening the door to direct imaging and spectroscopy of dissipation processes in quantum matter 1 Vasyukov et al Nature Nanotech 8 639 2013 2 D Halbertal J Cuppens M Ben Shalom L Embon N Shadmi Y Anahory H R Naren J Sarkar A Uri Y Ronen Y Myasoedov L S Levitov E Joselevich A K Geim and E Zeldov Nature 539 407 2016 3 D Halbertal M Ben Shalom A Uri K Bagani A Y Meltzer I Marcus Y Myasoedov J Birkbeck L S Levitov A K Geim and E Zeldov arXiv:1710 01486 2017

Created on 23-10-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 23-10-2017 by Bar Lev, Yevgeny (ybarlev)