Showing papers by "Yu. A. Pashkin published in 2021"

Nanoscale real-time detection of quantum vortices at millikelvin temperatures.

Abstract: Since we still lack a theory of classical turbulence, attention has focused on the conceptually simpler turbulence in quantum fluids. Reaching a better understanding of the quantum case may provide additional insight into the classical counterpart. That said, we have hitherto lacked detectors capable of the real-time, non-invasive probing of the wide range of length scales involved in quantum turbulence. Here we demonstrate the real-time detection of quantum vortices by a nanoscale resonant beam in superfluid 4He at 10 mK. Essentially, we trap a single vortex along the length of a nanobeam and observe the transitions as a vortex is either trapped or released, detected through the shift in the beam resonant frequency. By exciting a tuning fork, we control the ambient vortex density and follow its influence on the vortex capture and release rates demonstrating that these devices are capable of probing turbulence on the micron scale. Previous work has shown the detection of quantum turbulence with mechanical resonators but with limited spatial and temporal resolution. Here, the authors demonstrate real-time detection of single quantum vortices in superfluid 4He with millisecond and micron resolution at temperatures of 10 millikelvin.

Nongalvanic Calibration and Operation of a Quantum Dot Thermometer

Abstract: A quantum dot can measure ultracold temperatures without the need for direct electrical connections to the outside world.