Energy-level quantization in YBa2Cu3O7-x phase-slip nanowires

TL;DR

This paper demonstrates energy-level quantization in YBa2Cu3O7-x nanowires with phase-slip dynamics, showing potential for high-temperature quantum devices with long coherence times and applications in quantum sensing and computing.

Contribution

It provides experimental evidence of energy-level quantization in high-temperature superconducting nanowires, extending quantum device operation to higher temperatures.

Findings

Energy-level quantization observed below 20 K

Crossover to quantum regime at 12-13 K

Excited state lifetime exceeds 20 ms at 5.4 K

Abstract

Significant progress has been made in the development of superconducting quantum circuits, however new quantum devices that have longer decoherence times at higher temperatures are urgently required for quantum technologies. Superconducting nanowires with quantum phase slips are promising candidates for use in novel devices that operate on quantum principles. Here, we demonstrate ultra-thin YBa2Cu3O7-x nanowires with phase-slip dynamics and study their switching-current statistics at temperatures below 20 K. We apply theoretical models that were developed for Josephson junctions and show that our results provide strong evidence for energy-level quantization in the nanowires. The crossover temperature to the quantum regime is 12-13 K, while the lifetime in the excited state exceeds 20 ms at 5.4 K. Both values are at least one order of magnitude higher than those in conventional Josephson junctions based on low-temperature superconductors. We also show how the absorption of a single photon changes the phase-slip and quantum state of a nanowire, which is important for the development of single-photon detectors with high operating temperature and superior temporal resolution. Our findings pave the way for a new class of superconducting nanowire devices for quantum sensing and computing.