Energy-level quantization and single-photon control of phase slips in YBa₂Cu₃O_7-x nanowires

Area of Science:

• Quantum Computing and Technology
• Condensed Matter Physics
• Materials Science

Background:

• Superconducting quantum circuits are advancing, but require devices with longer decoherence times at higher temperatures.
• Superconducting nanowires with quantum phase slips present a promising avenue for novel quantum devices.
• Existing quantum devices often face limitations in operating temperature and decoherence times.

Purpose of the Study:

• To demonstrate YBa2Cu3O7-x nanowires exhibiting phase-slip dynamics.
• To investigate the switching-current statistics of these nanowires at temperatures below 20 K.
• To provide evidence for energy-level quantization in superconducting nanowires.

Main Methods:

• Fabrication and characterization of YBa2Cu3O7-x nanowires.
• Measurement of switching-current statistics at cryogenic temperatures (below 20 K).
• Application of theoretical models developed for Josephson junctions to analyze nanowire behavior.

Main Results:

• Demonstrated phase-slip dynamics in YBa2Cu3O7-x nanowires.
• Observed energy-level quantization, supported by theoretical model analysis.
• Achieved a crossover temperature to the quantum regime of 12-13 K and an excited-state lifetime exceeding 20 ms at 5.4 K, outperforming conventional Josephson junctions.
• Showed that single-photon absorption alters the phase-slip and quantum state of the nanowire.

Conclusions:

• YBa2Cu3O7-x nanowires with quantum phase slips are viable candidates for advanced quantum technologies.
• The observed quantum phenomena, including energy-level quantization and long lifetimes, surpass conventional Josephson junctions.
• The sensitivity to single-photon absorption highlights potential for high-temperature, high-resolution single-photon detectors.