Electrically Tunable Macroscopic Quantum Tunneling in a Graphene-based Josephson Junction

TL;DR

This paper demonstrates the control of macroscopic quantum tunneling in a graphene-based Josephson junction through gate voltage, revealing potential for tunable quantum bits by observing phase particle behavior and energy level quantization.

Contribution

It introduces a graphene-based Josephson junction with electrically tunable macroscopic quantum tunneling, enabling gate-controlled quantum state manipulation.

Findings

Observation of crossover from classical to quantum regime in switching-current distribution

Microwave spectroscopy reveals multi-photon absorption and discrete energy levels

Gate voltage controls the MQT crossover temperature and energy level spacing

Abstract

Stochastic switching-current distribution in a graphene-based Josephson junction exhibits a crossover from the classical to quantum regime, revealing the macroscopic quantum tunneling (MQT) of a Josephson phase particle at low temperatures. Microwave spectroscopy measurements indicate a multi-photon absorption process occurring via discrete energy levels in washboard potential well. The crossover temperature for MQT and the quantized level spacing are controlled with the gate voltage, implying its potential application to gate-tunable superconducting quantum bits.