Electrically Tunable Macroscopic Quantum Tunneling in a Graphene-based   Josephson Junction
  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. 
Gil-Ho Lee (1), Dongchan Jeong (1), Jae-Hyun Choi (1), Yong-Joo Doh   (2) and Hu-Jong Lee (1) ((1) Department of Physics, Po...
cond-mat.mes-hall cond-mat.supr-con