Macroscopic quantum tunneling and dissipation in c-axis twist Josephson junctions

Abstract

We study macroscopic quantum tunneling (MQT) in c-axis twist superconductor Josephson junctions. By using the functional integral method and the instanton theory we have obtained the analytical expression of the MQT rate (the inverse lifetime of the metastable state). In the case of the zero twist angle, we find that the system shows the super-Ohmic dissipation due to the presence of the nodal quasiparticle tunneling. Therefore, the MQT rate is strongly suppressed in compared with the finite twist angle cases.