Macroscopic quantum tunneling and quasiparticle dissipation in d-wave superconductor Josephson junctions -: art. no. 132505

We examine the macroscopic quantum tunneling (MQT) in high-T-c superconductor Josephson junctions with a d-wave order parameter. Using a microscopic Hamiltonian and the functional integral method, we analytically obtain the MQT rate (the inverse lifetime of the metastable state) for the c-axis twist Josephson junctions. In the case of the zero twist angle, the system shows the super-Ohmic dissipation due to the presence of the nodal quasiparticle tunneling. Therefore, the MQT rate is strongly suppressed in comparison with the finite twist angle cases.