Macroscopic quantum tunneling effect ofZ2topological order

Macroscopic Quantum Tunneling in Magnetic Nanostructures

Theoretical foundations of the problem of quantum spin tunneling in magnetic nanostructures are presented. Several model problems are considered in detail, including recent new results on tunneling in antiferromagnetic nanoparticles and topologically nontrivial magnetic structures in systems with reduced dimension.

Macroscopic quantum tunneling and quasiparticle-tunneling blockade effect in s-wave/d-wave hybrid junctions

S. Kawabata,1,2 A. A. Golubov,1 Ariando,1 C. J. M. Verwijs,1 H. Hilgenkamp,1 and J. R. Kirtley3 1Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands 2Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan 3IBM T. J. Watson Research Center, Yorktown Hei...

Quantum terahertz electrodynamics and macroscopic quantum tunneling in layered superconductors.

We derive a quantum field theory of Josephson plasma waves (JPWs) in layered superconductors, which describes two types of interacting JPW bosonic quanta (one heavy and one lighter). We propose a mechanism of enhancement of macroscopic quantum tunneling (MQT) in stacks of intrinsic Josephson junctions. Because of the long-range interaction between junctions in layered superconductors, the calcu...

Effects of dissipation and temperature on macroscopic quantum tunneling.

Enhancement of macroscopic quantum tunneling by Landau-Zener transitions.

Motivated by recent realizations of qubits with a readout by macroscopic quantum tunneling in a Josephson junction, we study the problem of barrier penetration in the presence of coupling to a spin-1 / 2 system. It is shown that, when the diabatic potentials for fixed spin intersect in the barrier region, Landau-Zener transitions lead to an enhancement of the tunneling rate. The effect of these...