Coupling mechanism between microscopic two-level system and superconducting qubits

  1. Zhen-Tao Zhang,
  2. and Yang Yu
We propose a scheme to clarify the coupling nature between superconducting Josephson qubits andmicroscopic two-level systems. Although dominant interest in studying two-level systems
was in phase qubits previously, we find that the sensitivity of the generally used spectral method in phase qubits is not sufficient to evaluate the exact form of the coupling. On the contrary, our numerical calculation shows that the coupling strength changes remarkably with the flux bias for a flux qubit, providing a useful tool to investigate the coupling mechanism between the two-level systems and qubits.

Processing Quantum Information in Hybrid Topological Qubit and Superconducting Flux Qubit System

  1. Zhen-Tao Zhang,
  2. and Yang Yu
A composite system of Majorana-hosted semiconductor nanowire and superconducting flux qubit is inves- tigated. It is found that the coupling between these two subsystems can be controlled
electrically, supplying a convenient method to implement {pi}/8 phase gate of a Majorana-based topological qubit. We also present a scheme to transfer information from the flux qubit to the topological qubit using Landau-Zener transition. In addition, a structure named top-flux-flux is proposed to retrieve the information stored in the topological qubit. With the demonstration of the entanglement of two topological qubits, it is very promising to do quantum information process with this hybrid system.