Speaker
Description
Superconducting quantum circuits based on Josephson junction arrays have a strong potential in simulating many-body physics. Refined experimental control that has been achieved over superconducting quantum circuits may provide a promising path towards probing exotic phases arising from many-body effects. Among these, Symmetry Protected Topological (SPT) phases are of particular interest since they host protected zero energy modes (ZEM) localized at the edges of an open system. These modes may in turn possibly provide for protected qubits, i.e. immune to external disorder or circuitry, suitable for quantum computing. A prototypical example is the quantum sine-Gordon (QSG) model which exhibits two SPT phases which are dual to each other and are characterized by a doubly degenerate ground state which host exponentially localized phase accumulation at the edges. In this talk I will discuss the design of a superconducting quantum circuit whose low energy degrees of freedom are described by the QSG model. I will demonstrate that by tuning various parameters in the circuit one can probe the QSG model in both the semi-classical regime and the quantum regime. In the quantum regime, the phase accumulations in the two degenerate ground states give rise to super-currents that flow across the circuit elements localized at the two edges. These super-currents are associated with Majorana zero modes (MZM) which are protected by the symmetries of the system, indicating an intriguing possibility of realizing MZM in superconducting quantum circuits.
