A Controllable Interaction between Two-Level Systems inside a Josephson Junction

TL;DR

This paper investigates how two-level systems within Josephson junctions can interact via a resonator, enabling potential quantum gate operations, and explores their coherence and controllability for quantum computing applications.

Contribution

It introduces a method to mediate and control interactions between TLS qubits using a driven Josephson junction resonator, advancing quantum gate implementation.

Findings

TLS's can be coherently coupled via a Josephson junction resonator.

The effective interaction enables controlled quantum logic gates.

TLS's exhibit long decoherence times suitable for qubit applications.

Abstract

Two-level system fluctuators (TLS's) in the tunnel barrier of a Josephson junction have recently been demonstrated to cause novel energy splittings in spectroscopic measurements of superconducting phase qubits. With their strong coupling to the Josephson junction and relatively long decoherence times, TLS's can be considered as potential qubits and demonstrate coherent quantum effects. Here, we study the effective interaction between the TLS qubits that is mediated by a Josephson junction resonator driven by an external microwave source. This effective interaction can enable controlled quantum logic gates between the TLS's. Our study can be extended to other superconducting resonators coupling with TLS's.