Realistic quantum manipulation of two-level system fluctuators

TL;DR

This paper proposes a method to implement universal quantum logic gates on two-level system fluctuators in superconducting devices by tuning a superconducting resonator, overcoming energy separation challenges, and demonstrating high-fidelity gates through numerical simulations.

Contribution

It introduces a novel scheme for quantum gate operations on fluctuators using resonator controllability, expanding quantum manipulation capabilities in superconducting systems.

Findings

High-fidelity quantum gates achievable with realistic parameters

Gate operations possible between fluctuators in different Josephson junctions

Numerical simulations confirm robustness against resonator decay

Abstract

Two-level system fluctuators in superconducting devices have demonstrated coherent coupling with superconducting qubits. Here, we show that universal quantum logic gates can be realized in these two-level systems solely by tuning a superconducting resonator in which they are imbedded. Because of the large energy separation between the fluctuators, conventional gate schemes in the cavity QED approach that are widely used for solid-state qubits cannot be directly applied to the fluctuators. We study a scheme to perform the gate operations by exploiting the controllability of the superconducting resonator with realistic parameters. Numerical simulation that takes into account the decay of the resonator mode shows that the quantum logic gates can be realized with high fidelity at moderate resonator decay rate. The quantum logic gates can also be realized between fluctuators inside different Josephson junctions that are connected by a superconducting loop. Our scheme can be applied to explore the coupling between two-level system fluctuators and superconducting resonators as well as the coherent properties of the fluctuators.