Coherent Josephson phase qubit with a single crystal silicon capacitor

TL;DR

This paper presents a Josephson phase qubit with a single crystal silicon capacitor, achieving significantly longer energy relaxation times due to lower dielectric loss, and demonstrating scalability for larger quantum circuits.

Contribution

Introduction of a single crystal silicon capacitor into a Josephson phase qubit, resulting in improved coherence times and scalable design for quantum computing.

Findings

T1 times up to 1.6 microseconds achieved

Significant reduction in dielectric loss compared to amorphous materials

Design scalable to multi-qubit integrated circuits

Abstract

We have incorporated a single crystal silicon shunt capacitor into a Josephson phase qubit. The capacitor is derived from a commercial silicon-on-insulator wafer. Bosch reactive ion etching is used to create a suspended silicon membrane; subsequent metallization on both sides is used to form the capacitor. The superior dielectric loss of the crystalline silicon leads to a significant increase in qubit energy relaxation times. T1 times up to 1.6 micro-second were measured, more than a factor of two greater than those seen in amorphous phase qubits. The design is readily scalable to larger integrated circuits incorporating multiple qubits and resonators.