Measurement of the Josephson Junction Phase Qubits by a Microstrip Resonator

TL;DR

This paper introduces a novel quasiclassical method for measuring Josephson junction phase qubits using a microstrip resonator, analyzing both classical and quantum regimes and environmental effects.

Contribution

It presents a new quasiclassical approach based on adiabatic reversals for qubit measurement, extending techniques from magnetic resonance force microscopy to quantum state detection.

Findings

Effective measurement via resonant microwave cavity demonstrated

Both linear and nonlinear resonator behaviors analyzed

Environmental influences on measurement process characterized

Abstract

The process of measurement of a phase qubit by a resonant microwave cavity is considered for various interactions between the qubit and the cavity. A novel quasiclassical approach is described based on adiabatic reversals of the qubit state by an effective field. A similar approach was implemented earlier for the detection of electron and nuclear spins using magnetic resonance force microscopy (MRFM), but this approach has not previously been used for the measurement of a quantum state. Quasiclassical and quantum regimes are described. We consider both linear and nonlinear resonators. The effects of the environment on the process of measurement are also analyzed.