Spectroscopy of a Cooper-Pair box in the Autler-Townes configuration

TL;DR

This paper presents a theoretical analysis of a superconducting qubit coupled to an RLC oscillator, revealing Autler-Townes-like spectral features that could aid in qubit characterization without requiring high-frequency measurements.

Contribution

It introduces a novel spectroscopic method using an RLC oscillator as a probe to observe Autler-Townes effects in a superconducting qubit system.

Findings

Frequency splitting features analogous to Autler-Townes effect identified

Spectral features observable in lower frequency bands

Adjustable frequency band for experimental flexibility

Abstract

A theoretical spectroscopic analysis of a microwave driven superconducting charge qubit (Cooper-pair box coupled) to an RLC oscillator model is performed. By treating the oscillator as a probe through the backreaction effect of the qubit on the oscillator circuit, we extract frequency splitting features analogous to the Autler-Townes effect from quantum optics, thereby extending the analogies between superconducting and quantum optical phenomenology. These features are found in a frequency band that avoids the need for high frequency measurement systems and therefore may be of use in qubit characterization and coupling schemes. In addition we find this frequency band can be adjusted to suit an experimental frequency regime by changing the oscillator frequency.