Theoretical analysis of continuously driven dissipative solid-state qubits

TL;DR

This paper provides a theoretical analysis of driven solid-state qubits, combining numerical and analytical methods to explore nonlinear effects and spectral features beyond idealized models, with implications for experimental spectroscopy.

Contribution

It introduces a realistic model for driven qubits that accounts for non-orthogonal driving and static terms, extending beyond the rotating-wave approximation.

Findings

Identification of nonlinear driving effects in solid-state qubits

Analysis of spectroscopy peak widths and shifts beyond Bloch-Siegert predictions

Limitations of NMR linewidth formulas at low temperatures

Abstract

We study a realistic model for driven qubits using the numerical solution of the Bloch-Redfield equation as well as analytical approximations using a high-frequency scheme. Unlike in idealized rotating-wave models suitable for NMR or quantum optics, we study a driving term which neither is orthogonal to the static term nor leaves the adiabatic energy value constant. We investigate the underlying dynamics and analyze the spectroscopy peaks obtained in recent experiments. We show, that unlike in the rotating-wave case, this system exhibits nonlinear driving effects.We study the width of spectroscopy peaks and show, how a full analysis of the parameters of the system can be performed by comparing the first and second resonance. We outline the limitations of the NMR linewidth formula at low temperature and show, that spectrocopic peaks experience a strong shift which goes much beyond the Bloch-Siegert shift of the Eigenfrequency.