UMR 5672

logo de l'ENS de Lyon
logo du CNRS
You are here: Home / Seminars / Theoretical Physics / Quantizing driven superconducting circuits: drive-induced nonlinear enhancements to the Purcell effect and the measurement problem

Quantizing driven superconducting circuits: drive-induced nonlinear enhancements to the Purcell effect and the measurement problem

Alex Petrescu (Université de Sherbrooke, Québec)
When Feb 11, 2021
from 04:00 to 05:00
Where visioconférence
Attendees Alex Petrescu
Add event to calendar vCal
iCal

Jeudi 11 Février

 

Title: Quantizing driven superconducting circuits: drive-induced nonlinear enhancements to the Purcell effect and the measurement problem

 Alex Petrescu (Université de Sherbrooke, Québec)

 

Abstract:  

With current advances in state preparation, as well as gate and measurement operations, superconducting circuits are now a leading architecture for quantum information processing. As these systems are scaled up, strict requirements on the fidelity of operations required for computation and readout are imposed. In this talk we focus on the so-called “readout problem” in superconducting circuit quantum electrodynamics: several experiments have shown that qubit energy relaxation rates may become strongly dependent on the power of the measurement drive, even for moderate or weak drives; this hampers efforts to improve readout fidelity. To explain this, we devised a perturbation theory for driven-dissipative, weakly anharmonic, superconducting circuits based on a sequence of unitary transformations. Applied to a transmon qubit coupled to a readout resonator, this approach allows us to classify the nonlinear processes that enhance qubit relaxation in the presence of resonator photons. We will then discuss a more general framework for quantizing driven superconducting circuits, with applications to the study of parametric gates, Josephson parametric amplifiers, and multi-qubit systems.