Effects of quasiparticle tunnelling in a circuit-QED realization of a strongly driven two-level system
Artikel i vetenskaplig tidskrift, 2013

We experimentally and theoretically study the frequency shift of a driven cavity coupled to a superconducting charge qubit. In addition to previous studies, here we also consider drive strengths large enough to energetically allow for quasiparticle creation. Quasiparticle tunnelling leads to the inclusion of more than two charge states in the dynamics. To explain the observed effects, we develop a master equation for the microwave dressed charge states, including quasiparticle tunnelling. A bimodal behaviour of the frequency shift as a function of gate voltage can be used for sensitive charge detection. However, at weak drives, the charge sensitivity is significantly reduced by nonequilibrium quasiparticles, which induce transitions to a non-sensitive state. Unexpectedly, at high-enough drives, the quasiparticle tunnelling enables a very fast relaxation channel to the sensitive state. In this regime, the charge sensitivity is thus robust against externally injected quasiparticles and the desired dynamics prevail over a broad range of temperatures. We find very good agreement between the theory and experiment over a wide range of drive strengths and temperatures.

relaxation

dynamics

quantum

Författare

Juha Leppäkangas

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

Sebastian Erik de Graaf

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Astghik Adamyan

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Mikael Fogelström

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

Andrey Danilov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Tobias Lindström

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Sergey Kubatkin

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Göran Johansson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

Journal of Physics B: Atomic, Molecular and Optical Physics

0953-4075 (ISSN)

Vol. 46 22 Art. no. 224019-

Ämneskategorier

Atom- och molekylfysik och optik

DOI

10.1088/0953-4075/46/22/224019

Mer information

Skapat

2017-10-06