Tuorila_Qubit-Initialization_njp.Quant.Information.3.(2017).27.pdf (2.03 MB)
Efficient protocol for qubit initialization with a tunable environment
journal contribution
posted on 2017-09-05, 11:03 authored by Jani Tuorila, Matti Partanen, Tapio Ala-NissilaTapio Ala-Nissila, Mikko MottonenWe propose an efficient qubit initialization protocol based on a dissipative environment that can be dynamically adjusted. Here, the
qubit is coupled to a thermal bath through a tunable harmonic oscillator. On-demand initialization is achieved by sweeping the
oscillator rapidly into resonance with the qubit. This resonant coupling with the engineered environment induces fast relaxation to
the ground state of the system, and a consecutive rapid sweep back to off resonance guarantees weak excess dissipation during
quantum computations. We solve the corresponding quantum dynamics using a Markovian master equation for the reduced
density operator of the qubit-bath system. This allows us to optimize the parameters and the initialization protocol for the qubit.
Our analytical calculations show that the ground-state occupation of our system is well protected during the fast sweeps of the
environmental coupling and, consequently, we obtain an estimate for the duration of our protocol by solving the transition rates
between the low-energy eigenstates with the Jacobian diagonalization method. Our results suggest that the current experimental
state of the art for the initialization speed of superconducting qubits at a given fidelity can be considerably improved.
Funding
This work was supported by the Academy of Finland through its Centers of Excellence Programme under grant numbers 251748 and 284621, and through grant number 305306. We also acknowledge funding from the European Research Council under Consolidator Grant number 681311 (QUESS) and from the Vilho, Yrjo, and Kalle Vaisala Foundation.
History
School
- Science
Department
- Mathematical Sciences
Published in
npj Quantum InformationVolume
3Issue
1Citation
TOURILA, J. ...et al., 2017. Efficient protocol for qubit initialization with a tunable environment. npj Quantum Information, 3: 27.Publisher
© the Authors. Published by the Nature Publishing GroupVersion
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/Acceptance date
2017-06-15Publication date
2017Notes
This is an Open Access Article. It is published by Nature Publishing Group under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/ISSN
2056-6387eISSN
2056-6387Publisher version
Language
- en