Efficient protocol for qubit initialization with a tunable environment

Loading...
Thumbnail Image
Access rights
openAccess
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal
View/Open full text file from the Research portal
Date
2017-07-14
Major/Subject
Mcode
Degree programme
Language
en
Pages
12
1-12
Series
npj Quantum Information, Volume 3
Abstract
We 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.
Description
Keywords
SUPERCONDUCTING QUANTUM BITS, ERROR-CORRECTION, TRAPPED IONS, STATE, COMPUTATION, AMPLIFICATION, DISSIPATION, CIRCUIT
Other note
Citation
Tuorila , J , Partanen , M , Ala-Nissila , T & Mottonen , M 2017 , ' Efficient protocol for qubit initialization with a tunable environment ' , npj Quantum Information , vol. 3 , 27 , pp. 1-12 . https://doi.org/10.1038/s41534-017-0027-1