Efficient protocol for qubit initialization with a tunable environment

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • University of Oulu
  • University of Jyväskylä
  • Loughborough University
  • Brown University

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.

Details

Original languageEnglish
Article number27
Pages (from-to)1-12
Number of pages12
Journalnpj Quantum Information
Volume3
Publication statusPublished - 14 Jul 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • SUPERCONDUCTING QUANTUM BITS, ERROR-CORRECTION, TRAPPED IONS, STATE, COMPUTATION, AMPLIFICATION, DISSIPATION, CIRCUIT

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