Phonon-induced relaxation and decoherence times of the hybrid qubit in silicon quantum dots

E. Ferraro, M. Fanciulli, and M. De Michielis
Phys. Rev. B 100, 035310 – Published 19 July 2019

Abstract

We study theoretically the phonon-induced relaxation and decoherence processes in the hybrid qubit in silicon. A hybrid qubit behaves as a charge qubit when the detuning is close to zero and as a spin qubit for large detuning values. It is realized starting from an electrostatically defined double quantum dot where three electrons are confined and manipulated through only electrical tuning. By employing a three-level effective model for the qubit and describing the environment bath as a series of harmonic oscillators in the thermal equilibrium states, we extract the relaxation and decoherence times as a function of the bath spectral density and of the bath temperature using the Bloch-Redfield theory. For Si quantum dots the energy dispersion is strongly affected by the physics of the valley, i.e., the conduction band minima, so we also included the contribution of the valley excitations in our analysis. Our results offer fundamental information on the system decoherence properties when the unavoidable interaction with the environment is included and temperature effects are considered.

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  • Received 3 April 2019
  • Revised 3 July 2019

DOI:https://doi.org/10.1103/PhysRevB.100.035310

©2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsQuantum Information, Science & Technology

Authors & Affiliations

E. Ferraro1,*, M. Fanciulli1,2, and M. De Michielis1,†

  • 1CNR-IMM Agrate Unit, Via Camillo Olivetti 2, 20864 Agrate Brianza (Province of Monza and Brianza), Italy
  • 2Dipartimento di Scienza dei Materiali, University of Milano Bicocca, Via Roberto Cozzi, 55, 20126 Milano, Italy

  • *elena.ferraro@mdm.imm.cnr.it
  • marco.demichielis@mdm.imm.cnr.it

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Issue

Vol. 100, Iss. 3 — 15 July 2019

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