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Coherent quantum oscillations and echo measurements of a Si charge qubit

Research output: Contribution to journalJournal article

Published

  • Zhan Shi
  • C. B. Simmons
  • Daniel R. Ward
  • Jonathan Prance
  • R. T. Mohr
  • Teck Seng Koh
  • John King Gamble
  • Xian Wu
  • D. E. Savage
  • M. G. Lagally
  • Mark Friesen
  • S. N. Coppersmith
  • M. A. Eriksson
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Journal publication date13/08/2013
JournalPhysical Review B
Journal number7
Volume88
Number of pages6
Original languageEnglish

Abstract

Fast quantum oscillations of a charge qubit in a double quantum dot fabricated in a Si/SiGe heterostructure are demonstrated and characterized experimentally. The measured inhomogeneous dephasing time T2* ranges from 127 ps to 2.1 ns; it depends substantially on how the energy difference of the two qubit states varies with external voltages, consistent with a decoherence process that is dominated by detuning noise (charge noise that changes the asymmetry of the qubit's double-well potential). In the regime with the shortest T2*, applying a charge-echo pulse sequence increases the measured inhomogeneous decoherence time from 127 to 760 ps, demonstrating that low-frequency noise processes are an important dephasing mechanism.

Bibliographic note

©2013 American Physical Society