Real-time observation of charge states and energy relaxation in a double quantum dot

Toshiaki Hayashi, Toshimasa Fujisawa, Ritsuya Tomita, Yoshiro Hirayama

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We performed real-time observation of charge states in a double quantum dot (QD) by monitoring the current passing through an adjacent quantum point contact (QPC). The position of the QPC was chosen in such a way that the Coulomb coupling of the QPC to one QD is made stronger than to the other QD, so that the QPC current can clearly resolve the charge states of the double QD. With a response time of ∼200 μs, we also investigated the energy relaxation time T1 of the double QD by applying rectangular voltage pulses to the double QD. We confirmed that T1 can be made sufficiently longer than the response time of the QPC.

Original languageEnglish
Pages (from-to)3629-3632
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number4 B
Publication statusPublished - 2006 Apr 25
Externally publishedYes


  • Charge qubit
  • Double quantum dot
  • Energy relaxation
  • Quantum point contact
  • Single-charge detection

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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