Retrieving qubit information despite decoherence

Amnon Aharony*, Shmuel Gurvitz, Ora Entin-Wohlman, Sushanta Dattagupta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


The time evolution of a qubit, consisting of two single-level quantum dots, is studied in the presence of telegraph noise. The dots are connected by two tunneling paths with an Aharonov-Bohm flux enclosed between them. Under special symmetry conditions, which can be achieved by tuning gate voltages, there develops partial decoherence: at long times, the off-diagonal element of the reduced density matrix (in the basis of the two dot states) approaches a nonzero value, generating a circulating current around the loop. The flux dependence of this current contains full information on the initial quantum state of the qubit, even at infinite time. Small deviations from this symmetry yield a very slow exponential decay toward the fully decoherent limit. However, the amplitudes of this decay also contain the full information on the initial qubit state, measurable either via the current or via the occupations of the qubit dots.

Original languageEnglish
Article number245417
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number24
StatePublished - 2010
Externally publishedYes


Dive into the research topics of 'Retrieving qubit information despite decoherence'. Together they form a unique fingerprint.

Cite this