A1 Refereed original research article in a scientific journal
Beating the limits with initial correlations
Authors: Daniel Basilewitsch, Rebecca Schmidt, Dominique Sugny, Sabrina Maniscalco, Christiane P. Koch
Publisher: Institute of Physics Publishing
Publication year: 2017
Journal: New Journal of Physics
Journal name in source: New Journal of Physics
Volume: 19
Issue: 11
Number of pages: 16
ISSN: 1367-2630
DOI: https://doi.org/10.1088/1367-2630/aa96f8
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/29504264
Fast and reliable reset of a qubit is a key prerequisite for any quantum technology. For real world open
quantum systems undergoing non-Markovian dynamics, reset implies not only purification, but in
particular erasure of initial correlations between qubit and environment. Here, we derive optimal reset
protocols using a combination of geometric and numerical control theory. For factorizing initial
states, we find a lower limit for the entropy reduction of the qubit as well as a speed limit. The timeoptimal
solution is determined by the maximum coupling strength. Initial correlations, remarkably,
allow for faster reset and smaller errors. Entanglement is not necessary.
Keywords:
quantum control, state preparation, superconducting qubits
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