Beating the limits with initial correlations
: Daniel Basilewitsch, Rebecca Schmidt, Dominique Sugny, Sabrina Maniscalco, Christiane P. Koch
Publisher: Institute of Physics Publishing
: 2017
New Journal of Physics
: New Journal of Physics
: 19
: 11
: 16
: 1367-2630
DOI: https://doi.org/10.1088/1367-2630/aa96f8
: 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.
quantum control, state preparation, superconducting qubits