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(external)
: https://research.utu.fi/converis/portal/detail/Publication/29504264(external)
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.