Beating the limits with initial correlations. (28th November 2017)

• Record Type: Journal Article
• Authors: Basilewitsch, Daniel; Schmidt, Rebecca; Sugny, Dominique; Maniscalco, Sabrina; Koch, Christiane P
• Is Part Of: New journal of physics. Volume 19:Number 11(2017:Nov.)
• Publication Date: 2017-11-28
• Subjects: quantum control -- superconducting qubits -- state preparation; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aa96f8
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: 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 time-optimal solution is determined by the maximum coupling strength. Initial correlations, remarkably, allow for faster reset and smaller errors. Entanglement is not necessary.