title: Smooth Optimal Quantum Control for Robust Solid-State Spin Magnetometry.
abstract: We experimentally demonstrate a simple yet versatile optimal quantum control technique that achieves tailored robustness against qubit inhomogeneities and control errors while requiring minimal bandwidth. We apply the technique to nitrogen-vacancy (NV) centers in diamond and verify its performance using quantum process tomography. In a wide-field NV center magnetometry scenario, we achieve a homogeneous sensitivity across a 33% drop in control amplitude, and we improve the sensitivity by up to 2 orders of magnitude for a normalized detuning as large as 40%, achieving a value of 20  nT Hz(-1/2) μm(3/2) in sensitivity times square root volume.
authors.affiliation: Vienna Center for Quantum Science and Technology and Atominstitut, Vienna University of Technology (TU Wien), Stadionallee 2, 1020 Vienna, Austria.
authors.forename: Tobias
authors.initials: T
authors.lastname: Nöbauer
authors.affiliation: Vienna Center for Quantum Science and Technology and Atominstitut, Vienna University of Technology (TU Wien), Stadionallee 2, 1020 Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Angerer
authors.affiliation: Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstraße 19, 79104 Freiburg, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Bartels
authors.affiliation: Vienna Center for Quantum Science and Technology and Atominstitut, Vienna University of Technology (TU Wien), Stadionallee 2, 1020 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Trupke
authors.affiliation: Institute for Theoretical Physics, Vienna University of Technology (TU Wien), Wiedner Hauptstraße 8-10/136, 1040 Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Rotter
authors.affiliation: Vienna Center for Quantum Science and Technology and Atominstitut, Vienna University of Technology (TU Wien), Stadionallee 2, 1020 Vienna, Austria.
authors.forename: Jörg
authors.initials: J
authors.lastname: Schmiedmayer
authors.affiliation: Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstraße 19, 79104 Freiburg, Germany.|QOLS, Blackett Laboratory, Imperial College, London SW7 2AZ, United Kingdom.
authors.forename: Florian
authors.initials: F
authors.lastname: Mintert
authors.affiliation: Vienna Center for Quantum Science and Technology and Atominstitut, Vienna University of Technology (TU Wien), Stadionallee 2, 1020 Vienna, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Majer