Realization of a Binary-Outcome Projection Measurement of a Three-Level Superconducting Quantum System

Markus Jerger (1) , Pascal Macha (1) , Andrés Rosario Hamann (1) , Yarema Reshitnyk (2) , Kristinn Juliusson (3) , Arkady Fedorov (1, 2)

1 ARC CEED - ARC Centre of Excellence for Environmental Decisions
2 UQ [All campuses : Brisbane, Dutton Park Gatton, Herston, St Lucia and other locations] - The University of Queensland
3 QUANTRONICS - Quantronics Group

Binary-outcome measurements allow to determine whether a multi-level quantum system is in a certain state while preserving quantum coherence between all orthogonal states. In this paper, we explore different regimes of the dispersive readout of a three-level superconducting quantum system coupled to a microwave cavity in order to implement binary-outcome measurements. By designing identical cavity frequency shifts for the first and second excited states of the system, we realize strong projective binary-outcome measurements onto its ground state with a fidelity of 94.3%. Complemented with standard microwave control and low-noise parametric amplification, this scheme enables the quantum non-demolition detection of leakage errors and can be used to create sets of compatible measurements to reveal the contextual nature of superconducting circuits.

Domaines: Physique [physics]; Physique Quantique [quant-ph]

Markus Jerger, Pascal Macha, Andrés Rosario Hamann, Yarema Reshitnyk, Kristinn Juliusson, et al.. Realization of a Binary-Outcome Projection Measurement of a Three-Level Superconducting Quantum System. Physical Review Applied, 2016, 6, pp.014014. ⟨10.1103/PhysRevB.86.180504⟩. ⟨cea-01550811⟩