Device-independent dimension leakage null test on qubits at low operational cost

Abstract

We construct a null test of the two-level space of a qubit, which is both device independent and needs a small number of different experiments. We demonstrate its feasibility on IBM Quantum, with most qubits failing the test by more than 10 standard deviations. The robustness of the test against common technical imperfections, like decoherence and phase shifts, and supposedly negligible leakage, indicates that the origin of deviations is beyond known effects.

7 pages, 4 figures

References in corpus (8)

• Simple pulses for elimination of leakage in weakly nonlinear qubits
• Device-independent tests of classical and quantum dimensions
• Analytic control methods for high fidelity unitary operations in a weakly nonlinear oscillator
• Dimension witnesses and quantum state discrimination
• Optimal classical and quantum real and complex dimension witness
• Precise certification of a qubit space
• Leakage in restless quantum gate calibration
• Quantum dimension witness with a single repeated operation