https://doi.org/10.1140/epjqt/s40507-024-00273-7
Research
Quantum null-hypothesis device-independent Schmidt number witness
1
Departament de Fisica and Institut d’Aplicacions Computacionals de Codi Comunitari (IAC3), Campus UIB, E-07122, Palma de Mallorca, Balearic Islands, Spain
2
CRISP – Centre de Recerca Independent de sa Pobla, 07420, sa Pobla, Balearic Islands, Spain
3
Faculty of Physics, University of Warsaw, ul. Pasteura 5, PL02-093, Warsaw, Poland
4
Systems Research Institute, Polish Academy of Sciences, 6 Newelska Street, PL01-447, Warsaw, Poland
5
Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, 18 Bartycka Street, PL00-716, Warsaw, Poland
6
Center of Excellence in Artificial Intelligence, AGH University, 30 Mickiewicza Lane, PL30-059, Cracow, Poland
Received:
25
July
2024
Accepted:
13
September
2024
Published online:
27
September
2024
We investigate the dimensionality of bipartite quantum systems by construction of a device-independent null witness test. This test assesses whether a given bipartite state conforms with the expected quantum dimension, Schmidt number, and distinguishes between real and complex spaces. By employing local measurements on each party, the proposed method aims to determine the minimal rank. By performing an experimental demonstration on IBM Quantum devices, we prove the exceptional accuracy of the test and its usefulness in diagnostics beyond routine calibrations. One of the tests shows agreement with theoretical expectations within statistical errors. However, the second test failed by more than 6 standard deviations, indicating unspecified parasitic entanglements, with no known simple origin.
Key words: Quantum dimension / Entanglement / Null witness
© The Author(s) 2024
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