Device-independent certification of degeneracy-breaking measurements

Pan, Alok Kumar (2023) Device-independent certification of degeneracy-breaking measurements. Physical Review A, 107 (2). 022204. ISSN 2469-9926

[img] Text
PhysRevA.107.022204.pdf - Published Version

Download (619kB)


In a device-independent Bell test, the devices are considered to be black boxes and the dimension of the system remains unspecified. The dichotomic observables involved in such a Bell test can be degenerate and one may invoke a suitable measurement scheme to lift the degeneracy. However, the standard Bell test cannot account for whether or up to what extent the degeneracy is lifted, as the effect of lifting the degeneracy can only be reflected in the postmeasurement states, which the standard Bell tests do not certify. In this work, we demonstrate the device-independent certification of degeneracy-breaking measurement based on the sequential Bell test by multiple observers who perform degeneracy-breaking unsharp measurements characterized by positive-operator-valued measures (POVMs) - the noisy variants of projectors. The optimal quantum violation of Clauser-Horne-Shimony-Holt inequality by multiple sequential observers eventually enables us to certify up to what extent the degeneracy has been lifted. In particular, our protocol certifies the upper bound on the number of POVMs used for performing such measurements along with the entangled state and measurement observables. We use an elegant sum-of-squares approach that powers such certification of degeneracy-breaking measurements.

[error in script]
IITH Creators:
IITH CreatorsORCiD
Pan, Alok Kumar
Item Type: Article
Uncontrolled Keywords: Bell test; Black boxes; Breakings; Clauser-Horne-Shimony-Holt inequality; Independent certification; Measurement-based; Multiple observers; Positive-operator-valued measures; Post-measurement; Upper Bound; Quantum entanglement; Bells
Subjects: Physics
Divisions: Department of Physics
Depositing User: Mr Nigam Prasad Bisoyi
Date Deposited: 22 Aug 2023 05:47
Last Modified: 22 Aug 2023 05:47
Publisher URL:
OA policy:
Related URLs:

Actions (login required)

View Item View Item
Statistics for RAIITH ePrint 11608 Statistics for this ePrint Item