Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Semi-device independent certification of multiple unsharpness parameters
  through sequential measurements   Based on a sequential communication game, semi-device independent
certification of an unsharp instrument has recently been demonstrated
[\href{https://iopscience.iop.org/article/10.1088/1367-2630/ab3773}{New J.
Phys. 21 083034 (2019),
}\href{https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.033014}{
Phys. Rev. Research 2, 033014 (2020)}]. In this paper, we provide semi-device
independent self-testing protocols in the prepare-measure scenario to certify
multiple unsharpness parameters along with the states and the measurement
settings. This is achieved through the sequential quantum advantage shared by
multiple independent observers in a suitable communication game known as
parity-oblivious random-access-code. We demonstrate that in 3-bit
parity-oblivious random-access-code, at most three independent observers can
sequentially share quantum advantage. The optimal pair (triple) of quantum
advantages enables us to uniquely certify the qubit states, the measurement
settings, and the unsharpness parameter(s). The practical implementation of a
given protocol involves inevitable losses. In a sub-optimal scenario, we derive
a certified interval within which a specific unsharpness parameter has to be
confined. We extend our treatment to the 4-bit case and show that at most two
observers can share quantum advantage for the qubit system. Further, we provide
a sketch to argue that four sequential observers can share the quantum
advantage for the two-qubit system, thereby enabling the certification of three
unsharpness parameters.

9
The categories of this paper are: nlin
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat