Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Approximate joint measurement of qubit observables through an
  Arthur-Kelly type model   We consider joint measurement of two and three unsharp qubit observables
through an Arthur-Kelly type joint measurement model for qubits. We investigate
the effect of initial state of the detectors on the unsharpness of the
measurement as well as the post-measurement state of the system. Particular
emphasis is given on a physical understanding of the POVM to PVM transition in
the model and entanglement between system and detectors.Two approaches for
characterizing the unsharpness of the measurement and the resulting measurement
uncertainty relations are considered.The corresponding measures of unsharpness
are connected for the case where both the measurements are equally unsharp. The
connection between the POVM elements and symmetries of the underlying
Hamiltonian of the measurement interaction is made explicit and used to perform
joint measurement in arbitrary directions. Finally in the case of three
observables we derive a necessary condition for the approximate joint
measurement and use it show the relative freedom available when the observables
are non-orthogonal.

9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an