Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlocal Variable-Strength Measurements of N Qubits Using GHZ-like
  Entanglement   The direct measurement of nonlocal properties of entangled quantum systems
has been the subject of several recent experimental investigations. Of
particular interest is the implementation of nonlocal measurements via indirect
measurement schemes, which allow for greater flexibility in the control of the
measurement strength. Building on previous results established in the bipartite
case, we present a scheme to implement genuine nonlocal measurements of N-qubit
systems with variable strength, using GHZ-like entangled qubit meters. This
method can be applied to the joint measurement of commuting product
observables, enabling us to distinguish between orthogonal nonlocal states,
such as Bell states, with minimal disturbance and arbitrary resolution. An
explicit relation between the overall measurement strength and the meter
entanglement as quantified by the $n$-tangle is derived, opening the door to a
new interpretation of the $n$-tangle as a resource for nonlocal measurements.

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The categories of this paper are: math-ph
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The categories of this paper are: eess
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg