Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Derivation of the robustness from the concurrence   Adding the maximally mixed state with some weight to the entanglement system
leads to disentanglement of the latter. For each predefined entangled state
there exists a minimal value of this weight for which the system loses its
entanglement properties. These values were proposed to be used as a
quantitative measure of entanglement called robustness [G. Vidal and R.
Tarrach, Phys. Rev. A 59, 141 (1999)]. Using the concurrence, we propose the
derivation of this measure for the system of two-qubit. Namely, for a two-qubit
pure state, an exact expression of robustness is obtained. Finally, in the same
way, the robustness of special cases of mixed two-qubit states is calculated.

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The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: eess
10
The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph