Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Purification of Single Qubits and reconstruction from Post-Measurement
  State   Purification of mixed states in Quantum Mechanics, by which we mean the
transformation into pure states, has been viewed as an {\it Operation} in the
sense of Kraus et al and explicit {\it Kraus Operators} \cite{kra1,kra2,kra3}
have been constructed for two seperate purification protocols. The first one,
initially due to Schrodinger \cite{sch} and subsequently elaborated by
Sudarshan et al \cite{sudar}, is based on the {\it preservation of
probabilities}. We have constructed a second protocol here based on {\it
optimization of fidelities}. Both purification protocols have been implemented
on a single qubit in an attempt to improve the fidelity of the purified post
measurement state of the qubit with the initial pure state. We have considered
both {\it complete} and {\it partial} measurements and have established bounds
and inequalities for various fidelities. We show that our purification protocol
leads to better state reconstruction, most explicitly so, when partial
measurements are made.

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The categories of this paper are: gr-qc
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The categories of this paper are: eess
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
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The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an