Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Protecting Two-Qubit Quantum States by $\pi$-Phase Pulses   We study the state decay of two qubits interacted with a common harmonic
oscillator reservoir. There are both decoherence error and the error caused by
the amplitude change of the superradiant state. We show that frequent
$\pi$-phase pulses can eliminate both typpes of errors therefore protect a
two-qubit odd-parity state more effectively than the frequent measurement
method. This shows that the the methods using dynamical decoupling and the
quantum Zeno effects actually can give rather {\em different} results when the
operation frequency is finite.

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The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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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: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex