336 research outputs found
The Existence of Quantum Entanglement Catalysts
Without additional resources, it is often impossible to transform one
entangled quantum state into another with local quantum operations and
classical communication. Jonathan and Plenio [Phys. Rev. Lett. 83, 3566(1999)]
presented an interesting example showing that the presence of another state,
called a catalyst, enables such a transformation without changing the catalyst.
They also pointed out that in general it is very hard to find an analytical
condition under which a catalyst exists. In this paper we study the existence
of catalysts for two incomparable quantum states. For the simplest case of
catalysts for transformations from one state to
another, a necessary and sufficient condition for existence is found. For the
general case, we give an efficient polynomial time algorithm to decide whether
a catalyst exists for two incomparable states, where
is treated as a constant.Comment: 12 pages. Presentation part improved. Main results unchanged.
Essentially the journal versio
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