Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum state cloning using Deutschian closed timelike curves   We show that it is possible to clone quantum states to arbitrary accuracy in
the presence of a Deutschian closed timelike curve (D-CTC), with a fidelity
converging to one in the limit as the dimension of the CTC system becomes
large---thus resolving an open conjecture from [Brun et al., Physical Review
Letters 102, 210402 (2009)]. This result follows from a D-CTC-assisted scheme
for producing perfect clones of a quantum state prepared in a known eigenbasis,
and the fact that one can reconstruct an approximation of a quantum state from
empirical estimates of the probabilities of an informationally-complete
measurement. Our results imply more generally that every continuous, but
otherwise arbitrarily non-linear map from states to states can be implemented
to arbitrary accuracy with D-CTCs. Furthermore, our results show that Deutsch's
model for CTCs is in fact a classical model, in the sense that two arbitrary,
distinct density operators are perfectly distinguishable (in the limit of a
large CTC system); hence, in this model quantum mechanics becomes a classical
theory in which each density operator is a distinct point in a classical phase
space.

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The categories of this paper are: plasm-ph
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int