Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cloning of Quantum Entanglement   Quantum no-cloning, the impossibility of perfectly cloning an arbitrary
unknown quantum state, is one of the most fundamental limitations due to the
laws of quantum mechanics, which underpin the physical security of quantum key
distribution. Quantum physics does allow, however, approximate cloning with
either imperfect state fidelity and/or probabilistic success. Whereas
approximate quantum cloning of single-particle states has been tested
previously, experimental cloning of quantum entanglement -- a highly
non-classical correlation -- remained unexplored. Based on a multiphoton linear
optics platform, we demonstrate quantum cloning of two photon entangled states
for the first time. Remarkably our results show that one maximally entangled
photon pair can be broadcast into two entangled pairs, both with state
fidelities above 50\%. Our results are a key step towards cloning of complex
quantum systems, and are likely to provide new insights into quantum
entanglement.

34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
18
The categories of this paper are: econ
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an