Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental localisation of quantum entanglement through monitored
  classical mediator   Quantum entanglement is a form of correlation between quantum particles that
cannot be increased via local operations and classical communication. It has
therefore been proposed that an increment of quantum entanglement between
probes that are interacting solely via a mediator implies non-classicality of
the mediator. Indeed, under certain assumptions regarding the initial state,
entanglement gain between the probes indicates quantum coherence in the
mediator. Going beyond such assumptions, there exist other initial states which
produce entanglement between the probes via only local interactions with a
classical mediator. In this process the initial entanglement between any probe
and the rest of the system "flows through" the classical mediator and gets
localised between the probes. Here we theoretically characterise maximal
entanglement gain via classical mediator and experimentally demonstrate, using
liquid-state NMR spectroscopy, the optimal growth of quantum correlations
between two nuclear spin qubits interacting through a mediator qubit in a
classical state. We additionally monitor, i.e., dephase, the mediator in order
to emphasise its classical character. Our results indicate the necessity of
verifying features of the initial state if entanglement gain between the probes
is used as a figure of merit for witnessing non-classical mediator. Such
methods were proposed to have exemplary applications in quantum optomechanics,
quantum biology and quantum gravity.

25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph