Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Almost all quantum states have non-classical correlations   Quantum discord quantifies non-classical correlations in a quantum system
including those not captured by entanglement. Thus, only states with zero
discord exhibit strictly classical correlations. We prove that these states are
negligible in the whole Hilbert space: typically a state picked out at random
has positive discord; and, given a state with zero discord, a generic
arbitrarily small perturbation drives it to a positive-discord state. These
results hold for any Hilbert-space dimension, and have direct implications on
quantum computation and on the foundations of the theory of open systems. In
addition, we provide a simple necessary criterion for zero quantum discord.
Finally, we show that, for almost all positive-discord states, an arbitrary
Markovian evolution cannot lead to a sudden, permanent vanishing of discord.

31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga