Classical correlation and quantum discord in critical systems

By Marcelo S. Sarandy. 2009

450 citations recorded by the source corpus.

We discuss the behavior of quantum and classical pairwise correlations in critical systems, with the quantumness of the correlations measured by the quantum discord. We analytically derive these correlations for general real density matrices displaying ${Z}_{2}$ symmetry. As an illustration, we analyze both the $XXZ$ and the transverse field Ising models. Finite size as well as infinite chains are investigated and the quantum criticality is discussed. Moreover, we identify the spin functions that govern the correlations. As a further example, we also consider correlations in the Hartree-Fock ground state of the Lipkin-Meshkov-Glick model. It is then shown that both classical correlation and quantum discord exhibit signatures of the quantum phase transitions.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/1fbba6c1005aad2c46c3483e9e2fdec45fee6c08

How researchers see this paper

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In Artificial Intelligence

1. Kavan Modi
2. Tomasz Paterek
3. H. Cable
4. Aharon Brodutch
5. Vlatko Vedral

In Atomic and Molecular Physics, and Optics

1. Kavan Modi
2. Tomasz Paterek
3. H. Cable
4. Aharon Brodutch
5. Vlatko Vedral

Citations in the corpus

• The classical-quantum boundary for correlations: Discord and related measures (2011, background): “In a different study, (Sarandy, 2009) considers an Ising model and shows that the derivatives of discord display the characteristic (logarithmic) divergence of the critical Ising model.”