Measuring Bipartite Quantum Correlations of an Unknown State

Author(s)

Silva, I. A. ^[1] ; Girolami, D. ^[2] ; Auccaise, R. ^[3] ; Sarthour, R. S. ^[4] ; Oliveira, I. S. ^[4] ; Bonagamba, T. J. ^[1] ; deAzevedo, E. R. ^[1] ; Soares-Pinto, D. O. ^[1] ; Adesso, G. ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Paulo - Brazil

^[2] Univ Nottingham, Sch Math Sci, Nottingham NG7 2RD - England

^[3] Empresa Brasileira Pesquisa Agr, BR-22460000 Rio De Janeiro - Brazil

^[4] Ctr Brasileiro Pesquisas Fis, BR-22290180 Rio De Janeiro - Brazil

• Document type: Journal article
• Source: Physical Review Letters; v. 110, n. 14 APR 3 2013.
• Web of Science Citations: 57

Abstract

We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance setup and employing geometric discord, we evaluate the quantum correlations of a state without resorting to prior knowledge of its density matrix. The method is applicable to any 2 circle times d system and provides, in terms of number of measurements required, an advantage over full state tomography scaling with the dimension d of the unmeasured subsystem. The negativity of quantumness is measured as well for reference. We also observe the phenomenon of sudden transition of quantum correlations when local phase and amplitude damping channels are applied to the state. DOI: 10.1103/PhysRevLett.110.140501 (AU)

• FAPESP's process: 12/02208-5 - Quantum information processing via nuclear magnetic resonance
• Grantee: Tito José Bonagamba
• Support type: Regular Research Grants
• FAPESP's process: 09/18354-8 - Dynamics and structure of polymer systems as studied by nuclear magnetic resonance
• Grantee: Eduardo Ribeiro de Azevedo
• Support type: Regular Research Grants
• FAPESP's process: 09/54880-6 - Manipulation of nuclear spins by magnetic and quadrupole resonance techniques
• Grantee: Tito José Bonagamba
• Support type: Regular Research Grants