Quantum Correlations in NMR Systems

Abstract

In conventional NMR experiments, the Zeeman energy gaps of the nuclear spin ensembles are much lower than their thermal energies, and accordingly exhibit tiny polarizations.Generally such low-purity quantum states are devoid of quantum entanglement. However, there exist certain nonclassical correlations which can be observed even in such systems. In this chapter, we discuss three such quantum correlations, namely, quantum contextuality, Leggett-Garg temporal correlations, and quantum discord. In each case, we provide a brief theoretical background and then describe some results from NMR experiments. * mahesh.ts@iiserpune.ac.in † sudheer.kumar@students.iiserpune.ac.in ‡ uday.bhosale@iiserpune.ac.in arXiv:1608.06579v1 [quant-ph] 5 Aug 2016 'Correlations cry out for explanation' -J. S. Bell in Speakable and Unspeakable in Quantum Mechanics, Cambridge university press (1989).

Experimental demonstration of the violations of Mermin’s and Svetlichny’s inequalities for W and GHZ states

“…Experimental violation of Svetlichny's inequality has been explicated for three-photon GHZ states using photonic system [22]. Quantum correlations such as quantum contextuality, Leggett-Garg temporal correlations, and quantum discord have been studied in NMR Systems [23]. However, investigation of these inequalities for GHZ-and W-class of states in the current technology of superconducting quantum chip explores a new opportunity to experimentally realize.…”