title: Experimental demonstration of quantum state expansion in a cluster of dipolar-coupled nuclear spins.
abstract: It is experimentally demonstrated that an arbitrary quantum state of a single spin 1/2, a| upward arrow+b| downward arrow, can be converted into a superposition of the two ferromagnetic states of a spin cluster: a| upward arrow upward arrow... upward arrow upward arrow+b| downward arrow downward arrow... downward arrow downward arrow. The physical system is a cluster of seven dipolar-coupled nuclear spins of single-labeled 13C-benzene molecules in a liquid-crystalline matrix. In this complex system, the pseudopure ground state and the required controlled unitary transformations have been implemented. The experimental scheme can be considered as an explicit model of quantum measurement.
authors.affiliation: Department of Chemistry, Kent State University, Kent, Ohio 44242-0001, USA.
authors.forename: Jae-Seung
authors.initials: JS
authors.lastname: Lee
authors.forename: A K
authors.initials: AK
authors.lastname: Khitrin