title: Experimental activation of bound entanglement.
abstract: Entanglement is one of the essential resources in quantum information and communication technology (QICT). The entanglement thus far explored and applied to QICT has been pure and distillable entanglement. Yet, there is another type of entanglement, called "bound entanglement," which is not distillable by local operations and classical communication. We demonstrate the experimental "activation" of the bound entanglement held in the four-qubit Smolin state, unleashing its immanent entanglement in distillable form, with the help of auxiliary two-qubit entanglement and local operations and classical communication. We anticipate that it opens the way to a new class of QICT applications that utilize more general classes of entanglement than ever, including bound entanglement.
authors.affiliation: Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Kaneda
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Shimizu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishizaka
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Mitsumori
authors.forename: Hideo
authors.initials: H
authors.lastname: Kosaka
authors.forename: Keiichi
authors.initials: K
authors.lastname: Edamatsu