Scientific Reports (Jun 2017)

Minimal control power of controlled dense coding and genuine tripartite entanglement

  • Changhun Oh,
  • Hoyong Kim,
  • Kabgyun Jeong,
  • Hyunseok Jeong

DOI
https://doi.org/10.1038/s41598-017-03822-6
Journal volume & issue
Vol. 7, no. 1
pp. 1 – 8

Abstract

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Abstract We investigate minimal control power (MCP) for controlled dense coding defined by the channel capacity. We obtain MCPs for extended three-qubit Greenberger-Horne-Zeilinger (GHZ) states and generalized three-qubit W states. Among those GHZ states, the standard GHZ state is found to maximize the MCP and so does the standard W state among the W-type states. We find the lower and upper bounds of the MCP and show for pure states that the lower bound, zero, is achieved if and only if the three-qubit state is biseparable or fully separable. The upper bound is achieved only for the standard GHZ state. Since the MCP is nonzero only when three-qubit entanglement exists, this quantity may be a good candidate to measure the degree of genuine tripartite entanglement.