Fusing multiple W states simultaneously with a Fredkin gate

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Özaydın F., Bugu S., Yeşilyurt C., Altıntaş A. A., Tame M., Özdemir Ş. K.

PHYSICAL REVIEW A, vol.89, pp.1-7, 2014 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 89
  • Publication Date: 2014
  • Journal Name: PHYSICAL REVIEW A
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.1-7
  • Istanbul University Affiliated: No

Abstract

We propose an optical scheme to prepare large-scale entangled networks of W states. The scheme works by simultaneously fusing three polarization-encoded W states of arbitrary size via accessing only one qubit of each W state. It is composed of a Fredkin gate (controlled-swap gate), two fusion gates [as proposed in S. K. Ozdemir et al., New J. Phys. 13, 103003 (2011)], and an H-polarized ancilla photon. Starting with three n-qubit W states, the scheme prepares a new W state with 3(n−1) qubits after postselection if both fusion gates operate successfully, i.e., a fourfold coincidence at the detectors. The proposed scheme reduces the cost of creating arbitrarily large W states considerably when compared to previously reported schemes.