Updates are available Erratum dated 2014-05-28

Article History

Received: 11 August 2013

Accepted: 10 March 2014

First Online: 20 April 2014

Change Date: 20 April 2014

Change Type: Erratum

Change Details: In the version of this Letter originally published in print, the following mathematical expressions were formatted incorrectly. On page 1, column 1, paragraph 2, line 2, the two symbols "N" should not be superscripted relative to the symbol "⊗". The correct expression is (|0〉⊗N + |1〉⊗N)/√2. Similarly, equation (1) should appear as |ϕ±N,m〉 = (|GHZ+m〉⊗N ±|GHZ−m〉⊗N)/√2. On page 1, column 2, paragraph 1, line 3, the two symbols “m” should not be superscripted relative to the symbol "⊗". The correct expression is (|0〉⊗m ± |1〉⊗m)/√2. In equation (2), the two symbols “3” should not be superscripted relative to the symbol "⊗". The correct expression is |ϕ+3,2〉 = (|Φ+〉⊗3 + |Φ−〉⊗3)/√2 = (|HHHHHH〉 + |HHVVVV〉 + |VVVVHH〉 + |VVHHVV〉)231456/2. In the expression for Uθ appearing on page 4, column 1, paragraph 3, line 5, the symbol "y" should be subscripted relative to the symbol "σ". The correct expression is Uθ = InlineEquation removed. These typographical errors have been corrected in both the HTML and PDF versions of this Letter.

Competing interests

: The authors declare no competing financial interests.