Erratum: Experimental realization of a concatenated Greenberger–Horne–Zeilinger state for macroscopic quantum superpositions

Nature Photon. 8, 364–368 (2014); published online: 20 April 2014; corrected after print: 20 April 2014

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 U_θ 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 U_θ = ${\text{e}}^{i\theta {\sigma }_y}$.

These typographical errors have been corrected in both the HTML and PDF versions of this Letter.