Nature Communications 2: Article number: 272 (2011); Published: 12 April 2011; Updated: 22 May 2012.

This Article contains two typographical errors in the first and second paragraphs of the section entitled 'Diamagnetic response': '〈BxωL/γμ' should be '〈Bx〉=ωL/γμ' and '〈jab〉=〈(1/μ0) dBx/dz〉/≠0' should be '〈jab〉=〈(1/μ0) dBx/dz〉≠0'.