Erratum: Experimental observation of optical rotation generated in vacuum by a magnetic field (Physical Review Letters (2006) 96 (110406))

The observed vacuum optical rotation signal reported in [1] has now been excluded by more recent results from the PVLAS Collaboration [2], which show that it was due to an instrumental artifact and was not of physical origin. These new data therefore also exclude the possible interpretation of the signal reported in [1], as caused by the existence of a light, neutral, spin-zero particle.