Physical Review AComment on “Quantum convolutional error-correcting codes”Antonio Carlos Aido de Almeida, Reginaldo PalazzoPublished Aug 5, 2005• 2 citationsPublisherAbstractIn this Comment we present a counterexample to theorems 2 and 3 from Chau [Phys. Rev. A 58, 905 (1998)] regarding quantum convolutional codes. © 2005 The American Physical Society.DOI10.1103/physreva.72.026301