Does a Kalb--Ramond field make spacetime optically active? Sayan Kar, Parthasarathi Majumdar, Soumitra SenGupta and Aninda Sinha Eur. Phys. J. C, 23 2 (2002) 357-361 Published online: 15 March 2002 DOI: 10.1007/s100520100872