New class of singlet superconductors which break the time reversal and parity
A class of singlet superconductors with a gap function \ensuremath{\Delta}(k,${\mathrm{\ensuremath{\omega}}}_{\mathit{n}}$) which is odd in both momentum and Matsubara frequency is considered. Some of the physical properties of this superconductivity are discussed and it is argued that in many cases there is no gap in the quasiparticle spectrum and these superconductors will exhibit a Meissner effect.