Odd-frequency pairing and Kerr effect in the heavy-fermion superconductor UPt${}_3$

We study the emergence of odd-frequency superconducting pairing in UPt${}_3$. Starting from a tight-binding model accounting for the nonsymmorphic crystal symmetry of UPt${}_3$ and assuming an order parameter in the $E_{2u}$ representation, we demonstrate that odd-frequency pairing arises very generally, as soon as inter-sublattice hopping or spin-orbit coupling is present. We also show that in the low temperature superconducting $B$ phase, the presence of a chiral order parameter together with spin-orbit coupling, leads to additional odd-frequency pair amplitudes not present in the $A$ or $C$ phases. Furthermore, we show that a finite Kerr rotation in the $B$ phase is only present if odd-$\omega$ pairing also exists.