Condensed Matter Seminar: Jonathan Ruhman, MIT, “Odd-parity superconductivity near inversion breaking quantum critical point in one dimension”

In this talk I will discuss how an inversion-breaking quantum critical point affects the ground state of a one-dimensional electronic liquid with repulsive interaction and spin-orbit coupling. I will show that regardless of the interaction strength, the critical fluctuations always lead to a gap in the electronic spin-sector. The origin of the gap is a two-particle backscattering process, which becomes relevant due to renormalization of the Luttinger parameter near the critical point. The resulting spin-gapped state is a one-dimensional version of spin triplet superconductivity. Interestingly, in the case of a ferromagnetic critical point the Luttinger parameter is renormalized in the opposite manner, such that the backscattering process remains irrelevant and therefore the spin-sector remains gapless.