CM Seminar - The Left Hand of the Electron in a Chiral Vacuum

The light isotope, 3 He, undergoes BCS condensation below 2 × 10−3 Kelvin. Under a wide range of conditions the ground state (3 He-A) is a condensate of chiral p-wave molecular pairs of 3 He atoms, which spontaneously break parity and time-reversal symmetry. An electron embedded in 3 He-A polarizes the condensate and inherits signatures of the parity-violating vacuum. In particular, electrons embedded in liquid 3 He-A form a self-trapped ion - an “electron bubble” - with a mass, M ≈ 100 m3 , a radius R ≈ 2 nm and an angular momentum, J ≈ 100 h¯ . Experimental signatures include the anomalous Hall effect for electron transport in superfluid 3 He-A, providing a direct detection of parity violation and broken time-reversal symmetry by the chiral ground state of 3 He.1 I present the theory of the anomalous Hall effect for electrons moving in the chiral phase of 3 He, and explain the origin of the transverse force on an electron moving in a chiral vacuum. I discuss some of the implications of the theory of of anomalous transport in chiral superfluids and superconductors.2 1. H. Ikegami, Y. Tsutsumi, & K. Kono, Chiral Symmetry in Superfluid 3 He-A, Science, 341,59–62, 2013. 2. O. Shevtsov & J. A. Sauls, Electrons & Weyl Fermions in Superfluid 3 He-A, Phys. Rev. B, 94, 064511, 2016. 3. V. Ngampruetikorn & J. A. Sauls, Anomalous Thermal Hall Effect in Chiral Superconductors , PRL, 124, 157002 (2020) . † Research supported by NSF grant DMR-1508730.