# Research

## Recent highlights

We showed that the surface of Weyl semimetals can turn superconducting while the bulk remains metallic, contrary to naïve intuition that higher dimensionality favors spontaneous symmetry breaking. Learn some more

We studied proximity-induced superconductivity in 1D metals with a mismatch in the dispersions of left and right movers and discovered a host of exotic phenomena, such as a perfect superconducting diode effect and charge non-conservation resembling - but distinct from - chiral gauge anomalies. Learn some more

We studied disordered 1D metals where the bands contain a mismatch between left- and right-movers and stumbled upon a new regime of weak localization and counterintuitive indications of robustness to finite-size effects due to the mismatch. Learn some more

We extended the chiral vortical effect - defined as an axial current driven by rotation in chiral fluids and first discovered in high-energy physics for Weyl fermions - to general crystalline solids, introduced a closely related "gyrotropic vortical effect," and proposed electrical and thermal devices that harness these effects. Learn some more

We studied superconducting vortices in time-reversal symmetric Weyl semimetals and discovered exotic behaviors such as non-local Majorana fermions, tunable supersymmetry and transmutable vortex statistics when the vortex is naïvely gapless, and derived a criterion for the presence of Majorana fermions at the ends of gapped vortices that rely only on the Fermi arc connectivity on the surface and the locations of the bulk Weyl nodes. Learn some more

We discovered an entanglement-based signature, namely, the absence of Friedel oscillations in the entanglement entropy profile, of the newly discovered intrinsically gapless topological phases in 1D. Learn some more

We showed that the surface conductivity of Weyl semimetals contains an anomalous contribution stemming from the topological surface-bulk coupling in addition to a Drude contribution from the Fermi arcs. The surface-bulk coupling also bestows the surface with Luttinger arcs in addition to Fermi arcs. The former transforms into the latter upon peeling off suitable layers and therefore lend themselves to convenient experimental detection. Learn some more

We constructed a 1D ladder model that has close parallels with magic-angle graphene but is far easier to study owing to its lower dimensionality, and found a ferromagnetic insulator ground state at half-filling in the quasi-flat band regime. Learn some more

We devised a polynomial-time algorithm to simulate finite temperature properties of non-integrable many-body quantum systems by relying on the eigenstate thermalization hypothesis, whereas brute force exact diagonalization has exponential complexity. Learn some more

We proposed an unusual state of matter that breaks time-reversal symmetry yet lacks magnetism and proved its existence in 1D. Learn some more

We found that bulk β-PdBi2 shows signatures consistent with trivial and topological superconductivity for different levels of potassium doping, possibly making it the first bulk material to possess a topological phase transition inside the superconducting phase. We also discovered a general diagnostic of topological superconductivity in the temperature dependence of the Meissner effect. Learn some more