Abstract: In this talk, I will briefly review the quantum phase transitions in 3D Dirac systems upon switching either attractive or repulsive interactions on. Then, I will discuss some condensed matter systems where these phenomena might be experimentally visualized. Finally, I will present the results of our quantum Monte Carlo simulations for single Dirac fermion systems which can guide some ongoing efforts on conformal bootstrap approaches in 3D

Abstract: In this talk, I will briefly review the quantum electronic cavity systems. I will then move on to introducing a theory to describe strong light-matter interactions between electrons in a crystal and a "sub-wavelength" cavity. In these cavities, polaritons enable to confinement of EM fields at a length scale smaller than that imposed by the free-space diffraction limit. I will discuss how our theory, which is based on EM Green's functions and Feynman diagrammatic techniques for the many-body problem, provides quantitative results on how sub-wavelength polaritons modify the electrical transport properties of an interacting many-fermion system. These modifications are intrinsic (i.e. unrelated to disorder) and occur in the passive regime, in which the cavity is not optically pumped.

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Abstract: In this talk, we explore the intrinsic and extrinsic orbital Hall effects (OHE) in bilayer transition metal dichalcogenides (TMDs) using quantum kinetic theory. These materials, while naturally inversion symmetric, can have their symmetry broken by applying a perpendicular electric field, making them ideal for studying symmetry-driven transport phenomena. We show that extrinsic contributions to the OHE—arising from short-range disorder—become dominant slightly away from the band edges and are significantly enhanced when inversion symmetry is broken. This enhancement results from the activation of both diagonal and off-diagonal components of the orbital angular momentum response. Our findings suggest that even weak inversion symmetry breaking can lead to a strong extrinsic OHE, highlighting bilayer TMDs as tunable platforms for orbital transport in two-dimensional systems