Theory Seminar: Quantum phase transitions between orthogonal and normal fermions in metals and semi-metals

Snir Gazit (Hebrew University)
Orthogonal fermions present the simplest form of electronic fractionalization, where physical (gauge- neutral) electrons split into a local product of spinful fermions and Ising matter fields. 

September 29, 2021

Snir Gazit (Hebrew University)
Group Seminar via Zoom
Wed 29. September 2021, 11:30 am (MEZ)

Abstract:

Orthogonal fermions present the simplest form of electronic fractionalization, where physical (gauge- neutral) electrons split into a local product of spinful fermions and Ising matter fields. This construction naturally gives rise to an emergent Ising gauge structure, which in two space dimensions is potentially topologically ordered. Using sign problem-free quantum Monte Carlo simulations, we investigate a lattice model of orthogonal fermions coupled to Ising gauge fields and matter fields. By tuning microscopic parameters, we control the fractionalization process and establish the resulting phase diagram. In particular, we demonstrate a transition between small and large Fermi surfaces, which crucially does not involve translational symmetry breaking, a phenomenon that violates the conventional Luttinger theorem. In addition, we uncover a new form of a deconfined critical point between phases with conventional and topological orders.

 

Go to Editor View