Fermion-bag approach to interacting Hamiltonian lattice fermions

In contrast to traditional Lagrangian lattice field theories, the Hamiltonian formulation provides an alternate approach to study strongly coupled four-fermion models, Hamiltonians have reduced doubling, preserve more symmetries and recent developments suggest the presence of new solutions to sign problems. Hamiltonian lattice field theories can be formulated both in discrete and continuous times while preserving all these advantages. We apply the Hamiltonian approach to compute the critical exponents of the 2+1d Gross-Neveu model with Nf=1 (4-component) Dirac fermions which was impossible so far in Lagrangian lattice field theory. Using ideas of fermion bags we argue that we can perform these calculations on much larger lattices than was possible until now.