TNQMP2016: Mari-Carmen Bañuls (June 29, 2016)

Mari-Carmen Bañuls (MPQ)
"Using TNS for Lattice Gauge Theories"

Lattice Gauge Theories, in their Hamiltonian version, offer a challenging scenario for Tensor Network (TN) techniques. While the dimensions and sizes of the systems amenable to TNS studies are still far from those achievable by 4-dimensional systems, TN can be readily used for problems which more standard techniques cannot easily tackle, such as the presence of a chemical potential, or out-of-equilibrium dynamics.
We have explored the performance of Matrix Product States (MPS) in the case of the Schwinger model, as a widely used testbench for lattice techniques, and also in a non-Abelian scenario. Using finite-size, open boundary MPS, we are able to determine low energy states of the model away from any perturbative regime. The precision achieved by the method allows for accurate finite size and continuum limit extrapolations of the ground state energy, but also of the mass gaps and temperature dependent quantities, thus showing the feasibility of these techniques for gauge theory problems.