Structure Factors of Neutron Matter at Finite Temperature.

We compute continuum and infinite volume limit extrapolations of the structure factors of neutron matter at finite temperature and density. Using a lattice formulation of leading-order pionless effective field theory, we compute the momentum dependence of the structure factors at finite temperature and at densities beyond the reach of the virial expansion. The Tan contact parameter is computed and the result agrees with the high momentum tail of the vector structure factor.

Fermions at Finite Density in 2+1 Dimensions with Sign-Optimized Manifolds.

We present Monte Carlo calculations of the thermodynamics of the (2+1)-dimensional Thirring model at finite density. We bypass the sign problem by deforming the domain of integration of the path integral into complex space in such a way as to maximize the average sign within a parameterized family of manifolds. We present results for lattice sizes up to 10^{3} and we find that at high densities and/or temperatures the chiral condensate is abruptly reduced.

Monte Carlo Study of Real Time Dynamics on the Lattice.

Monte Carlo studies involving real time dynamics are severely restricted by the sign problem that emerges from a highly oscillatory phase of the path integral. In this Letter, we present a new method to compute real time quantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo simulations. The key idea is to deform the path integration domain to a complex manifold where the phase oscillations are mild and the sign problem is manageable.