Dual representation for 1+1 dimensional fermions interacting with 3+1 dimensional U(1) gauge fields

We study a system of nanowires, i.e., the theory of 1 + 1 dimensional massless fermions interacting with 3 + 1 dimensional U(1) gauge fields. When allowing for nonzero chemical potentials, this system has a complex action problem in the conventional formulation. We show that the partition sum can be mapped to a dual representation where the fermions correspond to dimers and oriented loops on two-dimensional planes embedded in 4 dimensions. The dual degrees of freedom for the gauge fields are surfaces that either are closed or bounded by the fermion loops. In terms of the dual variables the complex action problem is overcome and Monte Carlo simulations are possible for arbitrary chemical potentials.