On the spectrum and string tension of U(1) lattice gauge theory in 2 + 1 dimensions

Abstract

We calculate the low-lying spectra of glueballs and confining flux tubes in the U(1) lattice gauge theory in 2 + 1 dimensions. We see that up to modest lattice spacing corrections, the glueball states are consistent with being multiparticle states composed of non-interacting massive J P C = 0 −− particles. We observe that the ag 2 → 0 limit is, as expected, unconventional, and follows the well-known saddle-point analysis of Polyakov to a good approximation. The spectrum of closed (winding) flux tubes exhibits the presence of a massive world-sheet excitation whose mass is consistent with that of the bulk screening mass. These U(1) calculations are intended to complement existing lattice calculations of the properties of SU(N ≥ 2) and SO(N ≥ 3) gauge theories in D = 2 + 1.

The critical temperature of the 2D-Ising model through deep learning autoencoders

“…Finally, our future plans involve the testing of the autoencoder as a tool for the unsupervised extraction of the phase structure of physical systems with continuous symmetries. These involve quantum field theories formulated on the lattice such as the 3D φ 4 with O(2) symmetry [46] where the phase transition is of second order and belongs to the same universality class as the 2D-Ising model, the 3D U (1) gauge theory [50] for which the phase transition is of infinite order and belongs to the…”

Charm quark effects on the strong coupling extracted from the static force

“…Then we extract the leading lattice artifacts comparing our calculations to the one-loop predictions of the continuum theory [15]. Such a computation has been performed in [16,17] for clover improved Wilson fermions using unsmeared links. Here we adopt the same strategy, but we have to consider a clover improved doublet of twisted mass Wilson fermions and HYP2-smeared links.…”

“…Here we adopt the same strategy, but we have to consider a clover improved doublet of twisted mass Wilson fermions and HYP2-smeared links. We just summarize the main ideas and we refer to [16,17] for further details.…”

“…This part of the calculation has been carried out using our computer package written in Mathematica. The fermionic contribution to the static force has been calculated for a sequence of finite lattice sizes (L = [16,64]) and then extrapolated to infinite volume.…”

“…Thus, we can estimate the coefficients p i of β qq performing a global best-fit to our data at different lattice spacings through the Eqs. (16) and (17). The continuum extrapolation of α qq can be realized solving the ODE which follows from the definition of the β qq -function (Eq.…”