Tue·Sep 14, 2021Tuesday·September 14, 2021

1. 01*

   Inhomogeneities in the $2$-Flavor Chiral Gross-Neveu Model

   Julian J. Lenz🇩🇪 · Michael Mandl🇩🇪 · Andreas Wipf🇩🇪

   We investigate the finite-temperature and -density chiral Gross-Neveu model with an axial U${}_A$(1) symmetry in $1+1$ dimensions on the lattice. In the limit where the number of flavors $N_{\mathrm{f}}$ tends to infinity the continuum model has been solved analytically and shows two phases: a symmetric high-temperature phase with a vanishing condensate and a low-temperature phase in which the complex condensate forms a chiral spiral which breaks translation invariance. In the lattice simulations we employ chiral SLAC fermions with exact axial symmetry. Similarly to $N_{\mathrm{f}}\to \infty$, we find for $8$ flavors, where quantum and thermal fluctuations are suppressed, two distinct regimes in the $(T,\mu )$ phase diagram, characterized by qualitatively different behavior of the two-point functions of the condensate fields. More surprisingly, at $N_{\mathrm{f}}=2$, where fluctuations are no longer suppressed, the model still behaves similarly to the $N_{\mathrm{f}}\to \infty$ model and we conclude that the chiral spiral leaves its footprints even on systems with a small number of flavors. For example, at low temperature the two-point functions are still dominated by chiral spirals with pitches proportional to the inverse chemical potential, although in contrast to large-$N_{\mathrm{f}}$ their amplitudes decrease with distance. We argue that these results should not be interpreted as the spontaneous breaking of a continuous symmetry, which is forbidden in two dimensions. Finally, using Dyson-Schwinger equations we calculate the decay of the U${}_A$(1)-invariant fermion four-point function in search for a BKT phase at zero temperature.

   hep-latcond-mat.str-elhep-thPRD(2022)·33 citations
2. 02*

   Non-invertible topological defects in 4-dimensional ${\mathbb{Z}}_2$ pure lattice gauge theory

   Masataka Koide🇯🇵 · Yuta Nagoya🇯🇵 · Satoshi Yamaguchi🇯🇵

   We explore topological defects in the 4-dimensional pure ${\mathbb{Z}}_2$ lattice gauge theory. This theory has 1-form ${\mathbb{Z}}_2$ center symmetry as well as the Kramers-Wannier-Wegner (KWW) duality. We construct the KWW duality topological defects in the similar way to that constructed by Aasen, Mong, Fendley arXiv:1601.07185 for the 2-dimensional Ising model. These duality defects turn out to be non-invertible. We also construct the 1-form ${\mathbb{Z}}_2$ symmetry defects as well as the junctions among KWW duality defects and 1-form ${\mathbb{Z}}_2$ center symmetry defects. The crossing relations among these defects are derived. The expectation values of some configurations of these topological defects are calculated by using these crossing relations.

   ↳ hep-thcond-mat.stat-mechhep-latPTEP(2022)·123 citations
3. 03*

   Quantum Criticality of Anti-ferromagnetism and Superconductivity with Relativity

   Hanqing Liu🇺🇸 · Emilie Huffman🇨🇦 · Shailesh Chandrasekharan🇺🇸 · Ribhu K. Kaul🇺🇸

   We study a quantum phase transition from a massless to massive Dirac fermion phase in a new two-dimensional bipartite lattice model of electrons that is amenable to sign-free quantum Monte Carlo simulations. Importantly, interactions in our model are not only invariant under $\text{SU}(2)$ symmetries of spin and charge like the Hubbard model, but they also preserve an Ising like electron spin-charge flip symmetry. From unbiased fermion bag Monte Carlo simulations with up to 2304 sites, we show that the massive fermion phase spontaneously breaks this Ising symmetry, picking either anti-ferromagnetism or superconductivity and that the transition at which both orders are simultaneously quantum critical, belongs to a new "chiral spin-charge symmetric" universality class. We explain our observations using effective potential and renormalization group calculations within the framework of a continuum field theory.

   ↳ cond-mat.str-elhep-latPRL(2022)·12 citations
4. 04*

   Fine corrections in the effective string describing SU(2) Yang-Mills theory in three dimensions

   Fabrizio Caristo🇮🇹 · Michele Caselle🇮🇹 · Nicodemo Magnoli🇮🇹 · Alessandro Nada🇮🇹 · Marco Panero🇮🇹 · Antonio Smecca🇮🇹

   We present a study of the effective string that describes the infrared dynamics of SU(2) Yang-Mills theory in three dimensions. By combining high-precision lattice simulation results for Polyakov-loop correlators at finite temperatures close to (and less than) the deconfinement one with the analytical constraints from renormalization-group arguments, from the exact integrability of the two-dimensional Ising model that describes the universality class of the critical point of the theory, from conformal perturbation theory, and from Lorentz invariance, we derive tight quantitative bounds on the corrections to the effective string action beyond the Nambu-Goto approximation. We show that these corrections are compatible with the predictions derived from a bootstrap analysis of the effective string theory, and have a value which does not allow to prove the Axionic String Ansatz for this model

   ↳ hep-thhep-latJHEP(2022)·23 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.