Wed·Oct 20, 2021Wednesday·October 20, 2021

1. 01*

   Localization properties of Dirac modes at the Roberge-Weiss phase transition

   Marco Cardinali🇮🇹 · Massimo D'Elia🇮🇹 · Francesco Garosi🇮🇹 · Matteo Giordano🇭🇺

   We study the localization properties of the low-lying Dirac eigenmodes in QCD at imaginary chemical potential ${\hat{\mu }}_I=\pi$ at temperatures above the Roberge-Weiss transition temperature $T_{\mathrm{RW}}$. We find that modes are localized up to a temperature-dependent "mobility edge" and delocalized above it, and that the mobility edge extrapolates to zero at a temperature compatible with $T_{\mathrm{RW}}$. This supports the existence of a strong connection between localization of the low Dirac modes and deconfinement, studied here for the first time in a model with a genuine deconfinement transition in the continuum limit in the presence of dynamical fermions.

   hep-lathep-phhep-thPRD(2022)·18 citations
2. 02*

   Extraction of $B_s\to D_s^{(\ast )}$ form factors from $N_f=2$ lattice QCD

   Benoît Blossier🇫🇷 · Pierre-Henri Cahue🇫🇷 · Jochen Heitger🇩🇪 · Simone LaCesa · Jan Neuendorf🇫🇷 · Savvas Zafeiropoulos🇫🇷

   We report on a two-flavour lattice QCD study of the $B_s\to D_s$ and $B_s\to D_s^{\ast }$ transitions parameterized, in the heavy quark limit, by the form factors $\mathcal{G}$, and $h_{A_1}$, $h_{A_2}$ and $h_{A_3}$, respectively. In the search for New Physics through tests of lepton flavour universality, $B_s$ decay channels are complementary to the $B$ decays widely studied at $B$ factories and LHCb, while on the theory side they can be better controlled than the $B_c$ and ${\Lambda }_b$ decays. The purpose of this exploratory two-flavour study is, in preparation for future analyses of lattice QCD simulations with $N_f>2$ and physical quark-masses, to gain experience on a suitable method for a lattice extraction of form factors associated with $b\to c$ currents that may yield tighter control over systematic effects like contamination from excited states and cut-off effects. We obtain the zero-recoil values ${\mathcal{G}}^{B_s\to D_s}(1)=1.03(14)$ and $h^{B_s\to D_s^{\ast }}(1)=0.85(16)$.

   hep-latPRD(2022)·8 citations
3. 03*

   One-loop unquenched three-gluon and ghost-gluon vertex in the Curci-Ferrari model

   Felipe Figueroa🇫🇷 · Marcela Peláez🇺🇾

   In this article we study the unquenched three-gluon and ghost-gluon vertex in all momentum range going from the ultraviolet to the infrared regime using the Curci-Ferrari model at one-loop in Landau gauge as an extension of the results presented in \cite{Pelaez:2013cpa}. Results are compared with recent lattice data for $SU(3)$ in the unquenched case. This calculation is a pure prediction of the model because it does not require fixing any parameter once two-point functions are fitted. An analysis of the influence of dynamical quarks in the position of the zero crossing of the three-gluon vertex is presented. Due to the recent improvements in infrared lattice data for the quenched three-gluon correlation function \cite{Aguilar:2021lke} we also redo the comparison between our one-loop results in this limit and the lattice obtaining a very good match.

   ↳ hep-thhep-lathep-phPRD(2022)·15 citations
4. 04*

   Effects of Cosine Tapering Window on Quantum Phase Estimation

   Gumaro Rendon🇺🇸 · Taku Izubuchi🇺🇸 · Yuta Kikuchi🇺🇸

   We provide a modification to the quantum phase estimation algorithm (QPEA) inspired on classical windowing methods for spectral density estimation. From this modification we obtain an upper bound in the cost that implies a cubic improvement with respect to the algorithm's error rate. Numerical evaluation of the costs also demonstrates an improvement. Moreover, with similar techniques, we detail an iterative projective measurement method for ground state preparation that gives an exponential improvement over previous bounds using QPEA. Numerical tests that confirm the expected scaling behavior are also obtained. For these numerical tests we have used a Lattice Thirring model as testing ground. Using well-known perturbation theory results, we also show how to more appropriately estimate the cost scaling with respect to state error instead of evolution operator error.

   ↳ quant-phhep-latPRD(2022)·24 citations
5. 05*

   Confinement and Flux Attachment

   Djordje Radicevic🇺🇸

   Flux-attached theories are a novel class of lattice gauge theories whose gauge constraints involve both electric and magnetic operators. Like ordinary gauge theories, they possess confining phases. Unlike ordinary gauge theories, their confinement does not imply a trivial gapped vacuum. This paper will offer three lessons about the confining phases of flux-attached ${\mathbb{Z}}_K$ theories in two spatial dimensions. First, on an arbitrary orientable lattice, flux attachment that satisfies a simple, explicitly derived criterion leads to a confining theory whose low-energy behavior is captured by an action of a general Chern-Simons form. Second, on a square lattice, this criterion can be solved, and all theories that satisfy it can be enumerated. The simplest such theory has an action given by a difference of two Chern-Simons terms, and it features a kind of subsystem symmetry that causes its topological entanglement entropy to behave pathologically. Third, the simplest flux-attached theory on a square lattice that does not satisfy the above criterion is exactly solvable when the gauge group is ${\mathbb{Z}}_2$. On a torus, its confined phase possesses a twofold topological degeneracy that stems from a sum over spin structures in a dual fermionic theory. This makes this flux-attached ${\mathbb{Z}}_2$ theory an appealing candidate for a microscopic description of a $\mathrm{U}(1{)}_2$ Chern-Simons theory.

   ↳ hep-thcond-mat.stat-mechcond-mat.str-elhep-lat+24 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.