Thu·Nov 17, 2022Thursday·November 17, 2022

1. 01*

   Phase structure and critical point in heavy-quark QCD at finite temperature

   Kazuyuki Kanaya🇯🇵 · Ryo Ashikawa🇯🇵 · Shinji Ejiri🇯🇵 · Masakiyo Kitazawa🇯🇵 · Hiroshi Suzuki🇯🇵 · Naoki Wakabayashi🇯🇵

   We study phase structure and critical point of finite-temperature QCD in the heavy-quark region applying the hopping parameter expansion (HPE). We first study finite-size scaling on the critical point on $N_t=4$ lattices with large spatial volumes taking the leading order (LO) and the next-to-leading order (NLO) effects of the HPE, and find that the critical scaling of the Z(2) universality class expected around the critical point of two-flavor QCD is realized when the aspect ratio of the lattice is larger than about 9. This enables us to determine the critical point in the thermodynamic limit with high precisions. By a study of the convergence of the HPE, we confirm that the result of the critical point with the LO (NLO) approximation of the HPE is fairly accurate for $N_t=4$ (6), while we need to incorporate higher order effects for larger $N_t$. To extend the study to large $N_t$ lattices, we then develop a method to take the effects of higher-order terms of the HPE up to a sufficiently high order. We report on the status of our study on $N_t=6$ lattice adopting the new method.

   hep-latPoS(2023)·2 citations
2. 02*

   RG-running of the tensor currents for $N_f$ =3 QCD in a $\chi SF$ setup

   Isabel Campos Plasencia🇪🇸 · Mattia Dalla Brida🇨🇭 · Giulia Maria de Divitiis🇮🇹 · Andrew Lytle🇺🇸 · Mauro Papinutto🇮🇹 · Ludovica Pirelli🇮🇹 · Anastassios Vladikas🇮🇹

   We present the preliminary results of the non-perturbative running of the flavour non-singlet tensor operator in the high-energy range $2\mathrm{GeV}\lesssim \mu \lesssim 128\mathrm{GeV}$ in $N_f=3$ massless QCD, comparing four different definitions of the renormalisation constant. We use the configuration ensembles of arXiv:1802.05243 and arXiv:1607.06423, subject to Schrödinger functional (SF) boundary conditions, and valence quarks with chirally rotated Schrödinger functional ($\chi$SF) boundary conditions. Provided that boundary counterterms have been appropriately tuned, this results in O($a$) improvement of the tensor operator, without the need of a dimension-4 Symanzik counterterm (proportional to $c_T$).

   hep-latPoS(2023)·0 citations
3. 03*

   Semidefinite Programs at Finite Fermion Density

   Scott Lawrence🇺🇸

   Semidefinite programs can be constructed to provide a non-perturbative view of the zero-temperature behavior of quantum systems. This paper examines the properties of these semidefinite programs when applied to lattice-regulated field theories exhibiting fermion sign problems. Specifically on the finite-density Thirring model, there is no indication that the accuracy of semidefinite programs suffers from any difficulty analogous to the sign problem.

   hep-latPRD(2023)·17 citations
4. 04*

   Cellular automaton for spinor gravity in four dimensions

   C. Wetterich🇩🇪

   Certain fermionic quantum field theories are equivalent to probabilistic cellular automata, with fermionic occupation numbers associated to bits. We construct an automaton that represents a discrete model of spinor gravity in four dimensions. Local Lorentz symmetry is exact on the discrete level and diffeomorphism symmetry emerges in the naive continuum limit. Our setting could serve as a model for quantum gravity if diffeomorphism symmetry is realized in the true continuum limit and suitable collective fields for vierbein and metric acquire nonvanishing expectation values. The discussion of this interesting specific model reveals may key qualitative features of the continuum limit for probabilistic cellular automata. This limit obtains for a very large number of cells if the probabilistic information is sufficiently smooth. It is associated to coarse graining. The automaton property that every bit configuration is updated at every discrete time step to precisely one new bit configuration does no longer hold on the coarse grained level. A coarse grained configuration of occupation numbers can evolve into many different configurations with certain probabilities. This characteristic feature of quantum field theories can come along with the emergence of continuous space-time symmetries.

   hep-latgr-qcquant-phJ.Phys.Conf.Ser.(2023)·6 citations
5. 05*

   Gravitational Waves from dark composite dynamics

   Manuel Reichert🇬🇧 · Zhi-Wei Wang🇨🇳

   We discuss the stochastic gravitational-wave spectrum from dark confinement and chiral phase transitions in the early Universe. Specifically, we look at pure Yang-Mills theory for an arbitrary number of colours as well as SU(3) with quarks in different representations. We utilise thermodynamic lattice data and map it to effective models, such as the Polyakov-loop and the PNJL model. This allows us to compute gravitational-wave parameters and the corresponding gravitational-wave signal. We compare the signal to future gravitational-wave observatories such as the Big Bang Observer and DECIGO.

   ↳ hep-phastro-ph.COhep-lathep-thEPJ Web Conf.(2022)·26 citations
6. 06*

   Ground state baryons in the flux-tube three-body confinement model using Diffusion Monte Carlo

   Yao Ma🇨🇳 · Lu Meng🇩🇪 · Yan-Ke Chen🇨🇳 · Shi-Lin Zhu🇨🇳

   We make a systematical diffusion Monte Carlo (DMC) calculation for all ground state baryons in two confinement scenarios, the pairwise confinement and the three-body flux-tube confinement. With the baryons as an example, we illustrate a feasible procedure to investigate the few-quark states with possible few-body confinement mechanisms, which can be extended to the multiquark states easily. For each baryon, we extract the mass, mean-square radius, charge radius, and the quark distributions. We use the Jackknife resampling method to estimate the statistical uncertainties of masses to be less than 1 MeV. To determine the baryon charge radii, we include the constituent quark size effect, which is fixed by the experimental and lattice QCD results. Our results show that both two-body and three-body confinement mechanisms can give a good description of the experimental data if the parameters are chosen properly. In the flux-tube confinement, introducing different tension parameters for the baryons and mesons are necessary, specifically, ${\sigma }_Y=0.9204{\sigma }_{Q\bar{Q}}$. The lesson from the calculation of the nucleon mass with the DMC method is that the improper pre-assignment of the channels may prevent us from obtaining the real ground state. With this experience, we obtain the real ground state (the ${\eta }_c{\eta }_c$ threshold with the di-meson configuration) of the $cc\bar{c}\bar{c}$ system with $J^{PC}=0^{++}$ starting from the diquark-antidiquark spin-color channels alone, which is hard to achieve in the variational method and was not obtained in the previous DMC calculations.

   ↳ hep-phhep-exhep-latnucl-thPRD(2023)·25 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.