Tue·Aug 31, 2021Tuesday·August 31, 2021

1. 01*

   High order quark number susceptibilities in hot QCD from lattice EQCD

   Kari Rummukainen🇫🇮 · Niels Schlusser🇫🇮

   Building on the experience of [1], we develop a formalism to construct operators for higher derivatives of the pressure in hot QCD with respect to the quark chemical potential $\mu$. We provide formulae for the operators up to the sixth derivative, and obtain continuum-extrapolated results from lattice EQCD at zero and finite $\mu$ and at six different pairs of temperature T and number of massless quark flavors $n_f$. Our data is benchmarked against full-QCD lattice and perturbative results, allowing to judge the quality of the perturbative series expansion in EQCD and the dimensional reduction procedure as a whole.

   hep-lathep-phPRD(2022)·1 citation
2. 02*

   Path integrals, complex probabilities and the discrete Weyl representation

   Wayne Polyzou🇺🇸

   A discrete formulation of the real-time path integral as the expectation value of a functional of paths with respect to a complex probability on a sample space of discrete valued paths is explored. The formulation in terms of complex probabilities is motivated by a recent reinterpretation of the real-time path integral as the expectation value of a potential functional with respect to a complex probability distribution on cylinder sets of paths. The discrete formulation in this work is based on a discrete version of Weyl algebra that can be applied to any observable with a finite number of outcomes. The origin of the complex probability in this work is the completeness relation. In the discrete formulation the complex probability exactly factors into products of conditional probabilities and exact unitarity is maintained at each level of approximation. The approximation of infinite dimensional quantum systems by discrete systems is discussed. Applications to scattering theory and quantum field theory are illustrated.

   ↳ quant-phhep-lathep-thnucl-thJ.Phys.A(2024)·6 citations
3. 03*

   Inverse magneto-rotational catalysis and the phase diagram of a rotating hot and magnetized quark matter

   N. Sadooghi🇮🇷 · S. M. A. Tabatabaee🇮🇷 · F. Taghinavaz🇮🇷

   We study the properties of a hot and magnetized quark matter in a rotating cylinder in the presence of a constant magnetic field. To do this, we solve the corresponding Dirac equation using the Ritus eigenfunction method. This leads to the energy dispersion relation, Ritus eigenfunctions, and the quantization relation for magnetized fermions. To avoid causality-violating effects, we impose a certain global boundary condition, and study its effect, in particular, on the energy eigenmodes and the quantization relations of fermions. Using the fermion propagator arising from this method, we then solve the gap equation at zero and nonzero temperatures. At zero temperature, the dynamical mass $\bar{m}$ does not depend on the angular frequency, as expected. We thus study its dependence on the distance $r$ relative to the axis of rotation and the magnetic field $B$, and explore the corresponding finite size effect for various couplings $G$. We then consider the finite temperature case. The dependence of $\bar{m}$ on the temperature $T$, magnetic field $B$, angular frequency $\Omega$, and distance $r$ for various $G$ is studied. We show that $\bar{m}$ decreases, in general, with $B$ and $\Omega$. This is the ''inverse magneto-rotational catalysis (IMRC)'' or the ''rotational magnetic inhibition'', previously discussed in the literature. To explore the evidence of this effect in the phase diagrams of our model, we examine the phase portraits of the critical temperature $T_c$ as well as the critical angular frequency ${\Omega }_c$ with respect to $G,B,\Omega$, and $r$ as well as $G,B,T$, and $r$, respectively. We show that $T_c$ and ${\Omega }_c$ decrease, in particular, with $B$. This is interpreted as clear evidence for IMRC.

   ↳ hep-phhep-latnucl-thPRD(2021)·47 citations
4. 04*

   Di-Gluonium Sum Rules, I = 0 Scalar Mesons and Conformal Anomaly

   Stephan Narison · LUPM (CNRS Montpellier-FR) · iHEPMAD (Univ. Antananarivo-MG)

   We revisit, scrutinize, improve, confirm and complete our previous results [1-3] from the scalar di-gluonium sum rules within the standard SVZ-expansion at N2LO without instantons and beyond the minimal duality ansatz : "one resonance + QCD continuum" parametrization of the spectral function which is necessary for a better understanding of the complex spectra of the $I=0$ scalar mesons. We select different (un)subtracted sum rules (USR) moments of degree $\le$ 4 for extracting the two lowest gluonia masses and couplings. We obtain: $[M_{{\sigma }_B},f_{{\sigma }_B}]=[1.07(13),0.46(16)],[M_{G_1},f_{G_1}][1.55(12),0.37(11)]$ GeV and the corresponding masses of the radial excitations : $M_{{\sigma }_B^{\prime }}$= 1.11(12) and $M_{G_1^{\prime }}=1.56(14)$ GeV which are (unexpectedly) almost degenerated with the ground states. The 2nd radial excitation is found to have a much heavier mass: $M_{G_2}\simeq$ 2.99(22) GeV. Combining these results with some Low-Energy Vertex Sum Rules (LEV-SR), we predict some hadronic widths and classify them into two groups : -- The $\sigma$-like (${\sigma }_B,{\sigma }_B^{\prime }$) which decay copiously to $\pi \pi$ from OZI-violating process and the ${\sigma }_B^{\prime }$ to $2(\pi \pi )S$ through $\sigma \sigma$. -- The $G$-like $(G_1,G_1^{\prime }$ and eventually $G_2$) which decay into ${\eta }^{\prime }\eta ,\eta \eta$ through the $U(1{)}_A$ gluonic vertex. Besides some eventual mixings with quarkonia states, we may expect that the observed $\sigma /f_0(500)$ and $f_0(137)$ are $\sigma$-like while the $f_0(1.5)$ and $f_0(1.7)$ are $G$-like gluonia. The high mass $G_2(2.99)$ can also mix with the $G_1,G_1^{\prime }$ to bring the gluon component of the gluonia candidates above 2 GeV. We also estimate the conformal charge ${\psi }_G(0)=2.09(29)$ GeV${}^4$ and its slope $10^2{\psi }_G^{\prime }(0)=-22(29)$ GeV${}^2$. Our results are summarized in Table 1.

   ↳ hep-phhep-exhep-latNPA(2022)·17 citations
5. 05*

   Primitive Quantum Gates for Dihedral Gauge Theories

   M. Sohaib Alam🇺🇸 · Stuart Hadfield🇺🇸 · Henry Lamm🇺🇸 · Andy C. Y. Li🇺🇸

   We describe the simulation of dihedral gauge theories on digital quantum computers. The nonabelian discrete gauge group $D_N$ -- the dihedral group -- serves as an approximation to $U(1)\times {\mathbb{Z}}_2$ lattice gauge theory. In order to carry out such a lattice simulation, we detail the construction of efficient quantum circuits to realize basic primitives including the nonabelian Fourier transform over $D_N$, the trace operation, and the group multiplication and inversion operations. For each case the required quantum resources scale linearly or as low-degree polynomials in $n=\log N$. We experimentally benchmark our gates on the Rigetti Aspen-9 quantum processor for the case of $D_4$. The fidelity of all $D_4$ gates was found to exceed $80\%$.

   ↳ quant-phhep-lathep-phPRD(2022)·71 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.