An efficient method to compute the residual phase on a Lefschetz thimble

We propose an efficient method to compute the so-called residual phase that appears when performing Monte Carlo calculations on a Lefschetz thimble. The method is stochastic and its cost scales linearly with the physical volume, linearly with the number of stochastic estimators and quadratically with the length of the extra dimension along the gradient flow. This is a drastic improvement over previous estimates of the cost of computing the residual phase. We also report on basic tests of correctness and scaling of the code.Comment: New simulations, new plot, new appendix added. To appear in PRD. 9 pages, 3 figure

Light Hadron Spectrum in the Instanton Liquid Model

We review our recent study of the role played by the chiral interactions induced by instantons, in the lowest-lying sector of the light hadron spectrum. We discuss how the ordering of the lowest meson and baryon excitations is explained by the structure of the instanton-induced quark-quark and gluon-gluon interaction. We focus on the pion, nucleon, vector- and axial-vector mesons, and on the scalar glueball. We find that all these hadrons are bound in this model and have realistic masses.Comment: 8 pages, talk given at "Hadron 07", XII International Conference on Hadron Spectroscopy, Frascati, October 8-13, 200

Exploring the Chiral Regime of QCD in the Interacting Instanton Liquid Model

Since contemporary lattice QCD calculations have highlighted the need to understand the dependence of QCD observables on the quark mass, this paper presents the framework to investigate this dependence in the context of the Interacting Instanton Liquid Model (IILM). By computing the nucleon and pion masses for a wide range of quark masses, we show that the IILM reproduces the existing lattice data for pion masses in the range 450 - 730 MeV. We also show that in the low-pion mass regime, the nucleon mass dependence in this model is consistent with O(p^4) Chiral Perturbation Theory and O(p^3) Baryon Chiral Perturbation theory. The nucleon sigma-term extracted from this analysis is in qualitative agreement with but slightly below the result from recent lattice calculations. To further explore this model in the chiral regime, we show that the spectral density of the Dirac operator and the three-point scalar correlation function agree with the behavior expected from chiral perturbation theory for two flavors. In the IILM, we identify a characteristic quark energy scale, m*= 80 MeV, which governs the zero mode zone and thus the scale for instanton mediated chiral symmetry breaking, and discuss its physical significance

Composting strategy for developing cities: A case study of Beira, Mozambique

This article aims to provide a contribution to the value and possibility of using composting as a tool for the treatment and management of the organic fraction of urban solid waste in developing contexts \u2013 specifically, the city of Beira, Mozambique. The aforementioned process should be intended not as an exhaustive tool but rather as a useful form of treatment to be employed within an Integrated Waste Management Plan. The high and diversified presence of materials suitable for the specific treatment in question is ascertained while also highlighting the diversification of the users that can be involved. Mixing strategies are drawn up in order to provide indications for a correct composition of the matrix that is intended to be started as a process and, according to the quantities considered (according to a modular approach), the production that can derive from it. A technical proposal is then drawn up on the functional areas making up the plant in order to develop the process in question. In addition to promoting the composting process itself, the article aims to valorize its final product, the compost, which in certain specific contexts, such as the one considered, can be useful or even necessary

Spectra of Free Diquark in the Bethe-Salpeter Approach

In this work, we employ the Bethe-Salpeter (B-S) equation to investigate the spectra of free diquarks and their B-S wave functions. We find that the B-S approach can be consistently applied to study the diqaurks with two heavy quarks or one heavy and one light quarks, but for two light-quark systems, the results are not reliable. There are a few free parameters in the whole scenario which can only be fixed phenomenologically. Thus, to determine them, one has to study baryons which are composed of quarks and diquarks.Comment: 16 pages, no figure

Study of shock waves generation, hot electron production and role of parametric instabilities in an intensity regime relevant for the shock ignition

We present experimental results at intensities relevant to Shock Ignition obtained at the sub-ns Prague Asterix Laser System in 2012 . We studied shock waves produced by laser-matter interaction in presence of a pre-plasma. We used a first beam at 1ω (1315 nm) at 7 × 10 13 W/cm 2 to create a pre-plasma on the front side of the target and a second at 3ω (438 nm) at ∼ 10 16 W/cm 2 to create the shock wave. Multilayer targets composed of 25 (or 40 μm) of plastic (doped with Cl), 5 μm of Cu (for Kα diagnostics) and 20 μm of Al for shock measurement were used. We used X-ray spectroscopy of Cl to evaluate the plasma temperature, Kα imaging and spectroscopy to evaluate spatial and spectral properties of the fast electrons and a streak camera for shock breakout measurements. Parametric instabilities (Stimulated Raman Scattering, Stimulated Brillouin Scattering and Two Plasmon Decay) were studied by collecting the back scattered light and analysing its spectrum. Back scattered energy was measured with calorimeters. To evaluate the maximum pressure reached in our experiment we performed hydro simulations with CHIC and DUED codes. The maximum shock pressure generated in our experiment at the front side of the target during laser-interaction is 90 Mbar. The conversion efficiency into hot electrons was estimated to be of the order of ∼ 0.1% and their mean energy in the order ∼50 keV. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distributio

Composting Strategy for Developing Cities: A Case Study of Beira, Mozambique

This article aims to provide a contribution to the value and possibility of using composting as a tool for the treatment and management of the organic fraction of urban solid waste in developing contexts – specifically, the city of Beira, Mozambique. The aforementioned process should be intended not as an exhaustive tool but rather as a useful form of treatment to be employed within an Integrated Waste Management Plan. The high and diversified presence of materials suitable for the specific treatment in question is ascertained while also highlighting the diversification of the users that can be involved. Mixing strategies are drawn up in order to provide indications for a correct composition of the matrix that is intended to be started as a process and, according to the quantities considered (according to a modular approach), the production that can derive from it. A technical proposal is then drawn up on the functional areas making up the plant in order to develop the process in question. In addition to promoting the composting process itself, the article aims to valorize its final product, the compost, which in certain specific contexts, such as the one considered, can be useful or even necessary. © 2020 WIT Press

Anomaly and a QCD-like phase diagram with massive bosonic baryons

We study a strongly coupled $Z_2$ lattice gauge theory with two flavors of quarks, invariant under an exact $\mathrm{SU}(2)\times \mathrm{SU}(2) \times \mathrm{U}_A(1) \times \mathrm{U}_B(1)$ symmetry which is the same as QCD with two flavors of quarks without an anomaly. The model also contains a coupling that can be used to break the $\mathrm{U}_A(1)$ symmetry and thus mimic the QCD anomaly. At low temperatures $T$ and small baryon chemical potential $\mu_B$ the model contains massless pions and massive bosonic baryons similar to QCD with an even number of colors. In this work we study the $T-\mu_B$ phase diagram of the model and show that it contains three phases : (1) A chirally broken phase at low $T$ and $\mu_B$, (2) a chirally symmetric baryon superfluid phase at low $T$ and high $\mu_B$, and (3) a symmetric phase at high $T$. We find that the nature of the finite temperature chiral phase transition and in particular the location of the tricritical point that seperates the first order line from the second order line is affected significantly by the anomaly.Comment: 22 pages, 16 figures, 5 tables, references adde