A Novel Quark-field Creation Operator Construction for Hadronic Physics in Lattice QCD.

A Novel Quark-field Creation Operator Construction for Hadronic Physics in Lattice QCD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
A new quark-field smearing algorithm is defined which enables efficient calculations of a broad range of hadron correlation functions. The technique applies a low-rank operator to define smooth fields, that are to be used in hadron creation operators. The resulting space of smooth fields is small enough that all elements of the reduced quark propagator can be computed exactly at reasonable computational cost. Correlations between arbitrary sources, including multi-hadron operators can be computed {\em a posteriori} without requiring new lattice Dirac operator inversions. The method is tested on realistic lattice sizes with light dynamical quarks.

A Novel Quark-field Creation Operator Construction for Hadronic Physics in Lattice QCD.

A Novel Quark-field Creation Operator Construction for Hadronic Physics in Lattice QCD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
A new quark-field smearing algorithm is defined which enables efficient calculations of a broad range of hadron correlation functions. The technique applies a low-rank operator to define smooth fields, that are to be used in hadron creation operators. The resulting space of smooth fields is small enough that all elements of the reduced quark propagator can be computed exactly at reasonable computational cost. Correlations between arbitrary sources, including multi-hadron operators can be computed {\em a posteriori} without requiring new lattice Dirac operator inversions. The method is tested on realistic lattice sizes with light dynamical quarks.

Structure of Nucleon Excited States from Lattice QCD

Structure of Nucleon Excited States from Lattice QCD PDF Author: Finn M. Stokes
Publisher: Springer Nature
ISBN: 3030257223
Category : Science
Languages : en
Pages : 237

Get Book Here

Book Description
Quantum Chromodynamics (QCD) describes the interactions between elementary quarks and gluons as they compose the nucleons at the heart of atomic structure. The interactions give rise to complexity that can only be examined via numerical simulations on supercomputers. This work provides an introduction to the numerical simulations of lattice QCD and establishes new formalisms relevant to understanding the structure of nucleons and their excited states. The research opens with an examination of the non-trivial QCD vacuum and the emergence of “centre domains.” The focus then turns to establishing a novel Parity-Expanded Variational Analysis (PEVA) technique solving the important problem of isolating baryon states moving with finite momentum. This seminal work provides a foundation for future calculations of baryon properties. Implementation of the PEVA formalism discloses important systematic errors in conventional calculations and reveals the structure of nucleon excited states from the first principles of QCD for the first time.

Hadronic Physics from Lattice QCD

Hadronic Physics from Lattice QCD PDF Author: Anthony M. Green
Publisher: World Scientific
ISBN: 9812701389
Category : Science
Languages : en
Pages : 385

Get Book Here

Book Description
Particle and nuclear physicists frequently take results from Lattice QCD at their face value without probing into their reliability or sophistication. This attitude usually stems from a lack of knowledge of the field. The aim of the present volume is to rectify this by introducing in an elementary way several topics, which we believe are appropriate for, and of possible interest to, both particle and nuclear physicists who are non-experts in the field.

Exascale Scientific Applications

Exascale Scientific Applications PDF Author: Tjerk P. Straatsma
Publisher: CRC Press
ISBN: 1351999249
Category : Computers
Languages : en
Pages : 607

Get Book Here

Book Description
Describes practical programming approaches for scientific applications on exascale computer systems Presents strategies to make applications performance portable Provides specific solutions employed in current application porting and development Illustrates domain science software development strategies based on projected trends in supercomputing technology and architectures Includes contributions from leading experts involved in the development and porting of scientific codes for current and future high performance computing resources

Hadron Spectroscopy And Structure - Proceedings Of The Xviii International Conference

Hadron Spectroscopy And Structure - Proceedings Of The Xviii International Conference PDF Author: Feng-kun Guo
Publisher: World Scientific
ISBN: 981121932X
Category : Science
Languages : en
Pages : 800

Get Book Here

Book Description
This is the conference proceedings for the 18th International Conference on Hadron Spectroscopy and Structure (HADRON2019), held in Guilin, China. It is among the most important conference series in the field of hadron spectroscopy and structure. Collecting more than 130 contributions from this conference, the book spans over the topics of meson and baryon spectroscopy, exotic hadrons, hadron production and interactions, analysis tools, QCD and hadron structure, hadrons in nuclear environment and hypernuclei. Summaries of the recent discoveries from Belle, BESIII, LHCb and other high-energy experiments, as well as recent theoretical developments in the above mentioned topics, are contained in this volume, rendering it as a valuable resource for researchers working on hadron spectroscopy and structure.

Quark Confinement And The Hadron Spectrum Iv

Quark Confinement And The Hadron Spectrum Iv PDF Author: Wolfgang Lucha
Publisher: World Scientific
ISBN: 9814491454
Category :
Languages : en
Pages : 388

Get Book Here

Book Description
Quantum chromodynamics is generally accepted to be the quantum field theory which describes the strong interactions in elementary particle physics. However, the question of the mechanism responsible for the “confinement” of the color degrees of freedom of quarks and gluons into hadrons still ranks as one of the most interesting open problems in physics.This proceedings volume summarizes the state of the art in this area of research. Mathematically inclined readers will find the articles based on monopoles, vortices, and topology most interesting. Meanwhile, lattice calculations can be performed for many important physical quantities. Their results can be used as guidelines for developing models of quark confinement. These models are indispensable for theoretical physicists performing calculations with the Bethe-Salpeter equation, Dyson-Schwinger equations, effective Hamiltonians, and potential models. The cross-fertilization of all these subfields of research becomes evident from the articles in this book. A few experimental papers are also included.

Formal Developments for Lattice QCD with Applications to Hadronic Systems

Formal Developments for Lattice QCD with Applications to Hadronic Systems PDF Author: Zohreh Davoudi
Publisher:
ISBN:
Category :
Languages : en
Pages : 245

Get Book Here

Book Description
In order to make reliable predictions with controlled uncertainties for a wide range of nuclear phenomena, a theoretical bottom-up approach, by which hadrons emerge from the underlying theory of strong interactions, quantum chromodynamics (QCD), is desired. The strongly interacting quarks and gluons at low energies are responsible for all the dynamics of nucleons and their clusters, the nuclei. The theoretical framework and the combination of analytical and numerical tools used to carry out a rigorous non-perturbative study of these systems from QCD is called lattice QCD. The result of a lattice QCD calculation corresponds to that of nature only in the limit when the volume of the spacetime is taken to infinity and the spacing between discretized points on the lattice is taken to zero. A better understanding of these discretization and volume effects, not only provides the connection to the infinite-volume continuum observables, but also leads to optimized calculations that can be performed with available computational resources. This thesis includes various formal developments in this direction, along with proposals for novel improvements, to be used in the upcoming LQCD studies of nuclear and hadronic systems. As the space(time) is discretized on a (hyper)cubic lattice in (most of) lattice QCD calculations, the lattice correlation functions are not fully rotationally invariant. This is known to lead to mixing between operators (those interpolating the states or inserting external currents) of higher dimensions with those of lower dimensions where the coefficients of latter diverge with powers of inverse lattice spacing, a, as the continuum limit is approached. This issue has long posed computational challenges in lattice spectroscopy of higher spin states, as well as in the lattice extractions of higher moments of hadron structure functions. We have shown, through analytical perturbative investigations of field theories, including QCD, on the lattice that a novel choice of operators, smeared over several lattice sites and deduced from a continuum angular momentum, has a smooth continuum limit. The scaling of the lower dimensional operators is proven to be no worse than a squared, explaining the success of recent numerical studies of excited state spectroscopy of hadrons with similar choices of operators. These results are presented in chapter 2 of this thesis. Due to Euclidean nature of lattice correlation function, the physical scattering parameters must be obtained via an analytical continuation to Minkowski spacetime. However, this continuation is practically impossible in the infinite-volume limit of lattice correlation function except at the kinematic thresholds. A formalism due to Luscher overcomes this issue by making the connection between the finite-volume spectrum of two interacting particles and their infinite-volume scattering phase shifts. We have extended the Luscher methodology, using an effective field theory approach, to the two-nucleon systems with arbitrary spin, parity and total momentum (in the limit of exact isospin symmetry) and have studied its application to the deuteron system, the lightest bound states of the nucleons, by careful analysis of the finite-volume symmetries. A proposal is presented that enables future precision lattice QCD extraction of the small D/S ratio of the deuteron that is known to be due to the action of non-central forces. By investigating another scenario, we show how significant volume improvement can be achieved in the masses of nucleons and in the binding energy of the deuteron with certain choices of boundary conditions in a lattice QCD calculation of these quantities. These results are discussed in chapters 3, 4 and 5. In order to account for electromagnetic effects in hadronic systems, lattice QCD calculations have started to include quantum electrodynamic (QED). These effects are particularly interesting in studies of mass splittings between charged and neutral members of isospin multiplets, e.g. neutral and charged pions. Due to the infinite range of QED interactions large volume effects plaque these studies. Using a non-relativistic effective theory for electromagnetic interactions of hadrons, we analytically calculate, and numerically estimate, the first few finite-volume corrections (up to 1 over L to the 4th power where L is the spatial extent of the volume) to the masses of hadrons and nuclei at leading order in the QED coupling constant, but to all orders in the short-distance strong interaction effects. These results are presented in chapter 6.

Perspectives in Lattice QCD

Perspectives in Lattice QCD PDF Author: Yoshinobu Kuramashi
Publisher: World Scientific
ISBN: 9812700005
Category : Science
Languages : en
Pages : 323

Get Book Here

Book Description
This book consists of a series of lectures to cover every facet of the modern version of lattice QCD. All the lectures are self-contained starting with the necessary background material and ending up with the latest development. Most of the lectures are given by pioneers in the field.This book may be useful as an advanced textbook for graduate students in particle physics and its modern and fascinating contents will inspire the interest of the non-experts.

Quantum Operator Design for Lattice Baryon Spectroscopy

Quantum Operator Design for Lattice Baryon Spectroscopy PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
A previously-proposed method of constructing spatially-extended gauge-invariant three-quark operators for use in Monte Carlo lattice QCD calculations is tested, and a methodology for using these operators to extract the energies of a large number of baryon states is developed. This work is part of a long-term project undertaken by the Lattice Hadron Physics Collaboration to carry out a first-principles calculation of the low-lying spectrum of QCD. The operators are assemblages of smeared and gauge-covariantly-displaced quark fields having a definite flavor structure. The importance of using smeared fields is dramatically demonstrated. It is found that quark field smearing greatly reduces the couplings to the unwanted high-lying short-wavelength modes, while gauge field smearing drastically reduces the statistical noise in the extended operators.

Requirements for High Performance Computing for Lattice QCD

Requirements for High Performance Computing for Lattice QCD PDF Author: Fred Jegerlehner
Publisher:
ISBN:
Category : Hadron spectroscopy
Languages : en
Pages : 48

Get Book Here

Book Description