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In this work we present lattice calculations of the masses of P-wave mesons using Monte Carlo simulations. Our valence fermions are defined by the Wilson action. Our gauge fields are generated with both dynamical staggered fermions at a…

High Energy Physics - Lattice · Physics 2016-08-31 M. Wingate , T. DeGrand , S. Collins , U. M. Heller

The first results from the Fermilab E989 experiment have confirmed the long-standing tension between the experimental determination of the muon anomalous magnetic moment $a_\mu=(g_\mu-2)/2$ and its SM determination using the dispersive…

High Energy Physics - Lattice · Physics 2021-12-07 Leonardo Giusti , Mattia Dalla Brida , Tim Harris , Michele Pepe

We calculate mesonic two-point functions in the epsilon-regime of two-flavor QCD on the lattice with exact chiral symmetry. We use gauge configurations of size 16^3 32 at the lattice spacing a \sim 0.11 fm generated with dynamical overlap…

High Energy Physics - Lattice · Physics 2008-11-26 JLQCD Collaboration , H. Fukaya , S. Aoki , S. Hashimoto , T. Kaneko , H. Matsufuru , J. Noaki , K. Ogawa , T. Onogi , N. Yamada

We describe a way to optimize the chiral behavior of Wilson-type lattice fermion actions by studying the low energy real eigenmodes of the Dirac operator. We find a candidate action, the clover action with fat links with a tuned clover…

High Energy Physics - Lattice · Physics 2007-05-23 Thomas DeGrand , Anna Hasenfratz , Tamás G. Kovács

A compression algorithm is introduced for multi-determinant wave functions which can greatly reduce the number of determinants that need to be evaluated in quantum Monte Carlo calculations. We have devised an algorithm with three levels of…

Computational Physics · Physics 2015-06-17 Gihan L. Weerasinghe , Pablo Lopez Rios , Richard J. Needs

We introduce a Monte Carlo method, as a modification of existing cluster algorithms, which allows simulations directly on systems of infinite size, and for quantum models also at beta=infinity. All two-point functions can be obtained,…

Statistical Mechanics · Physics 2007-05-23 H. G. Evertz , W. von der Linden

We report on our on-going project to compute mesonic and baryonic two- and three-point correlation functions in simulations using Nf=2 flavours of O(a) improved Wilson quarks and the Wilson plaquette action. We present performance figures…

High Energy Physics - Lattice · Physics 2010-02-23 S. Capitani , M. Della Morte , E. Endress , A. Juttner , B. Knippschild , H. Wittig , M. Zambrana

We extend the continuous-time interaction-expansion quantum Monte Carlo method with respect to measuring observables for fermion-boson lattice models. Using generating functionals, we express expectation values involving boson operators,…

Strongly Correlated Electrons · Physics 2017-01-04 Manuel Weber , Fakher F. Assaad , Martin Hohenadler

We propose a new quantum Monte Carlo algorithm to compute fermion ground-state properties. The ground state is projected from an initial wavefunction by a branching random walk in an over-complete basis space of Slater determinants. By…

Condensed Matter · Physics 2016-08-31 Shiwei Zhang , J. Carlson , J. E. Gubernatis

We describe recent results concerning the behavior of lattice QCD with light dynamical Wilson and Staggered quarks. We show that it is possible to reach regions of parameter space with light pions $m_\pi\approx 0.2/a$ using Wilson fermions.…

High Energy Physics - Lattice · Physics 2016-08-31 Khalil Bitar , Robert G. Edwards , Urs M. Heller , A. D. Kennedy

We present an investigation of gauge invariant smearing for Wilson fermions on a $24^3 \times 48$ lattice at $\beta = 6.2$. We demonstrate a smearing algorithm that allows a substantial improvement in the determination of the baryon…

High Energy Physics - Lattice · Physics 2019-08-27 UKQCD Collaboration

We present a Quantum Monte Carlo (QMC) study, based on the Langevin equation, of a Hamiltonian describing electrons coupled to phonon degrees of freedom. The bosonic part of the action helps control the variation of the field in imaginary…

Strongly Correlated Electrons · Physics 2019-01-16 G. G. Batrouni , Richard T. Scalettar

The Wilson fermion determinant can be written as product of the determinants of two hermitian positive definite matrices. This formulation allows to simulate non-degenerate quark flavors by means of the hybrid Monte Carlo algorithm. A major…

High Energy Physics - Lattice · Physics 2011-04-15 Thomas Lippert

We present recent results of SESAM's large scale lattice simulation of QCD with two dynamical flavours of Wilson fermions. The emphasis is on future prospects in the extraction of flavour-singlet matrix elements, i.e the pi-nucleon sigma…

High Energy Physics - Phenomenology · Physics 2012-08-27 SESAM-Collaboration , : , N. Eicker , U. Glässner , S. Güsken , H. Hoeber , Th. Lippert , G. Ritzenhöfer , K. Schilling , G. Siegert , A. Spitz , P. Ueberholz , J. Viehoff

We present data for the scaling behavior of lattice QCD with two flavors of light Wilson fermions. This is done by matching $\pi$ n and $\rho$ masses at the two lattice sizes of $16^3\times32 $ and $8^3\times16$. We find that at…

High Energy Physics - Lattice · Physics 2009-10-28 K. M. Bitar , R. G. Edwards , U. M. Heller , A. D. Kennedy , P. Vranas

We develop a quantum Monte Carlo method for many fermions that allows the use of any one-particle basis. It projects out the ground state by random walks in the space of Slater determinants. An approximate approach is formulated to control…

Condensed Matter · Physics 2009-02-20 Shiwei Zhang , Henry Krakauer

We introduce methodologies for highly scalable quantum Monte Carlo simulations of electron-phonon models, and report benchmark results for the Holstein model on the square lattice. The determinant quantum Monte Carlo (DQMC) method is a…

Strongly Correlated Electrons · Physics 2022-07-18 Benjamin Cohen-Stead , Owen Bradley , Cole Miles , George Batrouni , Richard Scalettar , Kipton Barros

We present a whole series of novel methods to alleviate the sign problem of the Fermionic Shadow Wave Function in the context of Variational Monte Carlo. The effectiveness of our new techniques is demonstrated on the example of liquid 3He.…

Computational Physics · Physics 2015-04-21 Francesco Calcavecchia , Francesco Pederiva , Malvin H. Kalos , Thomas D. Kühne

Previous investigations have shown that the canonical approach to simulating QCD at finite density is promising. The algorithm we used in our earlier work employs an exact calculation of the fermionic determinant which limits the size of…

High Energy Physics - Lattice · Physics 2008-11-26 Andrei Alexandru , Anyi Li , Keh-Fei Liu

Perturbative coefficients for Wilson loops and the static quark self-energy are extracted from Monte Carlo simulations at large beta on finite volumes, where all the lattice momenta are large. The Monte Carlo results are in excellent…

High Energy Physics - Lattice · Physics 2015-06-25 G. P. Lepage , P. B. Mackenzie , N. H. Shakespeare , H. D. Trottier