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Related papers: Complex Langevin simulation for QCD-like models

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We study QCD at finite density and low temperature by using the complex Langevin method. We employ the gauge cooling to control the unitarity norm and introduce a deformation parameter in the Dirac operator to avoid the singular-drift…

High Energy Physics - Lattice · Physics 2018-04-18 Keitro Nagata , Jun Nishimura , Shinji Shimasaki

We study the Stephanov model, which is an RMT model for QCD at finite density, using the Complex Langevin algorithm. Naive implementation of the algorithm shows convergence towards the phase quenched or quenched theory rather than to…

High Energy Physics - Lattice · Physics 2018-04-18 Jacques Bloch , Jonas Glesaaen , Jacobus Verbaarschot , Savvas Zafeiropoulos

The chemical Langevin equation (CLE) is a popular simulation method to probe the stochastic dynamics of chemical systems. The CLE's main disadvantage is its break down in finite time due to the problem of evaluating square roots of negative…

Quantitative Methods · Quantitative Biology 2014-07-22 David Schnoerr , Guido Sanguinetti , Ramon Grima

In the case of nonabelian gauge theories with a complex weight, a controlled exploration of the complexified configuration space during a complex Langevin process requires the use of SL(N,C) gauge cooling, in order to minimize the distance…

High Energy Physics - Lattice · Physics 2014-10-20 Lorenzo Bongiovanni , Gert Aarts , Erhard Seiler , Denes Sexty , Ion-Olimpiu Stamatescu

We introduce a projected complex Langevin (CL) numerical sampling method -- a fictitious Langevin dynamics scheme that uses numerical projection to sample a constrained stationary distribution with highly oscillatory character. Despite the…

Quantum Gases · Physics 2025-03-04 Ethan C. McGarrigle , Hector D. Ceniceros , Glenn H. Fredrickson

The complex Langevin (CL) method is a classical numerical strategy to alleviate the numerical sign problem in the computation of lattice field theories. Mathematically, it is a simple numerical tool to compute a wide class of…

Numerical Analysis · Mathematics 2020-11-06 Zhenning Cai , Xiaoyu Dong , Yang Kuang

We study the mechanism of the gauge cooling technique to stabilize the complex Langevin method in the one-dimensional periodic setting. In this case, we find the exact solutions for the gauge transform which minimizes the Frobenius norm of…

Numerical Analysis · Mathematics 2020-04-22 Zhenning Cai , Yana Di , Xiaoyu Dong

The complex Langevin method is a promising approach to the complex-action problem based on a fictitious time evolution of complexified dynamical variables under the influence of a Gaussian noise. Although it is known to have a restricted…

High Energy Physics - Lattice · Physics 2017-01-04 Keitaro Nagata , Jun Nishimura , Shinji Shimasaki

The complex Langevin method (CLM) is a promising tool to address the sign problem in quantum field theories with complex actions. However, it can converge to incorrect results even when simulations appear stable, highlighting the need for…

High Energy Physics - Lattice · Physics 2026-03-27 Anosh Joseph , Arpith Kumar

We employ the Complex Langevin method for simulation of complex-valued actions. First, we show how to test for convergence of the method by explicitely computing boundary terms and demonstrate this in a model. Then we investigate the…

High Energy Physics - Lattice · Physics 2018-10-30 Manuel Scherzer , Erhard Seiler , Dénes Sexty , Ion-Olimpiu Stamatescu

I review the status of the Complex Langevin method, which was invented to make simulations of models with complex action feasible. I discuss the mathematical justification of the procedure, as well as its limitations and open questions.…

High Energy Physics - Lattice · Physics 2018-04-18 Erhard Seiler

It is well known that investigating QCD at finite density by standard Monte Carlo methods is extremely difficult due to the sign problem. Some years ago, the complex Langevin method with gauge cooling was shown to work at high temperature,…

High Energy Physics - Lattice · Physics 2019-01-15 Keitaro Nagata , Jun Nishimura , Shinji Shimasaki

Simulations of full QCD at nonzero baryon density using light quark masses are presented. The sign problem is evaded by the usage of the complex Langevin equation. The simulations are stabilized by the gauge cooling procedure for small…

High Energy Physics - Lattice · Physics 2013-10-24 Denes Sexty

We present the results of continuum-extrapolated lattice simulations of quantum chromodynamics (QCD) above the crossover temperature and for unprecedentedly high baryon densities at the physical point, employing the complex Langevin…

High Energy Physics - Lattice · Physics 2026-04-22 Michael Mandl , Dénes Sexty , Daniel Unterhuber

We continue our simulations of lattice QCD at finite quark-number chemical potential, $\mu$, using the complex-Langevin equation (CLE) with gauge-cooling and adaptive updating. The CLE is used because QCD at finite finite $\mu$ has a…

High Energy Physics - Lattice · Physics 2019-10-28 D. K. Sinclair , J. B. Kogut

Complex Langevin simulations allow numerical studies of theories that exhibit a sign problem, such as QCD, and are thereby potentially suitable to determine the QCD phase diagram from first principles. Here we study QCD in the limit of…

High Energy Physics - Lattice · Physics 2016-10-12 Gert Aarts , Felipe Attanasio , Benjamin Jäger , Dénes Sexty

Lattice QCD at non-vanishing chemical potential is studied using the complex Langevin equation (CLE). One of the conditions for the correctness of the results of the CLE is that the zeroes of the measure coming from the fermionic…

High Energy Physics - Lattice · Physics 2016-11-10 G. Aarts , E. Seiler , D. Sexty , I. -O. Stamatescu

We outline a simple way to include heavy quark vacuum polarization in lattice QCD simulations. The method, based on effective field theory, requires only a trivial modification of the gluon action and has no impact on simulation times. We…

High Energy Physics - Lattice · Physics 2007-05-23 Matthew Nobes

We present the reweighted complex Langevin method, which enlarges the applicability range of the complex Langevin method by reweighting the complex trajectories. In this reweighting procedure both the auxiliary and target ensembles have a…

High Energy Physics - Lattice · Physics 2017-01-06 Jacques Bloch , Johannes Meisinger , Sebastian Schmalzbauer

We summarise recent progress in simulating QCD at nonzero baryon density using complex Langevin dynamics. After a brief outline of the main idea, we discuss gauge cooling as a means to control the evolution. Subsequently we present a status…

High Energy Physics - Lattice · Physics 2014-12-03 Gert Aarts , Felipe Attanasio , Benjamin Jäger , Erhard Seiler , Denes Sexty , Ion-Olimpiu Stamatescu