Effects of multiplicative noise in relativistic phase transitions

Antunes, Nuno D.; Gandra, Pedro; Rivers, R. J.

doi:10.1103/physrevd.71.105006

Cited by 6 publications

(6 citation statements)

References 35 publications

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“…Starting with the high-dissipation results with α = 1.0, we see that within error-bars, the scaling exponent is approximately constant for β < 0.5. The value measured σ = 0.28, coincides with that obtained for similar simulation parameters in the case of a single field system [48]. One should note that the method used to determine the final defect density is known to lead to a slight over-estimate in σ when compared to other, computationally more demanding, approaches (for a discussion see [12]).…”

Section: Numerical Simulations Of Defect Formationsupporting

confidence: 78%

“…The relation between these two terms ensures that the fluctuation-dissipation theorem is satisfied and guarantees that for very large times thermal equilibrium at temperature Γ/2 is reached. A simpler version of this model with one single field has been used successfully in several studies of defect formation in 1+1 dimensions [12,48]; we refer the reader to these for more a detailed discussion of the model and its numerical implementation.…”

Section: Numerical Simulations Of Defect Formationmentioning

confidence: 99%

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Creation of defects with core condensation

et al. 2006

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Defects in superfluid3 He, high-Tc superconductors, QCD colour superfluids and cosmic vortons can possess (anti)ferromagnetic cores, and their generalisations. In each case there is a second order parameter whose value is zero in the bulk which does not vanish in the core. We examine the production of defects in the simplest 1+1 dimensional scalar theory in which a second order parameter can take non-zero values in a defect core. We study in detail the effects of core condensation on the defect production mechanism.

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Section: Numerical Simulations Of Defect Formationsupporting

confidence: 78%

Section: Numerical Simulations Of Defect Formationmentioning

confidence: 99%

Creation of defects with core condensation

et al. 2006

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“…The existence of these additional terms in the GLL equation will, of course, play an important role in the dynamics of the formation of condensates. For instance, it was shown that the effects of multiplicative noise are rather significant in the Kibble-Zurek scenario of defect formation in one spatial dimension [18]. Although in the literature there are many different approaches for studying the nonequilibrium dynamics in field theory [19,20,21], the use of stochastic Langevin-like equations of motion is still a simpler and more direct approach in many different contexts in statistical physics and field theory in general.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Langevin simulation of scalar fields: Additive and multiplicative noises and lattice renormalization

Cassol-Seewald

Farias

Fraga

et al. 2012

Physica A: Statistical Mechanics and its Applications

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“…To assess the effect of the new contributions on the relevant time scales for phase ordering, we consider a scalar λ φ 4 theory in the broken phase. It was shown recently that the effects of multiplicative noise are rather significant in the Kibble-Zurek scenario of defect formation in one spatial dimension [14]. We perform (3 + 1)-dimensional real-time lattice simulations to study the behavior of the inhomogeneous scalar field, taking into account lattice counter-terms that guarantee lattice-size independence [15,16,17].…”

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confidence: 99%

Improved Langevin Approach to Spinodal Decomposition in the Chiral Transition

Fraga¹,

Krein²,

Ramos³

2006

AIP Conference Proceedings

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Abstract.We use an improved Langevin description that incorporates both additive and multiplicative noise terms to study the dynamics of phase ordering. We perform real-time lattice simulations to investigate the role played by different contributions to the dissipation and noise. Lattice-size independence is assured by the use of appropriate lattice counterterms.Keywords: QCD phase transition; Heavy-ion collisions; Dissipation in field theory PACS: 11.30.Rd , 64.90.+b The dynamics of spinodal decomposition after a phase transition in field theory plays a major role in physics, for instance in the nonequilibrium time evolution of order parameters [1]. The influence of the presence of a hot and dense medium on the dynamics of particles and fields is encoded "macroscopically" in attributes such as dissipation and noise, and can dramatically affect the relevant time scales for different stages of phase conversion. In particular, in high-energy heavy ion collisions, where one presumably forms a hot, dense, strongly interacting quark-gluon plasma [2], chiral fields evolve under extreme conditions of temperature and density during the QCD phase transition. To have a clear understanding of data coming from BNL-RHIC, and especially of data that will be produced at CERN-LHC, one needs a realistic description of the hierarchy of scales associated with dissipation, noise, radiation, expansion and finite size of the system. Recently, some of us have considered the effects of dissipation in the scenario of explosive spinodal decomposition for hadron production [3,4,5,6,7] during the QCD transition after a high-energy heavy ion collision in the simplest fashion [8]. Using a phenomenological Langevin description for the time evolution of the order parameter in a chiral effective model [9], inspired by microscopic nonequilibrium field theory results [10,11,12], we performed real-time lattice simulations for the behavior of the inhomogeneous chiral fields. It was shown that the effects of dissipation could be dramatic in spite of very conservative assumptions: even if the system quickly reaches the unstable region there is still no guarantee that it will explode. The framework for the dynamics was assumed to be given by the following Langevin equation:

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Effects of multiplicative noise in relativistic phase transitions

Cited by 6 publications

References 35 publications

Creation of defects with core condensation

Creation of defects with core condensation

Langevin simulation of scalar fields: Additive and multiplicative noises and lattice renormalization

Improved Langevin Approach to Spinodal Decomposition in the Chiral Transition

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