431 research outputs found

    Gauged supersymmetries in Yang-Mills theory

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    In this paper we show that Yang-Mills theory in the Curci-Ferrari-Delbourgo-Jarvis gauge admits some up to now unknown local linear Ward identities. These identities imply some non-renormalization theorems with practical simplifications for perturbation theory. We show in particular that all renormalization factors can be extracted from two-point functions. The Ward identities are shown to be related to supergauge transformations in the superfield formalism for Yang-Mills theory. The case of non-zero Curci-Ferrari mass is also addressed.Comment: 11 pages. Minor changes. Some added reference

    An Infrared Safe perturbative approach to Yang-Mills correlators

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    We investigate the 2-point correlation functions of Yang-Mills theory in the Landau gauge by means of a massive extension of the Faddeev-Popov action. This model is based on some phenomenological arguments and constraints on the ultraviolet behavior of the theory. We show that the running coupling constant remains finite at all energy scales (no Landau pole) for d>2d>2 and argue that the relevant parameter of perturbation theory is significantly smaller than 1 at all energies. Perturbative results at low orders are therefore expected to be satisfactory and we indeed find a very good agreement between 1-loop correlation functions and the lattice simulations, in 3 and 4 dimensions. Dimension 2 is shown to play the role of an upper critical dimension, which explains why the lattice predictions are qualitatively different from those in higher dimensions.Comment: 16 pages, 7 figures, accepted for publication in PR

    Critical thermodynamics of three-dimensional chiral model for N > 3

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    The critical behavior of the three-dimensional NN-vector chiral model is studied for arbitrary NN. The known six-loop renormalization-group (RG) expansions are resummed using the Borel transformation combined with the conformal mapping and Pad\'e approximant techniques. Analyzing the fixed point location and the structure of RG flows, it is found that two marginal values of NN exist which separate domains of continuous chiral phase transitions N>Nc1N > N_{c1} and NN>Nc2N N > N_{c2} where such transitions are first-order. Our calculations yield Nc1=6.4(4)N_{c1} = 6.4(4) and Nc2=5.7(3)N_{c2} = 5.7(3). For N>Nc1N > N_{c1} the structure of RG flows is identical to that given by the ϵ\epsilon and 1/N expansions with the chiral fixed point being a stable node. For N<Nc2N < N_{c2} the chiral fixed point turns out to be a focus having no generic relation to the stable fixed point seen at small ϵ\epsilon and large NN. In this domain, containing the physical values N=2N = 2 and N=3N = 3, phase trajectories approach the fixed point in a spiral-like manner giving rise to unusual crossover regimes which may imitate varying (scattered) critical exponents seen in numerous physical and computer experiments.Comment: 12 pages, 3 figure

    Regulation of proliferating cell nuclear antigen ubiquitination in mammalian cells

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    After exposure to DNA-damaging agents that block the progress of the replication fork, monoubiquitination of proliferating cell nuclear antigen (PCNA) mediates the switch from replicative to translesion synthesis DNA polymerases. We show that in human cells, PCNA is monoubiquitinated in response to methyl methanesulfonate and mitomycin C, as well as UV light, albeit with different kinetics, but not in response to bleomycin or camptothecin. Cyclobutane pyrimidine dimers are responsible for most of the PCNA ubiquitination events after UV-irradiation. Failure to ubiquitinate PCNA results in substantial sensitivity to UV and methyl methanesulfonate, but not to camptothecin or bleomycin. PCNA ubiquitination depends on Replication Protein A (RPA), but is independent of ATR-mediated checkpoint activation. After UV-irradiation, there is a temporal correlation between the disappearance of the deubiquitinating enzyme USP1 and the presence of PCNA ubiquitination, but this correlation was not found after chemical mutagen treatment. By using cells expressing photolyases, we are able to remove the UV lesions, and we show that PCNA ubiquitination persists for many hours after the damage has been removed. We present a model of translesion synthesis behind the replication fork to explain the persistence of ubiquitinated PCNA

    Spin Stiffness of Stacked Triangular Antiferromagnets

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    We study the spin stiffness of stacked triangular antiferromagnets using both heat bath and broad histogram Monte Carlo methods. Our results are consistent with a continuous transition belonging to the chiral universality class first proposed by Kawamura.Comment: 5 pages, 7 figure

    Critical behavior of frustrated systems: Monte Carlo simulations versus Renormalization Group

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    We study the critical behavior of frustrated systems by means of Pade-Borel resummed three-loop renormalization-group expansions and numerical Monte Carlo simulations. Amazingly, for six-component spins where the transition is second order, both approaches disagree. This unusual situation is analyzed both from the point of view of the convergence of the resummed series and from the possible relevance of non perturbative effects.Comment: RevTex, 10 pages, 3 Postscript figure

    Monte Carlo renormalization group study of the Heisenberg and XY antiferromagnet on the stacked triangular lattice and the chiral ϕ4\phi^4 model

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    With the help of the improved Monte Carlo renormalization-group scheme, we numerically investigate the renormalization group flow of the antiferromagnetic Heisenberg and XY spin model on the stacked triangular lattice (STA-model) and its effective Hamiltonian, 2N-component chiral ϕ4\phi^4 model which is used in the field-theoretical studies. We find that the XY-STA model with the lattice size 126×144×126126\times 144 \times 126 exhibits clear first-order behavior. We also find that the renormalization-group flow of STA model is well reproduced by the chiral ϕ4\phi^4 model, and that there are no chiral fixed point of renormalization-group flow for N=2 and 3 cases. This result indicates that the Heisenberg-STA model also undergoes first-order transition.Comment: v1:15 pages, 15 figures v2:updated references v3:added comments on the higher order irrelevant scaling variables v4:added results of larger sizes v5:final version to appear in J.Phys.Soc.Jpn Vol.72, No.

    Circles of coastal sustainability: a framework for coastal management

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    © 2020 by the authors. The coastal zone is a space where many social, economic, and political activities intersect with natural processes. In this paper, we present an adaptation of the method of ‘Circles of Sustainability’, used to provide a visual assessment of indicators that define sustainability profiles for cities. It is used as a basis for a ‘Circles of Coastal Sustainability’ (CCS) framework that can be used at multiple spatial scales to assess indicators of critical processes that facilitate/constrain sustainability of the world’s coastal zones. The development of such a framework can support management by identifying key features that influence environmental sustainability and human well-being. CCS presents a holistic assessment of four interdependent boundary domains: Environment and Ecology, Social and Cultural, Economics, and Governance and Policy. This approach improves its utility and usability for decision-makers and researchers. CCS adds to existing assessment frameworks that are often focused on particular themes and/or domains that confine their utility to the context of sustainable development and the UN Agenda 2030 Sustainable Development Goals, which demand an inherently holistic and integrated evaluation. CCS is a holistic framework designed to assess the boundaries to sustainability for socio-ecological systems at multiple scales for the world’s coasts.Erasmus Mundus programme Water and Coastal Managemen

    Optimization of the derivative expansion in the nonperturbative renormalization group

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    We study the optimization of nonperturbative renormalization group equations truncated both in fields and derivatives. On the example of the Ising model in three dimensions, we show that the Principle of Minimal Sensitivity can be unambiguously implemented at order 2\partial^2 of the derivative expansion. This approach allows us to select optimized cut-off functions and to improve the accuracy of the critical exponents ν\nu and η\eta. The convergence of the field expansion is also analyzed. We show in particular that its optimization does not coincide with optimization of the accuracy of the critical exponents.Comment: 13 pages, 9 PS figures, published versio
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