Person: Muñoz Sudupe, Antonio
Universidad Complutense de Madrid
Faculty / Institute
Now showing 1 - 10 of 51
PublicationPerturbative Ward identities for Yang-Mills field theory stochastically quantized(Amer Physical Soc, 1986-04-15) Muñoz Sudupe, Antonio%'e compute the divergent part of the three-point vertex function of the non-Abelian Yang-Mills gauge field theory within the stochastic quantization approach to the one-loop order. This calculation allows us to find four renormalization constants which, together with the four previously obtained, verify, to the calculated order, some Ward identities. PublicationNew universality class in three dimensions? The antiferromagnetic RP^(2) model(Elsevier Science BV, 1996-06-20) Ballesteros, H. G.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, AntonioWe present the results of a Monte Carlo simulation of the RP^(2) model in three dimensions with negative coupling. We observe a second order phase transition between the disordered phase and an antiferromagnetic, unfrustrated, ordered one. We measure, with a finite size scaling analysis, the thermal exponent, obtaining v = 0.784(g). We have found two magnetic-type relevant operators whose related YJ exponents are 0.038( 2) and 1.338( 8) respectively. PublicationStudy of the Coulomb-Higgs transition in the abelian Higgs model(Elsevier Science BV, 1998-01-01) Cruz, A.; Íñiguez, D.; Fernández Pérez, Luis Antonio; Muñoz Sudupe, Antonio; Tarancón, A.The order of the Coulomb-Higgs transition in the U (1) -Higgs model with unfrozen modulus of the scalar field is studied. Large lattices (up to 24^4 in one case) and high statistics are used. We fix β = 1.15 and explore specially a region of λ-values where metastability is observed. We study the thermodynamical limit of several observables, in particular, the latent heat, the specific heat, the decrement of the free energy between the maxima and the central minimum of the two-peaked histogram, the Binder cumulant and the displacement of the critical coupling with the lattice size. The results point towards a second order transition for λ ≥ 0.005, while for smaller values of λ the strong metastability growing with the lattice size seems to derive from a first order character. PublicationCritical behavior in the site-diluted three-dimensional three-state Potts model(American Physical Society, 2000-02-01) Ballesteros, H. G.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, Antonio; Parisi, G.; Ruiz Lorenzo, J. J.We have studied numerically the effect of quenched site dilution on a weak first-order phase transition in three dimensions. We have simulated the site diluted three-states Potts model studying in detail the secondorder region of its phase diagram. We have found that the n exponent is compatible with the one of the three-dimensional diluted Ising model, whereas the h exponent is definitely different. PublicationMonte Carlo study of O(3) antiferromagnetic models in three dimensions(American Physical Society, 1996-02-01) Ballesteros, H. G.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, AntonioWe study three antiferromagnetic formulations of the O(3) spin model in three dimensions by means of Monte Carlo simulations: (1) a two parameter s model with nearest- and next-nearest neighbors couplings in a cubic lattice; (2) a face-centered-cubic lattice with nearest-neighbor interaction; (3) a cubic lattice with a set of fully frustrating couplings. We discuss in all cases the vacua properties and analyze the phase transitions. Using finite-size scaling analysis we conclude that all phase transitions found are of first order. PublicationNonequilibrium spin glass dynamics with Janus(American Institute of Physics, 2009) Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, Antonio; Yllanes, D.; otros, ...The out of equilibrium evolution for an Edwards‐Anderson spin glass is followed for a tenth of a second, a long enough time to let us make safe predictions about the behaviour at experimental scales. This work has been made possible by Janus, an FPGA based special purpose computer. We have thoroughly studied the spin glass correlation functions and the growth of the coherence length for L = 80 lattices in 3D. Our main conclusion is that these spin glasses follow noncoarsening dynamics, at least up to the experimentally relevant time scales. PublicationCritical properties of the antiferromagnetic RP^2 model in three dimensions(Elsevier, 1997-01-13) Ballesteros, H. G.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, AntonioWe study the behavior of the antiferromagnetic RP^2 model in d = 3. The vacuum structure is analyzed in the critical and low temperature regions, paying special attention to the spontaneous symmetry breaking pattern. Near the critical point we observe a full breakdown of the 0(3) symmetry of the action. Several methods for computing critical exponents are compared. We conclude that the most solid determination is obtained using a measure of the correlation length. Corrections-to-scaling are parameterized, yielding a very accurate determination of the critical coupling and a 5% error measure of the related exponent. This is used to estimate the systematic errors due to finite-size effects. PublicationIs the antiferromagnetic RP^(2) model in four dimensions trivial?(Amer Physical Soc, 1997-04-15) Ballesteros, H. G.; Carmona, J. M.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, Antonio; Tarancón, A.We study the antiferromagnetic RP^(2) model in four dimensions. We find a second order transition with two order parameters, one ferromagnetic and the other antiferromagnetic. The antiferromagnetic sector has mean- field critical exponents and a renormalized coupling which goes to zero in the continuum limit. The exponents of the ferromagnetic channel are not the mean-field ones, but the difference can be interpreted as logarithmic corrections. We perform a detailed analysis of these corrections and conclude the triviality of the continuum limit of this model. PublicationJanus: an FPGA-based system for high-performance scientific computing(IEEE Computer Soc., 2009-01) Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, Antonio; Yllanes, D.; otros, ...This paper describes JANUS, a modular massively parallel and reconfigurable FPGA-based computing system. Each JANUS module has a computational core and a host. The computational core is a 4x4 array of FPGA-based processing elements with nearest-neighbor data links. Processors are also directly connected to an I/O node attached to the JANUS host, a conventional PC. JANUS is tailored for, but not limited to, the requirements of a class of hard scientific applications characterized by regular code structure, unconventional data manipulation instructions and not too large data-base size. We discuss the architecture of this configurable machine, and focus on its use on Monte Carlo simulations of statistical mechanics. On this class of application JANUS achieves impressive performances: in some cases one JANUS processing element outperfoms high-end PCs by a factor ≈1000. We also discuss the role of JANUS on other classes of scientific applications. PublicationMatching microscopic and macroscopic responses in glasses(American Physical Society, 2017-04-13) Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, AntonioWe first reproduce on the Janus and Janus II computers a milestone experiment that measures the spinglass coherence length through the lowering of free-energy barriers induced by the Zeeman effect. Secondly, we determine the scaling behavior that allows a quantitative analysis of a new experiment reported in the companion Letter [S. Guchhait and R. Orbach, Phys. Rev. Lett. 118, 157203 (2017)]. The value of the coherence length estimated through the analysis of microscopic correlation functions turns out to be quantitatively consistent with its measurement through macroscopic response functions. Further, nonlinear susceptibilities, recently measured in glass-forming liquids, scale as powers of the same microscopic length.