Robert Juhasz - Academia.edu (original) (raw)
Papers by Robert Juhasz
We study a system composed of two parallel totally asymmetric simple exclusion processes with ope... more We study a system composed of two parallel totally asymmetric simple exclusion processes with open boundaries, where the particles move in the two lanes in opposite directions and are allowed to jump to the other lane with rates inversely proportional to the length of the system. Stationary density profiles are determined and the phase diagram of the model is constructed in the hydrodynamic limit, by solving the differential equations describing the steady state of the system, analytically for vanishing total current and numerically for nonzero total current. The system possesses phases with a localized shock in the density profile in one of the lanes, similarly to exclusion processes endowed with nonconserving kinetics in the bulk. Besides, the system undergoes a discontinuous phase transition, where coherently moving delocalized shocks emerge in both lanes and the fluctuation of the global density is described by an unbiased random walk. This phenomenon is analogous to the phase coexistence observed at the coexistence line of the totally asymmetric simple exclusion process, however, as a consequence of the interaction between lanes, the density profiles are deformed and in the case of asymmetric lane change, the motion of the shocks is confined to a limited domain.
We consider the critical and off-critical properties at the boundary of the random transversefiel... more We consider the critical and off-critical properties at the boundary of the random transversefield Ising spin chain when the distribution of the couplings and/or transverse fields, at a distance l from the surface, deviates from its uniform bulk value by terms of order l −κ with an amplitude A. Exact results are obtained using a correspondence between the surface magnetization of the model and the surviving probability of a random walk with time-dependent absorbing boundary conditions. For slow enough decay, κ < 1/2, the inhomogeneity is relevant: Either the surface stays ordered at the bulk critical point or the average surface magnetization displays an essential singularity, depending on the sign of A. In the marginal situation, κ = 1/2, the average surface magnetization decays as a power law with a continuously varying, A-dependent, critical exponent which is obtained analytically. The behavior of the critical and off-critical autocorrelation functions as well as the scaling form of the probability distributions for the surface magnetization and the first gaps are determined through a phenomenological scaling theory. In the Griffiths phase, the properties of the Griffiths-McCoy singularities are not affected by the inhomogeneity. The various results are checked using numerical methods based on a mapping to free fermions. 05.50.+q, 64.60.Fr, 68.35.Rh
We consider nonequilibrium phase transitions in weighted scale-free networks, in which highly con... more We consider nonequilibrium phase transitions in weighted scale-free networks, in which highly connected nodes, which are created earlier in time are partially immunized. For epidemic spreading we solve the dynamical mean-field equations and discuss finite-size scaling theory. The theoretical predictions are confronted with the results of large scale Monte Carlo simulations on the weighted Barabási-Albert network. Local scaling exponents are found different at a typical site and at a node with very large connectivity.
Készítette: Juhász Róbert osztályvezető, a CSMKH elektronikus információbiztonsági vezetője Jól m... more Készítette: Juhász Róbert osztályvezető, a CSMKH elektronikus információbiztonsági vezetője Jól működő elektronikus információs rendszerek nélkül nem létezik modern közigazgatás; ugyanakkor az ezek által tárolt és kezelt adatok biztonságát is kiemelten kell kezelni. Központi intézkedésként a megfelelő információbiztonság kialakítását az állami és önkormányzati szervek elektronikus információbiztonságáról szóló 2013. évi L. törvény (Ibtv.) szabályozza, emellett az elmúlt időszakban számos új, az elektronikus információbiztonságot érintő jogszabály került kihirdetésre, melyek egy része már hatályba lépett, a többi része pedig a közeljövőben lép hatályba.
We study a system composed of two parallel totally asymmetric simple exclusion processes with ope... more We study a system composed of two parallel totally asymmetric simple exclusion processes with open boundaries, where the particles move in the two lanes in opposite directions and are allowed to jump to the other lane with rates inversely proportional to the length of the system. Stationary density profiles are determined and the phase diagram of the model is constructed in the hydrodynamic limit, by solving the differential equations describing the steady state of the system, analytically for vanishing total current and numerically for nonzero total current. The system possesses phases with a localized shock in the density profile in one of the lanes, similarly to exclusion processes endowed with nonconserving kinetics in the bulk. Besides, the system undergoes a discontinuous phase transition, where coherently moving delocalized shocks emerge in both lanes and the fluctuation of the global density is described by an unbiased random walk. This phenomenon is analogous to the phase coexistence observed at the coexistence line of the totally asymmetric simple exclusion process, however, as a consequence of the interaction between lanes, the density profiles are deformed and in the case of asymmetric lane change, the motion of the shocks is confined to a limited domain.
We consider the critical and off-critical properties at the boundary of the random transversefiel... more We consider the critical and off-critical properties at the boundary of the random transversefield Ising spin chain when the distribution of the couplings and/or transverse fields, at a distance l from the surface, deviates from its uniform bulk value by terms of order l −κ with an amplitude A. Exact results are obtained using a correspondence between the surface magnetization of the model and the surviving probability of a random walk with time-dependent absorbing boundary conditions. For slow enough decay, κ < 1/2, the inhomogeneity is relevant: Either the surface stays ordered at the bulk critical point or the average surface magnetization displays an essential singularity, depending on the sign of A. In the marginal situation, κ = 1/2, the average surface magnetization decays as a power law with a continuously varying, A-dependent, critical exponent which is obtained analytically. The behavior of the critical and off-critical autocorrelation functions as well as the scaling form of the probability distributions for the surface magnetization and the first gaps are determined through a phenomenological scaling theory. In the Griffiths phase, the properties of the Griffiths-McCoy singularities are not affected by the inhomogeneity. The various results are checked using numerical methods based on a mapping to free fermions. 05.50.+q, 64.60.Fr, 68.35.Rh
We consider nonequilibrium phase transitions in weighted scale-free networks, in which highly con... more We consider nonequilibrium phase transitions in weighted scale-free networks, in which highly connected nodes, which are created earlier in time are partially immunized. For epidemic spreading we solve the dynamical mean-field equations and discuss finite-size scaling theory. The theoretical predictions are confronted with the results of large scale Monte Carlo simulations on the weighted Barabási-Albert network. Local scaling exponents are found different at a typical site and at a node with very large connectivity.
Készítette: Juhász Róbert osztályvezető, a CSMKH elektronikus információbiztonsági vezetője Jól m... more Készítette: Juhász Róbert osztályvezető, a CSMKH elektronikus információbiztonsági vezetője Jól működő elektronikus információs rendszerek nélkül nem létezik modern közigazgatás; ugyanakkor az ezek által tárolt és kezelt adatok biztonságát is kiemelten kell kezelni. Központi intézkedésként a megfelelő információbiztonság kialakítását az állami és önkormányzati szervek elektronikus információbiztonságáról szóló 2013. évi L. törvény (Ibtv.) szabályozza, emellett az elmúlt időszakban számos új, az elektronikus információbiztonságot érintő jogszabály került kihirdetésre, melyek egy része már hatályba lépett, a többi része pedig a közeljövőben lép hatályba.