arXiv subjects

G. Szabo

Publications and source records attributed to G. Szabo.

8 recordsLinked to original sources

arXiv2016

Plasmonic structure integrated single-photon detectors optimized to maximize polarization contrast

Numerical optimization was performed via COMSOL Multiphysics to maximize the polarization contrast of superconducting nanowire single photon detectors (SNSPDs). SNSPDs were integrated with four different types of one-dimensional periodic plasmonic structures capable of mediating p-polarized photon selectivity to the niobium-nitride superconducting nanowire pattern. Optimization with two different criteria regarding the maximal tilting resulted in wavelength-scaled periodic integrated structures, which have different geometrical parameters, and exhibit different polar angle dependent optical response and dispersion characteristics, as well as accompanying near-field phenomena at the extrema. Polarization contrast of 6.37*10^2 and 3.28*10^2 - 6.86*10^11 and 1.42*10^11 - 1.81*10^13 and 7.87*10^12 - 1.90*10^3 and 1.15*10^5 can be achieved in nanocavity-, nanocavity-deflector-, nanocavity-double-deflector-, nanocavity-trench-array-integrated P-SNSPDs optimized with 85 degree and 80 degree criterion regarding the maximal tilting.

physics.optics↗

arXiv2008

Diversity of reproduction rate supports cooperation in the prisoner's dilemma game on complex networks

In human societies the probability of strategy adoption from a given person may be affected by the personal features. Now we investigate how an artificially imposed restricted ability to reproduce, overruling ones fitness, affects an evolutionary process. For this purpose we employ the evolutionary prisoner's dilemma game on different complex graphs. Reproduction restrictions can have a facilitative effect on the evolution of cooperation that sets in irrespective of particularities of the interaction network. Indeed, an appropriate fraction of less fertile individuals may lead to full supremacy of cooperators where otherwise defection would be widespread. By studying cooperation levels within the group of individuals having full reproduction capabilities, we reveal that the recent mechanism for the promotion of cooperation is conceptually similar to the one reported previously for scale-free networks. Our results suggest that the diversity in the reproduction capability, related to inherently different attitudes of individuals, can enforce the emergence of cooperative behavior among selfish competitors.

q-bio.PE↗

arXiv2008

Self-organizing patterns maintained by competing associations in a six-species predator-prey model

Formation and competition of associations are studied in a six-species ecological model where each species has two predators and two prey. Each site of a square lattice is occupied by an individual belonging to one of the six species. The evolution of the spatial distribution of species is governed by iterated invasions between the neighboring predator-prey pairs with species specific rates and by site exchange between the neutral pairs with a probability $X$. This dynamical rule yields the formation of five associations composed of two or three species with proper spatiotemporal patterns. For large $X$ a cyclic dominance can occur between the three two-species associations whereas one of the two three-species associations prevails in the whole system for low values of $X$ in the final state. Within an intermediate range of $X$ all the five associations coexist due to the fact that cyclic invasions between the two-species associations reduce their resistance temporarily against the invasion of three-species associations.

q-bio.PE↗

arXiv2006

Network effects in service usage

While there is ample evidence that social and communication networks play a key role during the spread of new ideas, products, or services, network effects are expected to have diminished influence in the stationary state, when all users are aware of the innovation, and its usage pattern is determined mainly by its utility to the user. Here we study four mobile phone-based services available to over six million subscribers, allowing us to simultaneously monitor the communication network between individuals and the time-resolved service usage patterns. We find that usage highly correlates with the structure of the communication network, and demonstrate the coexistence on the same social network of two distinct usage classes, network effects being responsible for the quantifiable differences between them. To test the predictive power of our theory, we demonstrate that traditional marketing techniques are ineffective in permanently boosting service adoption, and propose a hub-based incentive mechanism that has the potential to enhance usage for one of the two service classes.

physics.soc-ph↗

arXiv2006

Structure and tie strengths in mobile communication networks

Electronic databases, from phone to emails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure of a society-wide communication network. We observe a coupling between interaction strengths and the network's local structure, with the counterintuitive consequence that social networks are robust to the removal of the strong ties, but fall apart following a phase transition if the weak ties are removed. We show that this coupling significantly slows the diffusion process, resulting in dynamic trapping of information in communities, and find that when it comes to information diffusion, weak and strong ties are both simultaneously ineffective.

physics.soc-ph↗

arXiv2004

Vertex dynamics during domain growth in three-state models

Topological aspects of interfaces are studied by comparing quantitatively the evolving three-color patterns in three different models, such as the three-state voter, Potts and extended voter models. The statistical analysis of some geometrical features allows to explore the role of different elementary processes during distinct coarsening phenomena in the above models.

cond-mat.stat-mech↗

arXiv2003

Color Variability of Asteroids in SDSS Moving Object Catalog

We report a detection of statistically significant color variations for a sample of 7,531 multiply observed asteroids that are listed in the Sloan Digital Sky Survey Moving Object Catalog. Using 5-band photometric observations accurate to ~0.02 mag, we detect color variations in the range 0.06-0.11 mag (rms). These variations appear uncorrelated with asteroids physical characteristics such as diameter (in the probed 1-10 km range), taxonomic class, and family membership. Despite such a lack of correlation, which implies a random nature for the cause of color variability, a suite of tests suggest that the detected variations are not instrumental effects. In particular, the observed color variations are incompatible with photometric errors, and, for objects observed at least four times, the color change in the first pair of observations is correlated with the color change in the second pair. These facts strongly suggest that the observed effect is real, and also indicate that for some asteroids color variations are larger than for others. The detected color variations can be explained as due to inhomogeneous albedo distribution over an asteroid surface. Although relatively small, these variations suggest that fairly large patches with different color than their surroundings exist on a significant fraction of asteroids. This conclusion is in agreement with spatially resolved color images of several large asteroids obtained by NEAR spacecraft and HST.

astro-ph↗

arXiv2001

Defensive alliances in spatial models of cyclical population interactions

As a generalization of the 3-strategy Rock-Scissors-Paper game dynamics in space, cyclical interaction models of six mutating species are studied on a square lattice, in which each species is supposed to have two dominant, two subordinated and a neutral interacting partner. Depending on their interaction topologies, these systems can be classified into four (isomorphic) groups exhibiting significantly different behaviors as a function of mutation rate. On three out of four cases three (or four) species form defensive alliances which maintain themselves in a self-organizing polydomain structure via cyclic invasions. Varying the mutation rate this mechanism results in an ordering phenomenon analogous to that of magnetic Ising model.

cond-mat.stat-mech↗