arXiv subjects

Alessandro Pluchino

Publications and source records attributed to Alessandro Pluchino.

At least 19 recordsLinked to original sources

arXiv2024

Michelson-Morley Experiments: at the crossroads of Relativity, Cosmology and Quantum Physics

Quantum nonlocality would naturally fit into a version of relativity with a preferred reference system. However, acceptance of this idea has traditionally required experimental evidence. Namely, detecting in laboratory a small angular dependence of the velocity of light correlated to the cosmic motion of the Earth. Here, we summarize a new theoretical framework where the tiny, irregular residuals observed so far, from Michelson-Morley to current experiments of laser interferometry, can indeed be understood in terms of the Earth motion in the Cosmic Microwave Background observed directly with satellites in space. Our results, challenging the usual null interpretation, emphasize the central role of 'ether-drift' experiments for Relativity, Cosmology and Quantum Physics.

physics.gen-ph↗

arXiv2024

Early Career Wins and Tournament Prestige Characterize Tennis Players' Trajectories

Success in sports is a complex phenomenon that has only garnered limited research attention. In particular, we lack a deep scientific understanding of success in sports like tennis and the factors that contribute to it. Here, we study the unfolding of tennis players' careers to understand the role of early career stages and the impact of specific tournaments on players' trajectories. We employ a comprehensive approach combining network science and analysis of ATP tournament data and introduce a novel method to quantify tournament prestige based on the eigenvector centrality of the co-attendance network of tournaments. Focusing on the interplay between participation in central tournaments and players' performance, we find that the level of the tournament where players achieve their first win is associated with becoming a top player. This work sheds light on the critical role of the initial stages in the progression of players' careers, offering valuable insights into the dynamics of success in tennis.

physics.soc-ph↗

arXiv2023

The Paradox of Talent: how Chance affects Success in Tennis Tournaments

Individual sports competitions provide a natural setting for examining the relative importance of talent and luck/chance in achieving success. The belief that success is primarily due to individual abilities and hard work rather than external factors is particularly strong in this context. In this study, we test this belief using tennis as a case study, due to its popularity and competition structure in direct-elimination tournaments. Our dataset covers the decade 2010-2019 of main events in the ATP circuit and consists of tourney results and annual rankings for professional male players. After a preliminary data analysis, we introduce an agent-based model able to accurately simulate the tennis players' dynamics along several seasons. We show that, once calibrated on the dataset, the model is able to reproduce the main stylized facts observed in real data, including the results of single tournaments and the development of players' careers in the ATP community. The strength of our approach lies in its simplicity: it requires only one free parameter a to determine the importance of talent in scoring every single point: a = 1, if only talent matters; a = 0, if the outcome of each point is entirely due to chance. We find the best agreement between real data and simulation results when talent weights substantially less than luck, i.e. when a is between 0.20 and 0.30. A further comparison between data and simulations, based on the analysis of the direct networks of all the matches, confirms the previous finding. A posteriori, we notice that this surprisingly important role of chance in tennis tournaments is not an exception. On the contrary, it can be explained by a more general paradoxical effect that characterizes highly competitive environments, particularly in individual sports. In other words, when the difference in talent between top players is minimal, chance becomes determinant.

physics.soc-ph↗

arXiv2022

Quantum Non-Locality and the CMB: what Experiments say

"Non-Locality is most naturally incorporated into a theory in which there is a special frame of reference. One possible candidate for this special frame of reference is the one in which the Cosmic Microwave Background (CMB) is isotropic. However, other than the fact that a realistic interpretation of quantum mechanics requires a preferred frame and the CMB provides us with one, there is no readily apparent reason why the two should be linked" (L. Hardy). Starting from this remark we first argue that, given the present view of the vacuum, the basic tenets of Quantum Field Theory cannot guarantee that Einstein Special Relativity, with no preferred frame, is the physically realized version of relativity. Then, to try to understand the nature of the hypothetical preferred $Σ-$frame, we consider the so called ether-drift experiments, those precise optical measurements that try to detect in laboratory a small angular dependence of the two-way velocity of light and then to correlate this angular dependence with the direct CMB observations with satellites in space. By considering all experiments performed so far, from Michelson-Morley to the present experiments with optical resonators, and analyzing the small observed residuals in a modern theoretical framework, the long sought $Σ-$ frame tight to the CMB naturally emerges. Finally, if quantum non-locality reflects some effect propagating at vastly superluminal speed $v_{QI} \to \infty $, its ultimate origin could be hidden somewhere in the infinitely large speed $c_s \to \infty$ of the vacuum density fluctuations.

physics.gen-ph↗

arXiv2022

Pairwise and high-order dependencies in the cryptocurrency trading network

In this paper we analyse the effects of information flows in cryptocurrency markets. We first define a cryptocurrency trading network, i.e. the network made using cryptocurrencies as nodes and the Granger causality among their weekly log returns as links, later we analyse its evolution over time. In particular, with reference to years 2020 and 2021, we study the logarithmic US dollar price returns of the cryptocurrency trading network using both pairwise and high-order statistical dependencies, quantified by Granger causality and O-information, respectively. With reference to the former, we find that it shows peaks in correspondence of important events, like e.g., Covid-19 pandemic turbulence or occasional sudden prices rise. The corresponding network structure is rather stable, across weekly time windows in the period considered and the coins are the most influential nodes in the network. In the pairwise description of the network, stable coins seem to play a marginal role whereas, turning high-order dependencies, they appear in the highest number of synergistic information circuits, thus proving that they play a major role for high order effects. With reference to redundancy and synergy with the time evolution of the total transactions in US dollars, we find that their large volume in the first semester of 2021 seems to have triggered a transition in the cryptocurrency network toward a more complex dynamical landscape. Our results show that pairwise and high-order descriptions of complex financial systems provide complementary information for cryptocurrency analysis.

q-fin.TR↗

arXiv2022

Objective and perceived risk in seismic vulnerability assessment at urban scale

The assessment of seismic risk in urban areas with high seismicity is certainly one of the most important problems that territorial managers have to face. A reliable evaluation of this risk is the basis for the design of both specific seismic improvement interventions and emergency management plans. Unappropriate seismic risk assessments may provide misleading results and induce bad decisions with relevant economic and social impact. The seismic risk in urban areas is mainly linked to three factors, namely, "hazard", "exposure" and "vulnerability". Hazard measures the potential of an earthquake to produce harm; exposure evaluates the amount of population exposed to harm; vulnerability represents the proneness of considered buildings to suffer damages in case of an earthquake. Estimates of such factors may not always coincide with the perceived risk of the resident population. The propensity to implement structural seismic improvement interventions aimed at reducing the vulnerability of buildings depends significantly on the perceived risk. This paper investigates on the difference between objective and perceived risk and highlights some critical issues. The aim of this study is to calibrate opportune policies, which allow addressing the most appropriate seismic risk mitigation options with reference to current levels of perceived risk. We propose the introduction of a Seismic Policy Prevention index (SPPi). This methodology is applied to a case-study focused on a densely populated district of the city of Catania (Italy).

physics.soc-ph↗

arXiv2022

A dynamic model of Tax Evasion

In this paper we present a simplified model of a proportional taxation system where citizens decide whether to pay taxes or evade them. We initially derive a dynamic equation for the fraction of evaders and then present both its critical points and equilibrium stable states for a well-mixed population and for a fixed audit probability. Our theoretical predictions consider different possible income distributions (homogeneous and heterogeneous), time-dependent audit probability and different possible social topologies, by means of selected complex network configurations. All derived results are validated and confirmed by extended Monte Carlo simulations. Finally, some policy implications aimed to reduce tax evasion are suggested, with regards to the tax and fine rates and the audit probability.

physics.soc-ph↗

arXiv2021

Exploring the impact of mobility restrictions on the COVID-19 spreading through an agent-based approach

Mobility restriction is considered one of the main policies to contain COVID-10 spreading. However, there are multiple ways to reduce mobility via differentiated restrictions, and it is not easy to predict the actual impact on virus spreading. This is a limitation for policy-makers who need to implement effective and timely measures. Notwithstanding the big role of data analysis to understand this phenomenon, it is also important to have more general models capable of predicting the impact of different scenarios. Besides, they should be able to simulate scenarios in a disaggregated way, so to understand the possible impact of targeted strategies, e.g. on a geographical scale or in relation to other variables associated with the potential risk of infection. This paper presents an agent-based model (ABM) able to dynamically simulate the COVID-19 spreading under different mobility restriction scenarios. The model uses the Italian case study with its 20 administrative regions and considers parameters that can be attributed to the diffusion and lethality of the virus (based on a virus spread risk model) and population mobility patterns. The model is calibrated with real data and reproduces the impact that different mobility restrictions can have on the pandemic diffusion based on a combination of static and dynamic parameters. Results suggest that virus spreading would have been similar if differentiated mobility restriction strategies based on a-priori risk parameters instead of a national lockdown would have been put in place in Italy during the first wave of the pandemic. The proposed model could give useful suggestions for decision-makers to tackle pandemics and virus spreading at a strategic level.

physics.soc-ph↗

arXiv2020

On the origins of extreme wealth inequality in the Talent vs Luck Model

While wealth distribution in the world is highly skewed and heavy-tailed, human talent - as the majority of individual features - is normally distributed. In a recent computational study by Pluchino et al [Talent vs luck: The role of randomness in success and failure, Adv. Complex Syst. 21 (03-04) (2018) 1850014], it has been shown that the combined effects of both random external factors (lucky and unlucky events) and multiplicative dynamics in capital accumulation are able to clarify this apparent contradiction. We introduce here a simplified version (STvL) of the original Talent versus Luck (TvL) model, where only lucky events are present, and verify that its dynamical rules lead to the same very large wealth inequality as the original model. We also derive some analytical approximations aimed to capture the mechanism responsible for the creation of such wealth inequality from a Gaussian-distributed talent. Under these approximations, our analysis is able to reproduce quite well the results of the numerical simulations of the simplified model in special cases. On the other hand, it also shows that the complexity of the model lies in the fact that lucky events are transformed into an increase of capital with heterogeneous rates, which yields a non-trivial generalization of the role of multiplicative processes in generating wealth inequality, whose fully generic case is still not amenable to analytical computations.

physics.soc-ph↗

arXiv2020

Robustness of soil ecosystems under different regimes of management

In this study three soil ecosystems, that differ in the type of management, have been compared in the attempt to understand if and how anthropogenic action affects them. The structure of the corresponding food webs was analyzed and their robustness was calculated through the use of a dynamic model. With regard to the topology, it has been found that the structure of all three networks is small world. Furthermore, all three networks have a disassortative nature as expected for foodwebs. The values of the clustering coefficient, of the connectance and of the complexity, together with the calculation of the robustness suggest that the ecosystem related to a fallowed pastures with low pressure management is more robust than two ecosystems related to organic farms subject to middle intensity management. If the evidence suggested by this study was confirmed by further studies, the robustness shown by the networks could be useful for evaluating, from an ecological point of view, the sustainability of the agricultural practices to which the ecosystem is subject.

q-bio.PE↗

arXiv2019

Inequalities, chance and success in sport competitions: simulations vs empirical data

We present a new way of estimation of the role of chance in achieving success, by comparing the empirical data from 100-meter dash competitions (one of the sports disciplines with the most stringent controls of external randomness), with the results of an agent-based computer model, which assumes that success depends jointly on the intrinsic talent of the agent and on unpredictable luck. We find a small, but non-zero contribution of random luck to the performance of the best sprinters, which may serve as a lower bound for the randomness role in other, less stringently controlled competitive domains. Additionally we discuss the perception of the payoff differences among the top participants, and the role of random luck in the resulting inequality.

physics.soc-ph↗

arXiv2019

Why lot: How sortition came to help representative democracy

In this paper we discuss the problems of modern representative democracy and we look at the selection of legislators by lot as a way to tame some of the drawbacks of that system. It is recalled at the beginning that resorting to sortition for the selection of public officers used to be a popular way of taming factionalism in public affairs. Factionalism is assumed to be detrimental to public affairs as public officers may favour their own faction (a tribe or a party) instead of pursuing the general interest. Moreover they tend to overinvest in strengthening their power, thus engaging in power struggles with opposing factions, unlikely to benefit society. In this respect we present a new mathematical model aiming at describing a more efficient parliament where sortition is brought to bear. It will be shown that starting from a parliament working with two parties (or coalitions), where the costs of representative democracy are quite apparent through the detrimental effects of party discipline, one can beneficially move towards a parliament where independent legislators, randomly selected from the population of constituents, sit alongside elected members who belong to a party and are subjected to party discipline. The paper shows that increasing the number of independent legislators up to a point enhances the efficiency of the parliament and puts into check the factionalism likely to arise from party discipline.

physics.soc-ph↗

arXiv2019

Exploring the Role of Interdisciplinarity in Physics: Success, Talent and Luck

Although interdisciplinarity is often touted as a necessity for modern research, the evidence on the relative impact of sectorial versus to interdisciplinary science is qualitative at best. In this paper we leverage the bibliographic data set of the American Physical Society to quantify the role of interdisciplinarity in physics, and that of talent and luck in achieving success in scientific careers. We analyze a period of 30 years (1980-2009) tagging papers and their authors by means of the Physics and Astronomy Classification Scheme (PACS), to show that some degree of interdisciplinarity is quite helpful to reach success, measured as a proxy of either the number of articles or the citations score. We also propose an agent-based model of the publication-reputation-citation dynamics reproduces the trends observed in the APS data set. On the one hand, the results highlight the crucial role of randomness and serendipity in real scientific research; on the other, they shed light on a counter-intuitive effect indicating that the most talented authors are not necessarily the most successful ones.

physics.soc-ph↗

arXiv2018

Exploring the role of talent and luck in getting success

We review recent numerical results on the role of talent and luck in getting success by means of a schematic agent-based model. In general the role of luck is found to be very relevant in order to get success, while talent is necessary but not sufficient. Funding strategies to improve the success of the most talented people are also discussed.

physics.soc-ph↗

arXiv2018

Testing demand responsive shared transport services via agent-based simulations

Demand Responsive Shared Transport DRST services take advantage of Information and Communication Technologies ICT, to provide on demand transport services booking in real time a ride on a shared vehicle. In this paper, an agent-based model ABM is presented to test different the feasibility of different service configurations in a real context. First results show the impact of route choice strategy on the system performance.

cs.MA↗

arXiv2017

A multi-layer agent-based model for the analysis of energy distribution networks in urban areas

Significant research contributions and Directives approach the issue of the insertion of renewable-based energy systems on urban territory in order to face with the growing energy needs of citizens. The introduction of such systems gives raise to installers to both satisfy their energy demands and distribute eventual energy excesses to close neighbours. This paper presents a multi-layer agent-based computational model that simulates multiple event of the network of the energy distribution occurring within urban areas. The model runs on the NetLogo platform and aims at elaborating the most suitable strategy when dealing with the design of a network of energy distribution. Experimental data are discussed on the basis of two main scenarios within an operating period of 24 hours. Scenarios consider both the variation of the percentages of installers of renewable-based energy systems and the distance along which energy exchanges occur.

physics.soc-ph↗

arXiv2016

Finding shared decisions in stakeholder networks: an agent-based approach

We address the problem of a participatory decision-making process where a shared priority list of alternatives has to be obtained while avoiding inconsistent decisions. An agent-based model (ABM) is proposed to mimic this process in different social networks of stakeholders who interact according to an opinion dynamics model. Simulations' results show the efficacy of interaction in finding a transitive and, above all, shared decision. These findings are in agreement with real participation experiences regarding transport planning decisions and can give useful suggestions on how to plan an effective participation process for sustainable policy-making based on opinion consensus.

physics.soc-ph↗

arXiv2016

A multilayer approach for price dynamics in financial markets

We introduce a new Self-Organized Criticality (SOC) model for simulating price evolution in an artificial financial market, based on a multilayer network of traders. The model also implements, in a quite realistic way with respect to previous studies, the order book dy- namics, by considering two assets with variable fundamental prices. Fat tails in the probability distributions of normalized returns are observed, together with other features of real financial markets.

q-fin.TR↗