The Evolution of Trust and Trustworthiness

Published in Journal of the Royal Society Interface, 2020

Trust and trustworthiness form the basis for continued social and economic interactions, and they are also fundamental for cooperation, fairness, honesty, and indeed for many other forms of prosocial and moral behavior. However, trust entails risks, and building a trustworthy reputation requires effort. So how did trust and trustworthiness evolve, and under which conditions do they thrive? To find answers, we operationalize the concepts of trust and trustworthiness using the trust game with the trustor’s investment and the trustee’s return of the investment as the two key parameters. We report our findings in this paper and outline future directions which could help us improve our understanding of the origin and nature of trust.

Improved Upper Bounds on the Asymptotic Growth Velocity of Eden Clusters

Published in Journal of Statistical Physics, 2020

From bacterial colonies and growing tumors to forest fires and spreading of rumors, phenomena of spreading and growth can be seen everywhere. While studying models of these processes, it is natural to ask about the spatial extent of the growing cluster at any given time – during a disease outbreak, in what regions should you focus your immunization programs? Or given that a rumor has been started by a specific person, who are the people to whom the rumors would have reached? In this work, we provide answers to these questions in the context of the Eden model, which is one of the simplest models of growing clusters, originally developed to investigate the growth of biological cell colonies.

Extreme Events in Stochastic Transport on Networks

Published in Chaos, 2020

Extreme events often tend to be associated with natural disasters such as the floods, droughts and earthquakes. However, more generally, any event whose magnitude displays pronounced deviation from its typical average value can be regarded as an extreme event. This definition includes events ranging from traffic congestion to powerblack-outs. In particular, many of these extreme events take place on the topology of a network. Hence, it is of interest to study how the network structure affects extreme event properties, and if these networks, as a whole unit, can survive the onslaught of extreme events taking place on them. Using the paradigm of random walks on complex networks, in this work, we perform a detailed analytical study of extreme events that occur on the edges of networks, which complements previous works on extreme events on nodes, while simultaneously providing several fresh insights.

TASEP Speed Process: An Effective Medium Approach

Published in Journal of Statistical Mechanics, 2020

Advantage begets further advantage - this effect, often called the Matthew effect, is observed in various forms in day-to-day life, most commonly in social and economic aspects. But can such an effect be seen in systems where the evolution is completely memory-less? In this work, we study the TASEP Speed Process, in which the dynamics of a special particle at late times is heavily determined by its dynamics at early times. We provide a simple description of this phenomenon using an effective medium approximation and demonstrate its applicability in other relevant settings. A simple presentation of our key findings is given in this poster which was presented at the Indian Statistical Physics Community Meeting 2020, held at the International Centre for Theoretical Sciences, Bangalore.

Distinct Nodes Visited by Random Walkers on Scale-Free Networks

Published in Physica A, 2019

How fast can a group of randomly walking drunkards starting from one node of a scale-free network explore the rest of the network? We look to answer this question in our work and find that, unlike regular lattices, the number of sites of a scale-free network not visited by any of the random walkers decays as a stretched exponential. Furthermore, we obtain scaling relations that allow us to map the problem with multiple random walkers to that of the analytically tractable single walker problem. A simple presentation of our key findings is provided in this poster which was presented in the WE-Heraeus Seminar “Search and Problem Solving by Random Walks: Drunkards Vs. Quantum Computers” which took place in the Physikzentrum at Bad Honnef near Bonn (Germany) from May 28 to June 1, 2018.