Nonstationary Background Seismicity Rate and Evolution of Stress Changes in the Changning Salt Mining and Shale-Gas Hydraulic Fracturing Region, Sichuan Basin, China

Many earthquakes have been induced by human activities, including wastewater disposal, geothermal production, gas injection and hydraulic fracturing (HF). Read more

Non-Equilibrium Dynamics and Weakly Broken Integrability

Scientists still lack a fundamental understanding of how and when complex many-body systems out of equilibrium will relax back to thermal equilibrium. Empirically, many systems do relax readily, justifying many of the core approximations of thermodynamics. Read more

Giant leaps and long excursions: fluctuation mechanisms in systems with long-range memory

Many random processes lack memory – that is, the probability distribution for change over any time interval depends on the present state of the process but remains independent of how it behaved previously. Read more

On the Computation of the Extremal Index for Time Series

Many insights have recently emerged from applications of extreme value theory to the study of time series generated by dynamical systems. Read more

What are we weighting for? A mechanistic model for probability weighting

It’s a common belief in areas such as psychology, economics or finance that people suffer from cognitive biases — systematic deviations from correct or rational behaviour when they make decisions. Read more

Asymptotic estimates of SARS-CoV-2 infection counts and their sensitivity to stochastic perturbation

Since the outbreak of the coronavirus, modellers from around the world have scrambled to predict the course of its spread, projecting forward from data on past infections and deaths in any region. Such estimates help public health officials and governments to judge the possible risks they face, and, on their basis, many nations have imposed restrictive social confinement measures. Read more

The effect of social balance on social fragmentation

Nations and communities typically function as relatively coherent groups, yet also occasionally fall apart or fragment into highly polarised sub-groups. Read more

Phase transitions in atypical systems induced by a condensation transition on graphs

Random graphs can undergo structural phase transitions as a function of their model parameters. For example, in the well-known percolation transition, a network-spanning cluster of linked nodes abruptly appears at a critical value of the probability, c, for a link to exist between any pair of nodes. Read more

A percolation model for the emergence of the Bitcoin Lightning Network

The distributed ledger system known as blockchain has triggered a revolution in the payments industry, and is the technological infrastructure underlying cryptocurrencies such as Bitcoin. Even so, the blockchain concept itself faces some limitations which may hinder its future growth and adoption. Read more

Approximate Uncertain Programs

Uncertain programs are optimization problems involving uncertainties in constraints or objectives. In the past few decades, such programs have been applied in areas from economics and management to automotive control and machine learning. Read more