Extended Poisson-Kac Theory: A Unifying Framework for Stochastic Processes with Finite Propagation Velocity

Stochastic processes are a cornerstone of physics and engineering, particularly for modelling transport phenomena in the natural and social sciences, including the random movements of cells, bacteria, and viruses, climate fluctuations or the dynamics of financial markets. Such models typically capture the essential statistical character of dynamics on long timescales, yet Read more

Measurement-induced quantum walks

Quantum systems generally lack precise trajectories. Hence, the notion of a quantum random walk is somewhat problematic. One way to make the idea precise is to consider quantum evolution which is repeatedly interrupted by position measurements, each of which localises the system to a particular state. Read more

Afterslip Moment Scaling and Variability from a Global Compilation of Estimates

Aseismic afterslip is the gentle slipping or sliding of a fault over several months or years following an earthquake. The process involves aseismic shear and post-seismic readjustment occurring on and close to the fault planes of the parent earthquake, quite distinct from generally deeper and more distributed viscoelastic relaxation. Read more

Forecasting new diseases in low-data settings using transfer learning

Epidemic models fall into two broad categories – those which fit an epidemic curve to past data in order to make predictions about the future, and mechanistic models which simulate more general scenarios based on specific underlying assumptions on factors such as varying contact rates Read more

Emerging locality of network influence

Complex systems of many components – the internet, economies, cells, ecosystems, and so on – depend on the rich web of interactions among many parts. In analysing such systems, however, it is natural that scientists often want to rank the components in terms Read more

Naive Probabilism and Covid-19

In the early weeks of the 2020 U.S. Covid-19 outbreak, guidance from the scientific establishment and government agencies included a number of dubious claims – masks don’t work, there’s no evidence of human-to-human transmission, and the risk to the public is low. Read more

The Global Inequality Boomerang

Since the late 1980s, global income inequality has fallen by most common definitions, largely due to the changing economic relationships between nations, including the rapid rise of China and India as economic centres. Read more

Stability of heteroclinic cycles in rings of coupled oscillators

Complex networks of interconnected physical systems arise in many areas of mathematics, science and engineering. Many such systems exhibit heteroclinic cycles – dynamical trajectories that show a roughly periodic behaviour, with non-convergent time averages. Read more

Learning a weather dictionary of atmospheric patterns using Latent Dirichlet Allocation

The mid-latitude atmospheric circulation is challenging to describe due to the turbulent and chaotic nature of the underlying flow, driven by the unstable dynamics of the jet stream. In general, the phase space of such turbulent geophysical flows appears to be large. Even so, previous work using dimensionality reduction methods has shown Read more

Metrics and Mechanisms: Measuring the Unmeasurable in the Science of Science

How does science work? What are its core mechanisms? In recent decades, research has increasingly explored such questions using a variety of quantitative metrics which can be easily calculated from publications. But some of these can be deceiving. Read more