Imperial College London


Faculty of Natural SciencesDepartment of Physics

Professor of Theoretical Physics



+44 (0)20 7594 7574k.christensen Website




Mrs Carolyn Dale +44 (0)20 7594 7579




1226, Center for Complexity ScienceElectrical EngineeringSouth Kensington Campus





I work in the fields statistical mechanics  and complexity with an emphasis on far from equilibrium phenomena. The science of complexity is highly interdisciplinary and often deals with dynamical systems composed of many interacting units, for example organisms in biology, heart mucle cells in the myocardium, grains in granular media, network of agents in economics etc. Methods from statistical mechanics are emplyed to gain insight into the behaviour of such systems.

The overall objective of the science of complexity is to address why Nature is complex, not simple as the laws of physics seem to imply. How, for example, can scale invariance and organisation emerge from simple underlying rules associated with the individual units? In this sense, complexity refers to the emergent behaviour that arises from the repeated application of simple rules in systems with many degrees of freedom.

Keywords: Statistical mechanics, complexity, non-equilibrium systems, emergent properties, scale invariance, fractals, self-organised criticality, granular systems, ricepiles, stick-slip behaviour, spring-block models, relaxation processes, avalanches, earthquakes, rain, evolution, and atrial fibrillation.


Prof. Nicholas S. Peters, Faculty of Medicine, Dept. of Cardiology, Imperial College London, Modelling atrial fibrillarion: We have developed a simple (yet faithful) model for the propagation of electrical signals in the heart muscle (myocardium) that displays a phase transion from normal heart rhythm to atrial fibbrilation as a function of increasing defect density in the myocardium. Potentially, the model would allow us to investigate how to otimise ablative treatment of atrial fibrillation., 2011

D Edwards, Weston professor of neonatal medicine, Institute of clinical sciences, Imperial College London, Neuroscience, brain dynamics, brain fMRI, 2010

D Chialvo, Professor, David Geffen School of Medicine, University of California, Los Angeles (UCLA), Neuroscience, brain dynamics, brain fMRI, 2008

F Turkheimer, Center for Neuroscience, Dept. of Medicine, Imperial College London, Neuroscience, brain dynamics, brain fMRI, 2008

P Vuust, Professor, Royal Academy of Music & University of Aarhus, Neuroscience of musical creativity, EEG, 2008

J Bhattacharya, Dept. of Psychology, Goldsmith, University of London, Neuroscience of musical creativity, EEG, 2008

T. Dahl, roboticist, Dept. of computing, University of Wales, Newport, Emergent behaviours in multi-robot systems. Viable social systems., 2006 - 2010

A Espinosa, computer and systems engineer, Business school, Hull University, Viable social systems. Management systems., 2006

N Franks, Professor of animal behaviour and ecology, School of biological sciences, University of Bristol, Self-regulatory systems. Ant colonies as complex systems., 2006

AB Sendova-Franks, Reader in biometry and animal behaviour, Dept. of Engineering & Mathematics, University of the West of England, Self-regulary social systems. Ant colonies as complex systems., 2006

HJ Jensen, Professor of Mathematical Physics, Dept. of Mathematics, Imperial College London, Self-organised criticality, biological evolution, dynamical systems, complexity and network science, brain dynamics, musical creativity, 1988

Research Student Supervision

Collobiano,SAD, Tangled Nature: A model of ecological evolution

Expert,P, An Odyssey with complexity and network science: From the brain to social systems

Farid,N, On the dynamics and topology of networks

Moloney,NR, Numerical investigations into order parameter fluctuations

Pancaldi,V, Coarse graining equations for flow in porous media: A Haar wavelets and renormalization approach

Peters,DOB, Approaches to criticality: Rainfall and other relaxation processes

Rahman,S, Neuroscience of musical creativity

Stapleton,M, Self-organised criticality and non-equilibrium statistical mechanics

Zachariou,N, Socio-economic systems and sustainability