Bridging the quantum-classical divide

In this theme we will seek to better understand the quantum-classical (QC) interface and the irreversible behaviour that originates there. We will blend geometric mechanics and stochastic methods with physical intuition to provide new solutions to questions in QC dynamics and the origin of decoherence and irreversibility, along with its thermodynamic direction of time.

Specifically, we will combine our new developments on the mathematics of Koopman wave functions with our constructor theory to provide an entirely new framework for the description of hybrid QC systems.

Research aims

Our research will focus on three strands of investigation:

  • Developing a reversible theory of QC coupling to overcome known consistency issues
  • Considering entropy sources for describing irreversibility
  • Investigating the emergence of classicality in dynamic models.


The development of QC theories and the inclusion of environmental entropy sources will require us to revisit several concepts which have long been discussed but which have lacked a mathematical perspective to enable realistic quantitative predictions. This aspect will be particularly relevant for the development of new methods in molecular dynamics.


Meet the team


Jim Al-Khalili profile image

Professor Jim Al-Khalili

University of Surrey

Dorje C Brody profile image

Professor Dorje Brody

University of Surrey

Paul Davies

Professor Paul Davies

Arizona State University

Chiara Marletto

Chiara Marletto

University of Oxford

Andrea Rocco profile image

Dr Andrea Rocco

University of Surrey