## Summary

I am currently a member of the Theoretical Physics Group and, in addition, a member of the cross-disciplinary Centre for Complexity Science, My current research follows two broad, but very different, paths that reflect this duality: quantum field theory and complex spatial networks.

For the former I use path integral techniques. In particular I am exploiting parallels between the soundcone metrics of Fermi gas condensates and lightcone metrics of astrophysics and relativity in a long-standing collaboration with the National Dong Hwa University in Taiwan and APC, U. of Paris 7. I also have a collaboration with the Technical University of Prague on the relationship between classical and quantum physics from the viewpoint of Koopman and von Neumann.

My work on complexity is largely in collaboration with Tim Evans of the Theoretical Physics Group and the Centre for Complexity Science and addresses applications and issues in modelling spatial networks, particularly archaeological networks. In this I am part of a loose collaboration incorporating mathematicians, computer scientists and archaeologists (in particular U. of Toronto). Such network modelling is strongly influenced by that used in contemporary urban planning for transport, commuting and city development. Like astrophysics, archaeology is intrinsically Bayesian although data is very poor. I have been particularly concerned with the limitations of modelling; sensitivity, resilience, the role of contingency, etc. Computationally, the methods are not unlike those used in simulations of lattice field theory (e.g. Metropolis).

Whereas quantum field theory papers can be found easily on the arXiv, in archaeology our/my papers infrequently in journals (e.g. Antiquity) but usually in monographs (sometimes published years after the event). Tim Evans' web page gives access to some of them.

## Publications

### Journals

Rivers RJ, Steer DA, Lin C-Y, et al. , 2018, When are two fermions a simple boson? New Gross-Pitaevskii actions for cold Fermi condensates, *Annals of Physics*, Vol:396, ISSN:0003-4916, Pages:495-516

Hsiang J-T, Lee D-S, Lin C-Y, et al. , 2015, Quantum sound-cone fluctuations in cold Fermi gases: Phonon propagation, *Physical Review A*, Vol:91, ISSN:1050-2947

Evans TS, Rivers RJ, 2014, New approaches to Archaic Greek Settlement Structure, *Les Nouvelles De L'archéologie*, Vol:135, ISSN:0242-7702, Pages:21-27

Hsiang J-T, Lin C-Y, Lee D-S, et al. , 2013, The role of causality in tunable Fermi gas condensates, *Journal of Physics-condensed Matter*, Vol:25, ISSN:0953-8984

### Software

Rivers R, Knitter D, Bilger M, et al. , 2018, *CRC1266-A2/moin: Release after Moin Summer School*, v.1.01