Prof Claudio Castelnovo
Professor of Theoretical Physics
Fellow of Trinity College
Office: 528 Mott Bld
Phone: +44(0)1223 3 37433
Email: cc726 @ cam.ac.uk
Personal web site
TCM Group, Cavendish Laboratory
19 JJ Thomson Avenue,
Cambridge, CB3 0HE UK.
I am generally interested in emergent and out of equilibrium phenomena in many body systems, both in classical statistical mechanics as well as in collective quantum phenomena. My research topics include:
- effects of hard constraints in classical and quantum systems (dimer, vertex, and colouring models)
- kinematic constraints, out of equilibrium phenomena, freezing and glassiness
- frustrated magnetism, classical and quantum spin liquids
- entanglement, topological order, quantum information and quantum computing
- photoinduced phases of matter
In Plain English
Strongly correlated many body physics is the study of large ensembles of `particles' (whichever the relevant elementary constituents of the system may be) interacting with one another. Strong interactions give rise to collective behaviours that trascend the nature of the microscopic constituents. For example, the different phases and phase transitions of water, magnetism, superconductivity and superfluidity all result from strong correlations in systems of electrons and ions.
This phenomenon is generally dubbed emergence: the ability to exhibit collective behaviour that would have been virtually impossible to predict or understand from solely focusing on the nature of the elementary constituents of the system. Late examples of emergence include new types of order that cannot be detected at local level (topological order) and emergent particles that are in apparent contradiction of what know and observe in the universe, including charges that are a fraction of the charge of an electron and magnetic monopoles.
Emergence is not limited to properties of the system in thermodynamic equilibrium. Strongly correlated systems also exhibit a rich and unusual phenomenology in their out of equilibrium behaviour. This takes place when a sufficiently rapid change is introduced (e.g., a change in temperature) that the system is unable to adapt to it instantatenously. A transient regime follows, in which the system responds to the change and gradually relaxed to the new thermodynamic equilibrium state. Emergent phenomena out of equilibrium include well known examples such as turbulence and glassiness, namely the appearance of unusually long relaxation time scales.
Although the condensed matter physics community has been working on emergent and out of equilibrium phenomena for several decades already, this is still very much a lively, interesting and exciting area of research to date. Scientists are both striving to improve our fundamental understanding as well as predicting and understanding new related phenomena for potential technological application.
- Rod motifs in neutron scattering in spin ice. Physical Review B (Rapid) 99 121102 (2019)
- Role of defects in determining the magnetic ground state of ytterbium titanate. Nature Communications 10 637 (2019)
- Emergent order in the kagome Ising magnet Dy$_3$Mg$_2$Sb$_3$O$_14$. Nature Communications 7 13842 (2016)
- Emergent Coulombic criticality and Kibble-Zurek scaling in a topological magnet. Physical Review B 92 075142 (2015)
- Vacancy defects and monopole dynamics in oxygen-deficient pyrochlores. Nature Materials 13 488 (2014)
- Tunable nonequilibrium dynamics of field quenches in spin ice. P. Natl. Acad. Sci. USA 111 640 (2014) arXiv:1309.4676v2
- Spin ice, fractionalization, and topological order. Annual Review of Condensed Matter Physics 3 35 (2012) arXiv:1112.3793
- Dirac strings and magnetic monopoles in the spin ice Dy2Ti2O7. Science 1326 411 (2009) arXiv:1011.1174
- Magnetic monopoles in spin ice Dy2Ti2O7. Nature 451 42 (2008) arXiv:0710.5515