Michael Elmhirst Cates (born 5 May 1961) is a British physicist.
He is the 19th Lucasian Professor of Mathematics at the University of Cambridge and has held this position since 1 July 2015.
He was previously Professor of Natural Philosophy at the University of Edinburgh, and has held a Royal Society Research Professorship since 2007.His work focuses on the theory of soft matter, such as polymers, colloids, gels, liquid crystals, and granular material.
A recurring goal of his research is to create a mathematical model that predicts the stress in a flowing material as a functional of the flow history of that material.
Such a mathematical model is called a constitutive equation.
He has worked on theories of active matter, particularly dense suspensions of self-propelled particles which can include motile bacteria.
His interests also include fundamental field theories of active systems in which time-reversal symmetry (T-symmetry, and more generally, CPT symmetry) is absent.
Such theories are characterised by nonzero steady-state Entropy production.
At Edinburgh, Cates was the Principal Investigator of an EPSRC Programme Grant, awarded in 2011, entitled Design Principles for New Soft Materials.
On his departure for Cambridge, Cait MacPhee took over as Principal Investigator.