Gareth Alexander

I am an Associate Professor in Physics and the MathSys CDT working in theoretical soft matter physics. My main interests at present are in active matter and applications of geometry and topology to the understanding of soft materials. Before moving to Warwick I was a post-doc at UPenn working with Randy Kamien. And before that I was a DPhil student in Oxford with Julia Yeomans.

Teaching

In 2024/2025 I will lecture the following courses:

• PX3A7 Statistical Physics (lecture notes )

Recently, I have also taught:

• PX436 General Relativity (lecture notes )
• PX276 Methods of Mathematical Physics (lecture notes )

Research

My research currently focuses on active matter, chiral mechanics, and geometric and topological properties of liquid crystals and soft matter. I have previously worked on knotted fields, low Reynolds number hydrodynamics, and soap films.

I am currently working with Enej Caf (Ljubljana/Warwick) and Miha Ravnik (Ljubljana) on three-dimensional active liquid crystals; with Cameron Smith and Tim Saunders (WMS) on development of muscle tissue in zebrafish; with SJ Kole (Chicago), Ananyo Maitra (CNRS, Cergy) and Sriram Ramaswamy (IISc) on chiral mechanics and odd elasticity; and with Sami Al-Izzi (UNSW) on active surfaces.

If you are interested in working with me, please feel free to contact me by email. For PhD applications, please also see the departmental pages.

Selected publications

• "Screw symmetry, chiral mechanics, and odd instability in active cholesterics", Phys. Rev. E 112, 055424 (2025).

with SJ Kole, Ananyo Maitra, and Sriram Ramaswamy

• "Chirality and odd mechanics in active columnar phases", PNAS Nexus 3(10), pgae398 (2024).

with SJ Kole, Ananyo Maitra, and Sriram Ramaswamy

• "Escape into the third dimension in cholesteric liquid crystals", New J. Phys. 26, 063027 (2024).

with Joseph Pollard

• "Topology in soft and biological matter", Phys. Rep. 1075, 1-137 (2024).

with Luca Tubiana et al.

• "Three-Dimensional Spontaneous Flow Transition in a Homeotropic Active Nematic", Commun. Phys. 7, 127 (2024).

with Vincenzo J Pratley, Enej Caf, and Miha Ravnik

• "A Twist on Active Membranes: Odd Mechanics, Spontaneous Flows and Shape Instabilities", Phys. Rev. Research 5, 043227 (2023).

with Sami Al-Izzi

• "Colloids in two-dimensional active nematics: conformal cogs and controllable spontaneous rotation", New J. Phys. 25, 123006 (2023).

with Alexander JH Houston

• "Entanglements and Whitehead Products: Generalizing Kleman's Construction to Higher-Dimensional Defects", Liq. Cryst. Rev. 10, 91 (2022).

with Randall D Kamien

• "Layered Chiral Active Matter: Beyond Odd Elasticity", Phys. Rev. Lett. 126, 248001 (2021).

with SJ Kole, Sriram Ramaswamy, and Ananyo Maitra

• "Geometry of Bend: Singular Lines and Defects in Twist-Bend Nematics", Phys. Rev. Lett. 125, 047801 (2020).

with Jack Binysh and Joseph Pollard

• "A Björling representation for Jacobi fields on minimal surfaces and soap film instabilities", Proc. R. Soc. A 476, 20190903 (2020).

with Thomas Machon

• "Three-Dimensional Active Defect Loops", Phys. Rev. Lett. 124, 088001 (2020).

with Jack Binysh, Žiga Kos, Simon Čopar, and Miha Ravnik

• "Knot your regular crystal of atoms", Science 365, 1377 (2019).

This article can be accessed free of charge via the following links: [summary] [reprint] [full text]

• "Point Defects, Topological Chirality, and Singularity Theory in Cholesteric Liquid-Crystal Droplets", Phys. Rev. X 9, 021004 (2019).

with Joseph Pollard, Gregor Posnjak, Simon Čopar, and Igor Muševič

• "Maxwell's theory of solid angle and the construction of knotted fields", J. Phys. A: Math. Theor. 51, 385202 (2018).

with Jack Binysh

• "Vortex formation and dynamics of defects in active nematic shells", New J. Phys. 19, 103043 (2017).

with Diana Khoromskaia

• "Exact solutions for hydrodynamic interactions of two squirming spheres", J. Fluid Mech. 813, 618-646 (2017).

with Dario Papavassiliou

• "Instabilities and Solitons in Minimal Strips", Phys. Rev. Lett. 117, 017801 (2016).

with Thomas Machon, Raymond E. Goldstein, and Adriana I. Pesci

• "Global Defect Topology in Nematic Liquid Crystals", Proc. R. Soc. A 472, 20160265 (2016).

with Thomas Machon

• "Umbilic Lines in Orientational Order", Phys. Rev. X 6, 011033 (2016).

with Thomas Machon

 

Write to:

Centre for Complexity Science, Zeeman Building, University of Warwick, Coventry CV4 7AL, UK

 

Contact Details:

Office: D1.09 Zeeman Building
Telephone:
44 (0)2476 150210
Fax:

E-Mail:
G.P.Alexander@warwick.ac.uk