David O'Regan

David D. O'Regan is an Irish physicist and professor in physics at Trinity College Dublin, where he leads the Quantum Theory of Materials Research Group.^[1] He is also a member of the CRANN institute, a large centre for nanoscience research at Trinity.^[2]

O’Regan received his B.Sc. Joint Honours in Mathematics and Physics from University College Cork. He completed his PhD at Pembroke College, University of Cambridge, working in the Theory of Condensed Matter Group of the Cavendish Laboratory under the supervision of Michael C. Payne.^[3][4]

O’Regan conducted postdoctoral research at Cambridge and then at École Polytechnique Fédérale de Lausanne (EPFL). He joined Trinity College Dublin in 2014 and was elected as a Fellow of the College in 2022.^[5]

His research focuses on developing and applying efficient methods in density-functional theory (DFT), including varieties of constrained DFT,^[6] DFT+U^[7] and TDDFT, in either conventional and linear-scaling implementations. He has contributed to the foundations of the DFT+U approach, such as with frameworks for Hubbard U and Hund J calculations^[8] and with the BLOR class of double-counting-free functionals.^[9] O’Regan and colleagues have generalized the DFT flat-plane condition to high-energy magnetization states.^[10][11]