Debra Bernhardt (née Searles) is an Australian theoretical chemist. She is best known for her contributions towards understanding the fluctuation theorem. This theorem shows the second law of thermodynamics and the zeroth law of thermodynamics can be derived mathematically rather than postulated as laws of nature.
Bernhardt has previously worked as an associate professor in the Faculty of Science at Griffith University. During her time at Griffith University, she became the founding director of the Queensland Micro- and Nanotechnology Centre. She received her PhD from the University of Newscastle for her work on quantum chemistry. In 2012, Bernhardt joined the University of Queensland as a professor in a joint appointment between the School of Chemistry and Molecular Biosciences and the Australian Institute of Bioengineering and Nanotechnology.
In 2019 Bernhardt was elected to a Fellowship of the Australian Academy of Science. She is also a Fellow of the Royal Australian Chemical Institute. In the past, Bernhardt has also held research positions at the University of Basel in Switzerland and Australian National University.
Bernhardt's research interests are in the study of liquids under equilibrium and nonequilibrium conditions, development of the theory of nonequilibrium fluids and use of simulations to assist in understanding experimental results. Current research projects include: the study of nonequilibrium liquids via statistical mechanics; nonequilibrium molecular dynamics; dynamical systems theory; chaos theory; the fluctuation theorem; the study of fluids in confined spaces; the development of algorithms for molecular dynamics simulations; and the calculation of liquid properties. Bernhardt has made significant contributions to theoretical computational chemistry, including combining quantum chemistry and molecular simulation, as well as the calculation of transport properties of materials.