
James P. Eisenstein
Wolf Prize Laureate in Physics 2025

James P. Eisenstein
Affiliation at the time of the award:
Caltech, USA
Award citation:
“For advancing our understanding of the surprising properties of two-dimensional electron systems in strong magnetic fields”.
Prize share:
James P. Eisenstein
Jainendra K. Jain
Mordehai Heiblum
James P. Eisenstein (1952, USA) earned his AB degree from Oberlin College in 1974 and completed a Ph.D. in physics at the University of California, Berkeley, in 1980. After serving as an assistant professor at Williams College, he joined Bell Laboratories in 1983 as a member of the technical staff. In 1996, he accepted a faculty position at the California Institute of Technology (Caltech) and became the Frank J. Roshek Professor of Physics and Applied Physics in 2005. He retired as professor emeritus in 2018 and concluded his experimental research in 2021. Eisenstein has contributed to several National Research Council committees, including the Solid State Sciences Committee and the Board on Physics and Astronomy. He also served as associate editor for the Annual Review of Condensed Matter Physics from 2014 to 2017.
The three awardees have profoundly transformed our understanding of the fractional quantum Hall effect, (a Nobel prize-winning phenomenon) in which a thin layer of electrons in a magnetic field behaves as if the electrical current is carried by particles charged with a fraction of the electron charge.
A powerful and intuitively appealing way to understand these particles was developed by Dr. Jain, who introduced the concept of a composite fermion: a particle formed by binding an electron to a magnetic flux tube. The idea that large numbers of strongly interacting electrons behave as weakly interacting composite particles explains the intricate sequence of fractional quantum Hall states observed in the laboratory, now known as the Jain states. The composite fermion theory has provided quantitatively precise agreement with numerical studies, and it has predicted and explained experiments that find behavior reminiscent of a superconductor at special values (filling fraction 5/2) of the electron density.
Dr. Heiblum pioneered the exploration of these exotic particles in the laboratory. By developing ultra-high-purity materials and electron interferometry techniques, Heiblum’s group could provide concrete evidence for the fractional charge and verify fundamental predictions, including the anomalous statistics (intermediate between that of fermions and bosons). A milestone experiment was the observation of half-integer quantized thermal conductance at filling fraction 5/2, confirming the prediction that the corresponding composite fermions are Majorana fermions, and with potential implications for quantum computation.
Dr. Eisenstein co-discovered the fractional quantum Hall state at filling factor 5/2 and went on to explore exotic phases of two-dimensional electron systems. This includes an anisotropic state where the resistance probed along one direction is much larger than the resistance along the perpendicular direction, reminiscent of a liquid crystal. Eisenstein’s development of methods to separately contact individual electron layers enabled the study of the correlated motion of electron-hole pairs in the two layers, with the breakthrough observation of their Bose-Einstein condensation.
The award of the 2025 Wolf prize to these three physicists honors their extraordinary contributions to the exploration of quantum matter, with far-reaching impact on emerging quantum technologies.
