Announcements

A special congratulation to Paul Corkum, University of Ottawa, who has won the American Physical Society's 2025 APS Medal for exceptional achievement in research, in the fields of plasma physics, strong-field spectrosocpy, electron scattering, as well as for pioneering the use of attosecond laser pulses.  

Paul was a graduate student in the Department of Physics in the group of Prof. McLennan and obtained his PhD from Lehigh University in 1972. The APS Medal is a new entry in a long list of recognitions that include the Wolf Prize in physics.

See also Paul Corkum’s journey from experiment to theory and back again, at the American Physical Society.

Photon absorption in some organic molecular semiconductor crystals can create a photoexcited state that spontaneously splits into a pair of mobile, spin-entangled triplet excitons, where each quasiparticle has an electronic spin of 1 but the pair has a total spin of zero. The triplet excitons (spin-1 excitons) in this system are a condensed matter equivalent of the entangled photons created by parametric down conversion in nonlinear optical crystals.

New work by Biaggio's group has introduced transport induced dephasing as a key process that can suppress the quantum beats normally associated to entanglement when triplet excitons can localize on inequivalent sites in the crystal lattice, leading to global decoherence in a population of entangled triplet pairs..

 About global decoherence, entanglement, and dephasing

 Link to publication

Lehigh University's Department of Physics invites applications to our graduate program. Students interesting in obtaining a MS or PhD degree in physics please visit our dedicated site, physisgraduate.lehigh.edu. There you will find information on the program, possible PhD research topics, deadlines, application procedure, and on-line virtual information sessions that we provide to everyone interested in the program.

https://physicsgraduate.lehigh.edu

S. Cremonini, M. Cvetič, C. N. Pope, and A. Saha

Phys. Rev. D 106, 086007 – Published 13 October 2022

Motivated by recent studies of long-range forces between identical black holes, we extend these considerations by investigating the forces between two nonidentical black holes. We focus on classes of theories where charged black holes can have extremal limits that are not BPS. These theories, which live in arbitrary spacetime dimension, comprise gravity coupled to N 2-form field strengths and (N − 1) scalar fields. In the solutions we consider, each field strength carries an electric charge. The black hole solutions are governed by the SL (N + 1, R) Toda equations. In four dimensions, the black hole solutions in the SL(3, R) example are equivalent to the “Kaluza-Klein dyons.” We find that any pair of such extremal black holes that are not identical (up to overall scaling) will repel one another. We also show that there can exist pairs of non-extremal, nonidentical black holes which obey a zero-force condition. Finally, we find indications of similar results in the higher examples, such as SL(4, R).

Ding Zhang and Ariel Sommer

Physical Review Research 4, 023231 (2022) 

The interface between a strongly polarized normal gas and a weakly polarized superfluid at finite temperature presents a model for understanding transport at normal-superfluid and normal-superconductor interfaces. 

Image