Physics Department Colloquium

The interplay between spin and charge in chiral materials — ranging from simple organic molecules to complex hybrid semiconductors — has emerged as one of the more intriguing open scientific problems. Chirality is fundamentally a symmetry question — an object is chiral if it cannot be superimposed on its mirror image — and chirality-induced spin selectivity (CISS), whereby chiral materials preferentially transmit electrons of a particular spin orientation, is a striking consequence of this broken symmetry.

Condensed matter physics aims to explore and underst

The first year of a Ph.D.

As educators, we would like to prepare our students for 21st century physics careers. Overall, to ensure all students will become successful scientists, physics departments need to be able to provide evidence to make sure that we are reaching these goals. The field of Physics Education Research has made major contributions to various educational practices and materials to reform instruction in order to recruit and retain more students.

For the last quarter century, experiments at Brookha

Active systems are driven out of equilibrium by exch

Spin glasses are canonical examples of complex matter and form a basis for describing artificial neural networks.  Repeatable control over microscopic degrees of freedom might open a new window into their structure and dynamics.  I will present how we achieved this at the atomic level using a quantum-optical system comprised of ultracold gases of atoms coupled via photons resonating within multimode cavities.

Abstract: Effective field theories (EFTs) form the basis of our most successful theories of matter, both in particle physics and in condensed matter physics. But the structure of EFTs poses a challenge to many standard philosophical accounts of theory structure and content. In particular, the inability to cast EFTs in terms of exact mathematical objects defined at all scales suggests that philosophical accounts of theory interpretation ought to be modified to deal with approximate, scale-relative ontologies.

Abstract: Low energy collisions between molecules in the atmosphere lead to about 50% of the particles that act as the seeds for cloud droplets. Many of these molecules, and many of the other particles, are the result of human activity. Therefore cloud droplet concentrations have increased over the industrial period. The increase has led to a poorly quantified cooling effect on Earth that has offset perhaps a third of historical warming from greenhouse gases. The CLOUD experiment at CERN is a laboratory facility for the study of atmospheric particle formation.

Abstract: The mineralogy of our planet is a fingerprint of history—a durable archive of the physical and chemical conditions that have evolved over 4.5 billion years. Minerals record temperatures and pressures, redox states and fluid compositions, preserving evidence that spans the earliest violent collisions of solar-system formation to human activities that occurred only yesterday. Yet Earth’s mineral story reaches far deeper in time, extending back to the very origins of the elements themselves.