Physics Department Colloquium

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.

Synchronization—the spontaneous emergence of phase coherence among interacting oscillators—is a ubiquitous phenomenon in classical systems, from pendulum clocks to biological rhythms. In quantum systems, however, coherence is fragile, and environmental noise is usually viewed as its primary adversary. This colloquium explores a counterintuitive regime in which noise itself becomes a resource, driving rather than destroying coherent behavior.

Earth's clouds are critical for weather and climate. Cloud formation in earth and other planetary atmospheres is a deceptively simple physical process of condensation. And yet clouds are very challenging to understand and predict due to the interplay of clouds with their environment. Cloud physics spans 12 orders of magnitude in space from the micro-scale of cloud drops to the planetary scale of the general circulation and a similar order of magnitude in time from fractions of a second of cloud drop collisions to centennial climate time scales.