Radiative Cascade in Rydberg Atoms

This talk is an introduction to the physics of Rydberg atoms. The two complementary flavors of Rydberg atoms, high and low angular momentum states, have contrasting properties as they relate to the correspondence principle that bridges classical behavior to quantum mechanics. Dynamic symmetries allow a unified point of view to investigate this correspondence. Highly excited atoms dissipate their energy in different ways depending on their initial angular momentum: low angular momentum states make transitions in large energy increments, quickly approaching the ground state, while high angular momentum states make small steps, slowly spiraling towards lower states.

Mark Williamsen, Quantum Design, Inc

Applications of AC Bridges in Cryogenic Measurements

AC (alternating current) bridges have proven to be useful in making precise measurements at low temperature, including thermometry as well as length change with respect to either thermal expansion (dilatometry) or applied magnetic field (magnetostriction). Techniques now in use allow one leg of the bridge to be placed at the cryogenic sample site while the other legs remain at room temperature, with the intervening temperature gradient being imposed along a length of coaxial cable.

Dr. Morgan Lynch, Technion – Israel Institute of Technology

A Brief History of Quantum Field Theory in Curved Spacetime

The incorporation of classical general relativity into the framework of quantum field theory yielded a rather surprising result -- thermodynamic particle production. In short, for fundamental deformations in the structure of spacetime, quantum mechanics necessitates the creation of thermalized particles from the vacuum. One such phenomenon, known as the Unruh effect, causes empty space to effervesce a thermal bath of particles when viewed by an observer undergoing uniformly accelerated motion.

In this presentation, we will review the timeline of conceptual discoveries which led to broad classes of these intriguing thermodynamic phenomena. Beginning with the original discovery of particles created by the expansion of the universe, we will cover a brief history of quantum field theory in curved spacetime, culminating in the first experimental observation of the Unruh effect, and other aspects of acceleration-induced thermality, in high energy channeling radiation.