Webinars

Transient self-assembled structures occur frequently in complex biological systems and are involved in regulating processes such as the transport, motility, and proliferation of cells. From a coarse-grained perspective, these materials can perform these complex tasks because they operate under nonequilibrium conditions. Originally aired July 2022.

In this webinar we explore the consequences of three demons that checker the past of thermodynamics. The first demon—Loschmidt's demon—threatens our understanding of the source of time-asymmetry. If we had the power to reverse the momenta of molecules in a gas, would we see the past unwind before our eyes? If so, why don't we ever see this? Originally aired June 2022.

The elementary CuO2 plane sustaining cuprate high temperature superconductivity occurs typically at the base of a periodic array of edge-sharing CuO5 pyramids. Virtual transitions of electrons between adjacent planar Cu and O atoms, occurring at a rate t/ℏ and across the charge-transfer energy gap E, generate ‘superexchange’ spin-spin interactions…Watch the video to learn more! Originally aired May 2022.

Jay Pasachoff is the Field Memorial Professor of Astronomy at Williams College and Chair of the International Astronomical Union’s Working Group on Solar Eclipses. A veteran of 36 total solar eclipses and 75 solar eclipses of all types, he will discuss solar eclipse studies as of 2022 and beyond. Originally aired May 2022.

In this webinar we will discuss how atmospheric drag causes satellites to reenter, and look at historical data on where this occurs. We will compare it to the structure and density profile of the Earth’s atmosphere and discuss where the forces of gravity become more important than atmospheric forces, and how this varies with time and place. We will also review some of the historical ideas on the subject. Originally aired April 2022.

Photons are excellent carriers of quantum information over long distances and can be reliably processed in advanced photonic integrated circuits. One fundamental challenge has been that they are complex to generate, i.e. single-photon sources tend to be inherently inefficient. Solid-state quantum emitters deterministically coupled to nanophotonic circuits have overcome this challenge, and today highly efficient and coherent photon-emitter interfaces are realized, enabling generation of high-quality single-photon sources, multi-photon entanglement sources or photonic quantum gates. In this webinar we will explain the fundamental operational principle of this novel light-matter interfaces and discuss future application areas within quantum computing and quantum networks. Originally aired March 2022.

After the demonstration of the laser in 1960, researchers quickly discovered that tightly focused laser pulses generated a bright spark of ionized air. The physics of this process—a laser-driven exponential growth of charge—was well-understood by the end of the 1960s. An obvious potential application was extreme sensitivity charge detection in gases through the amplification of individual free electrons, in analogy to the detection of single photons or electrons by multiplier tubes. However, various technical and physics limitations delayed this application until very recently. In this presentation we will describe the avalanche process and discuss how we overcame these limitations to develop an ultrasensitive charge detection diagnostic. Originally aired March 2022.

Most colored materials owe their color to the absorption of light. In nature we often see a different type of coloration, known as structural color: certain wavelengths are transmitted, while others scatter and constructively interfere. Structural colors are common in birds and particularly in blue feathers, which consist of disordered arrays of pores that scatter light. Originally aired February 2022.

Whirlwinds caused by thermal updrafts can pick up dust and become visible, forming 'dust devils'. Largely a harmless curiosity in desert meteorology, they can cause occasional damage. Like earthquakes, there are many small ones, and a few intense ones; the distribution of diameters, or core pressure drops, seems to follow a power law…Watch the video to learn more! Originally aired January 2022.

The sparking of grapes in a household microwave oven has been a popular online parlour trick for decades. Traditional explanations presume that the objects act as conductive short antennas. However, attending to the bulk of these objects as aqueous dielectric spheres with an index of refraction of order 9 (at 2.5 GHz) provides new and exciting…Watch the video to learn more! Originally aired December 2021.