# Lecture Videos

In her talk, Grace Xing (Cornell University) describes the recent progress accomplished in her group in the field of 2D materials towards the fabrication of Thin-Tunneling Field-Effect Transistor (TFET) devices, where Thin stands for Two-dimensional Heterojunction Interlayer Tunnel.

Indeed, she describes how the group has been able to observe a 40 mV/decade subthreshold slope in 2D materials, which is an experimental first.

Sean Garrett-Roe (Pitt) presents the collaborative work fostered by PQI, between his experimental lab and the theoretical group of Daniel Lambrecht.

He describes the use of ultra fast spectroscopic techniques to provide molecular details about the interaction and dynamics of a molecule with its environment in the framework of CO2 capture in ionic liquids. The group uses the anti-symmetric stretch of the CO2 molecule as a probe to investigate the intermolecular interactions that lead to bulk properties.

In his talk, entitled "Bridging QM and Chemical Intuition", Daniel Lambrecht (Pitt) shows how quantum mechanics can inform conceptual thinking in chemistry.

He walks us through a well defined procedure that allows the calculation of "chemical" quantities that are not observables, for example the notion of charge transfer. The approach he describes is a flavor of energy decomposition analysis, and it can be applied to the calculation of properties such as vibrational spectra as demonstrated in their study.

The main topic of Ben Hunt's (CMU) talk is superconductivity in two dimensions.

He describes the new approach he developed with his team to make superconductors with the van der Waals heteromaterial NbSe2...and the surprising observation of a metallic state at non-zero temperatures.

This state is characterized by a resistance that is finite, independent of the temperature, and has a power-law dependence on the magnetic field.

Cyrus Umrigar (Cornell University) gives an in-depth description of various variational and projector Quantum Monte Carlo (QMC) methods that are used to computationally solve problems in chemistry and physics. He also addresses some of the current challenges in method development and application, namely the sign problem, as well as the current approaches to overcome the issue. Several methods are thus compared and contrasted throughout the lecture.

Nader Engheta (University of Pennsylvania) talks about some of the aspects of near-zero optics and applications in "extreme" optical materials. He introduces the notion of ‘static optics’, a state in which the the electric and magnetic fields are temporally dynamic but decoupled. This occurs in materials where both the relative effective permittivity and permeability attain near-zero values. Such "Near-Zero" structures show promise as platforms for quantum emitters, long-range entanglement, and quantum interference.

Martin Zwierlein (M.I.T.) talks about strongly interacting fermi gases of atoms and molecules. He introduces NaK, a chemically stable fermionic molecule studied in his group and explains the process of generating this molecule in the ground state with a high conversion efficiency and reasonable lifetime. He also describes the first studies of the hyperfine states of this new quantum system and how with two such states, they can build a molecular clock.

Martin Zwierlein (M.I.T.) talks about strongly interacting fermi gases of atoms and molecules. He introduces NaK, a chemically stable fermionic molecule studied in his group and explains the process of generating this molecule in the ground state with a high conversion efficiency and reasonable lifetime. He also describes the first studies of the hyperfine states of this new quantum system and how with two such states, they can build a molecular clock.

Doug Natelson (Rice University) talks about heating and vibrations at the molecular level. Non equilibrium heating is of much interest in physics although it is still difficult to obtain information about the local electronic or vibrational distribution. He therefore proceeds to describe the approach developed by his group towards simultaneous electron transport and Surface Enhanced Raman Spectroscopy with plasmons at the molecular-scale.

Xiao Yang Zhu (Columbia University) talks about many body coherent processes in semiconductors brought about by light-matter interactions with applications in solar energy conversion. He describes the recent experimental detection of phonon-assisted Auger recombination as well as the nature of the multi-exciton state and the role of vibronic coherent and incoherent rate processes in singlet fission.