Past Events

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Abstract: In order to harness the intrinsic ability of colloidal semiconductor nanocrystals to couple strongly with light, it is important to efficiently outcouple energy from photoexcited quantum dots (QDs), much like how nature uses molecular antennas to direct light during photosynthesis. This talk focuses on aromatic acceptor ligands for triplet-fusion based photon upconversion, where orbital overlap between the QD donor and molecular acceptor is critical for efficient energy transduction.

Abstract: Quantum neural networks have been widely studied in recent years due to their potential practical utility and recent results showing their ability to efficiently express cert

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Abstract: Symmetry and topology are two of the conceptual pillars that underlie our understanding of matter. While both ideas are old, over the past several years a new appreciation of their interplay has led to dramatic progress in our understanding of topological electronic materials. A paradigm that has emerged is that insulating electronic states with an energy gap fall into distinct topological classes. Interfaces between different topological phases exhibit gapless conducting states that are protected and are impossible to get rid of.

Abstract: Over that last 10+ years there has emerged some evidence that when a reaction vessel is reduced to the micron-sized dimensions (e.g. droplets), bimolecular reactions speed up by many orders of magnitude. The mechanism(s) for rate acceleration in droplets remains unclear but has clear implications for understanding the chemistry of atmospheric aerosols. A key uncertainty in the interpretation of droplet kinetics is how to properly link reaction rates measured in beaker scale containers with those occurring in micron-sized spaces.

Conventional quantum algorithms use certain resources that are assumed to be given at almost no cost but are hard to pro

This week's LASP Seminar, "Brines and Habitability on Mars," with Alejandro Soto has been cancelled.

Abstract: Wave interactions are responsible for the various aspects of the behavior of different systems in nature, including processes in the oceans and atmosphere, star hydrodynamics, and even the evolution of the Universe. Spin waves (and their quanta–magnons) in magnetically ordered materials are highly nonlinear compared to, for example, phonons or photons in solids.

Abstract: Symmetries and topology are central to our understanding of physical systems. Topology, for instance, explains the precise quantization of the Hall effect and the protection of surface states in topological insulators against scattering from disorder or bumps. However discrete symmetries and topology have not, until recently, contributed much to our understanding of the fluid dynamics of oceans and atmospheres.

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The next generation of logic devices may rely on very fast switching of magnetic states. In this thesis, I utilize ultrafast pulsed lasers to measure and manipulate magnetic states on their fundamental timescales: ranging from few-femtoseconds spin-transfers in Heusler alloys to magnetization reorientations in ferrimagnets which take tens of picoseconds. I utilize high harmonic generation to produce a tabletop extreme ultraviolet probe for resonant measurements.

Large ensembles of laser-cooled atoms interacting via photon-mediated interactions are powerful platforms for quantum simulation and sensing. In this work, I will present a cavity-QED system with matter waves coupled to a high-finesse cavity. In this system, we successfully generated entanglement between atomic momentum states and realized the first entangled matter-wave interferometer.

Abstract: Reactions of the hydroxyl radical (OH) in the gas phase and at the gas-liquid interface initiate and propagate complex chemical schemes in combustion, planetary atmospheres, and the interstellar medium. In aqueous aerosols, the confinement of the reactants near the air-water interface leads to complex behavior of the particle reactive uptake with particle composition. In the gas phase, the branching ratio between the abstraction and addition mechanisms is highly dependent on the reactant’s structure and the gas temperature.

Abstract: Circuit quantization is an extraordinarily successful theory that describes the behavior of quantum circuits with high precision.

Absract: The Earth’s stratosphere, which sits above the troposphere, is a difficult place to make measurements. The highest-flying aircraft can only reach the lowermost portion of the stratosphere, while space-based sensors orbiting well above are limited by technique. Balloons can profile in situ from the surface up to approximately 35 km. Thus, they are a critical measurement platform for investigating the stratospheric constituents and processes that play important roles in regulating Earth’s climate.

Abstract: Quantum materials promise new states of matter and platforms for next-generation electronics, but in many cases no tractable theoretical models exist for their behavior. Compounding this difficulty is the fact that their key properties—quantum entanglement—have been historically very difficult to probe. In this talk I discuss recent work to use neutron spectroscopy to probe many-body entanglement between electron spins in real solid state materials.