Mar 20 | 2 - 3pm
JILA Fellows Adam Kaufman, Konrad Lehnert, and Mathias Weber

"You got the Job-Now What? Negotiation Tactics and Starting A New Position After Your Postdoc" Panel -- OtherJILA Postdoc Group Event
JILA X317
Abstract & Event Details

Learn about how to navigate and negotiate your career after your postdoc by attending this panel featuring 3 JILA Fellows. 

Mar 20 | 3:30 - 4:30pm
Dr. David Kelley

TBA -- Biochemistry Seminar
JSCBB Butcher Auditorium
Abstract & Event Details

Mar 20 | 4 - 5pm
Murray Holland / JILA, University of Colorado, Boulder

Programmable quantum sensing using ultracold atoms in 3D optical lattices -- Physics Department Colloquium
JILA Auditorium
Abstract & Event Details

Abstract: The creation of a matter-wave interferometer can be achieved by loading Bose-Einstein condensed atoms into a crystal of light formed by interfering laser beams. By translating this optical lattice in a specific way, the traditional steps of interferometry can all be implemented, i.e., splitting, propagating, reflecting, and recombining the quantum wavefunction. Using this concept, we have designed and built a compact device to sense inertial signals, including accelerations, rotations, gravity, and gravity gradients. This approach is interesting, since the atoms can be supported against external forces and perturbations, and the system can be completely programmed on-the-fly for a new design goal. I will report on experimental results in which atoms are cooled into a dipole trap and subsequently loaded into an optical lattice. Protocols for obtaining interferometry steps are derived via machine learning and quantum optimal control methods. Implementing these in the lab, I will show our recent demonstrations of a vector accelerometer capable of sensitively deducing the magnitude and direction of an inertial force in a single shot. I will discuss our vision to use this platform for remote sensing of Earth as part of the recently founded NASA Quantum Pathways Institute.

Mar 21 | 12:30 - 1:30pm
Allen Scheie / LANL

Witnessing quantum entanglement in solid state systems with neutron scattering -- OtherCenter for Experiments on Quantum Materials (CEQM) Seminar
Duane Physics Room G126
Abstract & Event Details

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. By processing neutron scattering data with entanglement witnesses, we are able to experimentally measure Quantum Fisher Information which puts experimental bounds on entanglement depth, and also define a quantum correlation length which can be probed at finite temperatures. We have demonstrated these methods for 1D and 2D quantum spin systems. Our hope is that these tools—which apply to any momentum-resolved probe of dynamic susceptibility—will shed light on the fundamental quantum properties of quantum materials where theoretical models are not forthcoming.

Mar 21 | 12:30 - 1:30pm
Allen Scheie (LANL)

Witnessing quantum entanglement in solid state systems with neutron scattering -- CEQM Seminar
Duane Physics Room G126
Abstract & Event Details

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. By processing neutron scattering data with entanglement witnesses, we are able to experimentally measure Quantum Fisher Information which puts experimental bounds on entanglement depth, and also define a quantum correlation length which can be probed at finite temperatures. We have demonstrated these methods for 1D and 2D quantum spin systems. Our hope is that these tools—which apply to any momentum-resolved probe of dynamic susceptibility—will shed light on the fundamental quantum properties of quantum materials where theoretical models are not forthcoming.
 

Mar 21 | 4 - 5pm
Matthew Norgren / LASP

Measuring the stratosphere: what balloons are really doing -- Laboratory for Atmospheric and Space Physics (LASP)
LASP - Space Science Building, SPSC-W120 & Zoom
Abstract & Event Details

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. In this talk, I will detail the activities at LASP to design and build instruments to study stratospheric aerosols, water vapor, and temperature. I will then provide an overview of what we have learned from the historical in situ aerosol measurement record. This record was established at the University of Wyoming in the 1970s, and its operations have recently transferred to LASP. Finally, I will discuss the upcoming third phase of the Startèole 2 long-duration balloon campaign: a CNES led mission investigating processes within the tropical tropopause layer. LASP is supplying three novel instruments to the endeavor.

Mar 22 | 4 - 5pm
Fabien Goulay / West Virginia University

Understanding hydroxyl radical gas phase and heterogeneous reaction mechanisms -- Phys Chem/Chem Phys Seminar
JILA Auditorium
Abstract & Event Details

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. The presentation will discuss the experimental and theoretical investigations of OH reactivity with a series of hydrocarbon reactants at the air-water interface and in the gas phase. Effects of resonance stabilization and surface-bulk partitioning will be highlighted.

 

Apr 3 | 4 - 5pm
Brad Marston/ Brown University

Waves of Topological Origin in the Fluid Earth System and Beyond -- Physics Department Colloquium
JILA Auditorium
Abstract & Event Details

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. In this talk I show that, as a consequence of the rotation of the Earth that breaks time reversal symmetry, equatorial Kelvin and Yanai waves emerge as topologically protected edge modes. The non-trivial topology of the bulk Poincaré
waves is revealed through their winding number in frequency - wavevector space. Bulk-interface correspondence then guarantees the existence of the two equatorial waves. I discuss our recent direct detection of the winding number in observations of Earth’s stratosphere. Thus the oceans and atmosphere of Earth naturally share basic physics with topological insulators. As equatorially trapped Kelvin waves in the Pacific ocean are an important component of El Niño Southern Oscillation, the largest climate oscillation on time scales of a few years, topology plays a surprising role in Earth’s climate system. We also predict that waves of topological origin will arise in magnetized plasmas. The waves may appear in laboratory plasma experiments, and they may also arise in the solar system and beyond.

 

Apr 5 | 4 - 5pm
Kevin Wilson / Lawrence Berkeley National Laboratory (LBNL)

Chemical Kinetics in Microdroplets -- Phys Chem/Chem Phys Seminar
JILA Auditorium
Abstract & Event Details

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. This challenge lies, in large part, in understanding the complex kinetic coupling of adsorption, desorption, and diffusion that link chemistry occurring at the surface of an aerosol or droplet with processes occurring in its interior. In this talk I will review our recent work combining novel single droplet experiments with stochastic reaction diffusion models to develop more robust understanding of reaction rates in small compartments where interfaces play a prominent role.

Apr 27 | 1 - 2am
Prof. Alysia Marino / Dept. of Physics, U. of Colorado Boulder

ZAP! Electricity & Magnetism -- CU Wizards Program
Duane Physics Room G1B30
Abstract & Event Details

May 18 | 9:30 - 10:30am
Prof. Eric Cornell / Dept. of Physics & JILA, U. of Colorado Boulder

SPEED! -- CU Wizards Program
Duane Physics Room G1B30
Abstract & Event Details

Jun 29 | 9:30 - 10:30am
Prof. Andrew Hamilton / Dept. of Astrophysical & Planetary Sciences & JILA, U. of Colorado Boulder

BLACKHOLES! -- CU Wizards Program
Fiske Planetarium
Abstract & Event Details
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