Spring 2023 Colloquia

Unless otherwise specified, all lectures will take place in CoorsTek 140 from 4:00 PM to 5:00 PM MST.
For more information, please contact Barbara Shellenberger.
January 17, Watching Electrons Move

KATHRYN HAMILTON
Universtiy of Colorado @ Denver, Department of Physics

Kathryn Hamilton

Abstract: Since their discovery in the late 1800’s, electrons have been a constant source of curiosity for scientists. Their properties and behaviour have been studied and harnessed to produce some of the greatest inventions of the past century, including electron microscopes and particle accelerators. However one fundamental question about their behaviour still remains: how do electrons move inside atoms and molecules?

Electron motion within atoms has proved difficult to study due to the incredibly short timescale it occurs on (the attosecond timescale, or 10-18 seconds). One method of capturing electron motion is to use very short laser pulses to take a series of snapshots of the system. This requires laser pulses shorter than the duration of the dynamics we want to observe (similar to using a short flash on a camera to obtain an image of a fast-moving object). The means to do this have only become possible in the past decade with the advent of new ultrashort (less than 100 as) lasers, which have become feasible due to a process called high‐harmonic generation (HHG).

Harmonic generation occurs when an atom is exposed to a short laser pulse. Electrons are removed from the atom by the laser field, accelerated, and then recombine with the parent atom emitting high-energy harmonic light. This light can then be manipulated to produce the attosecond pulses required to image electronic motion. Analysis of the spectra produced by harmonic generation can also give an insight on the attosecond‐scale dynamics of electrons. An accurate theoretical description of high harmonic generation would therefore be extremely beneficial for the advancement of attoscience.

To this end, a world‐leading computational method, known as RMT (R‐Matrix with Time dependence), has been developed at Queen’s University Belfast to model accurately and efficiently the behaviour of electrons in many‐electron atoms. In this seminar I will present recent results obtained using the RMT method, firstly to treat high-harmonic generation in two-color laser fields, and then on applications of the attosecond pulses generated during the HHG process to measure ionization delays.

Figure 1: High-harmonic spectrum of neon atoms irradiated by a two-color (800nm + 400nm) laser field. The red “v” shapes are spectral caustics, formed by the coalescence of two or more electron trajectories in the same energy space.

Figure 1: High-harmonic spectrum of neon atoms irradiated by a two-color (800nm + 400nm) laser field. The red “v” shapes are spectral caustics, formed by the coalescence of two or more electron trajectories in the same energy space.

Bio: Kathryn Hamilton is a new Assistant Professor at the University of Colorado Denver. Previously she was a Postdoctoral Research Scholar at Drake University in Des Moines, Iowa, where she worked alongside Prof. Klaus Bartschat on applying R-Matrix methods to treat a variety of atomic physics problems. She obtained her PhD in 2019 under the supervision of Dr. Andrew Brown and Prof. Hugo van der Hart at Queen’s University Belfast with a thesis entitled “R-Matrix calculations for ultrafast two-colour spectroscopy of noble gas atoms”. Her current research focusses on observing and controlling multielectron dynamics in atoms exposed to external laser fields, and electron collisions with atomic species. When she is not running code on supercomputers all over the world, she likes to play traditional Irish music and domesticate feral cats. Both activities produce very similar sounds.

For an example of her work, you can see the recent YouTube video https://youtu.be/fqNEhL3JBXA.

Special Seminar, Wednesday, January 18 @ 2pm on Zoom, Light topology interplay in strong-field physics driven by structured laser pulses
Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, Universidad de Salamanca, E-37008, Salamanca, Spain
 

Carlos Hernández-García Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, Universidad de Salamanca, E-37008, Salamanca, SpainThe development of structured ultrafast laser sources is a key ingredient to advance our knowledge about the fundamental dynamics of electronic and spin processes in matter. In particular, it has been widely recognized the relevance of ultrafast sources structured in their spin angular momentum (SAM, associated to the polarization of light) and orbital angular momentum (OAM, associated with the transverse phase profile, or vorticity of a light beam) to study chiral systems and magnetic materials in their fundamental temporal and spatial scales. In that scenario, structured coherent extreme-ultraviolet (EUV)/soft x-ray pulses are emerging as unique tools to drive strong field physics, particularly thanks to the new opportunities they provide in the highly nonlinear process of high harmonic generation (HHG) [1,2]. Cylindrical vector beams are paradigmatic examples of structured beams, being defined by topological parameters, such as the Poincaré index. It is known that the topology of vector beams is directly transferred to the high-order harmonics when HHG is driven in gas targets [3,4]. In this context, crystalline solids stand as particularly appealing targets in HHG due to their characteristic symmetries which imprint an anisotropic nonlinear response [5].In this talk we will review several works that have triggered the field of ultrafast structured EUV pulses during the last decade. We will compare the interplay of light and matter topology in HHG in gases and in crystalline targets. In particular, our macroscopic simulations of HHG in graphene [6, 7] allows us to study how the symmetry of the anisotropic response of the target couples with the driver’s topology. This scenario opens the route towards high-order harmonic spectroscopy techniques based on the topology of the harmonic radiation [7].[1] L. Rego, K. Dorney, N. Brooks, Q. Nguyen, C. Liao, J. San Román, D. Couch, A. Liu, E. Pisanty, M. Lewenstein, L. Plaja, H. Kapteyn, M. Murnane, C. Hernández-García, Science 364, eaaw9486 (2019).[2] L. Rego, N. J. Brooks, Q. L. D. Nguyen, J. San Román, I. Binnie, L. Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, Science Advances 8, eabj7380 (2022).[3] C. Hernández-García et al., Optica, 4, 520 (2017).[4] A. de las Heras,  A. Pandey, J. San Román, J. Serrano, E. Baynard, G. Dovillaire, M. Pittman, C. Durfee, L. Plaja, S. Kazamias, O. Guilbaud, C. Hernández-García, Optica 9, 71-79 (2022).[5] Ó. Zurrón-Cifuentes, R. Boyero-García, C. Hernández-García, A. Picón, L. Plaja, Opt. Expr., 27, 7776-7786 (2019).[6] R. Boyero-García, Ó. Zurrón-Cifuentes, L. Plaja, and C. Hernández-García,  Optics Express 29, 2488-2500 (2021).[7] A. García-Cabrera,  R. Boyero-García, Ó. Zurrón-Cifuentes, J. Serrano, J. San Román, L. Plaja, C. Hernández-García,

Friday, January 27 @ 1PM CTLM102, Chipps Speaker Series: From Timekeepers to Spies of the Quantum Realm
 
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Abstract: Harnessing the behavior of complex systems is at the heart of quantum technologies. Precisely engineered ultracold gases are emerging as a powerful tool for this task. In this talk I will explain how ultracold strontium atoms trapped by light can be used to create optical lattice clocks – the most precise timekeepers ever imagined. I am going to explain why these clocks are not only fascinating, but of crucial importance since they can help us to answer cutting-edge questions about complex many-body phenomena and magnetism, to unravel big mysteries of our universe and to build the next generation of quantum technologies.

 

 

Bio: Prof. Ana Maria Rey obtained her bachelor’s degree in physics in 1999 from the Universidad de los Andes in Bogota, Colombia. She pursued her graduate studies at the University of Maryland, College Park, receiving a Ph.D. in 2004. She then joined the Institute of Theoretical, Molecular and Optical Physics at the Harvard-Smithsonian Center for Astrophysics as a Postdoctoral Fellow from 2005 to 2008. She joined JILA, NIST and the University of Colorado Boulder faculty in 2008. She is currently a JILA and NIST fellow and a Professor Adjoint in the Department of Physics. Rey’s research focuses on how to control and manipulate ultra-cold atoms, molecules and trapped ions for use as quantum simulators of solid state materials and for quantum information and precision measurements. Rey’s recognition to her work include, among others a MacArthur Foundation Fellowship (2013) and the Blavatnik National Awards for Young Scientists (2019).

Friday, January 27 @ 1PM CTLM102, Chipps Speaker Series: From Timekeepers to Spies of the Quantum Realm
 
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Abstract: Harnessing the behavior of complex systems is at the heart of quantum technologies. Precisely engineered ultracold gases are emerging as a powerful tool for this task. In this talk I will explain how ultracold strontium atoms trapped by light can be used to create optical lattice clocks – the most precise timekeepers ever imagined. I am going to explain why these clocks are not only fascinating, but of crucial importance since they can help us to answer cutting-edge questions about complex many-body phenomena and magnetism, to unravel big mysteries of our universe and to build the next generation of quantum technologies.

 

Bio: Prof. Ana Maria Rey obtained her bachelor’s degree in physics in 1999 from the Universidad de los Andes in Bogota, Colombia. She pursued her graduate studies at the University of Maryland, College Park, receiving a Ph.D. in 2004. She then joined the Institute of Theoretical, Molecular and Optical Physics at the Harvard-Smithsonian Center for Astrophysics as a Postdoctoral Fellow from 2005 to 2008. She joined JILA, NIST and the University of Colorado Boulder faculty in 2008. She is currently a JILA and NIST fellow and a Professor Adjoint in the Department of Physics. Rey’s research focuses on how to control and manipulate ultra-cold atoms, molecules and trapped ions for use as quantum simulators of solid state materials and for quantum information and precision measurements. Rey’s recognition to her work include, among others a MacArthur Foundation Fellowship (2013) and the Blavatnik National Awards for Young Scientists (2019).

January 31, SUB-ATOMIC PARTICLE WINDOW TO THE ULTRA-HIGH-ENERGY UNIVERSE

ERIC MAYOTTE
Colorado School of Mines

Ultra-High-Energy cosmic rays (UHECRs) are the most energetic objects yet observed, and can have individual particle energies of 1020 eV. The field of physics which studies them is called astroparticle physics and it sits at the intersection of high-energy particle physics and multi-messenger astrophysics. The primary goals for this field of study are identifying the astrophysical mechanisms capable of accelerating particles to these extreme energies and leveraging UHECR to probe physics at energies far beyond what human made experiments are capable of producing in the near future.

Right now is an exciting time in astroparticle physics as practically all aspects of this field are undergoing a rapid evolution due to the availability of high-quality, high-statistics data-sets, advancing computational techniques, and revolutions in instrumentation design and scale [1]. A particularly exciting development is the advent of new analysis techniques which can map the particle universe at the highest energies using the composition of arriving cosmic rays. With this method, for the first time a composition dependent anisotropy in the UHECR sky has been identified and is approaching discovery status [2]. Furthermore, the anisotropy itself may be a significant driver of our understanding of the highest-energy extra-galactic systems, as its strength far surpasses those predicted with the most current astrophysical models [3].

This talk will give a brief overview of UHECR physics and where it is going over the next 20 years. Special attention is given to the technique of mapping the UHECR sky in terms of primary composition.

[1] A. Coleman, J. Eser, E. Mayotte, F. Sarazin, F. Schröder, D. Soldin, T. Venters et al., “Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers,” Astroparticle Physics Special issue 147, 5 2022.
[2] E. Mayotte et al., “Indication of a mass-dependent anisotropy above 1018.7 eV in the hybrid data of the Pierre Auger Observatory,” PoS, vol. ICRC2021, p. 321, 2021.
[3] D. Allard, J. Aublin, B. Baret, and E. Parizot, “What can be learnt from UHECR anisotropies observations? Paper I : large-scale anisotropies and composition features,” 10 2021.

Biography: Dr. Eric Mayotte is a Mines physics alum, having received both his undergraduate and PhD in the Mines Physics department. He currently works in high-energy astrophysics looking at both cosmic rays and neutrinos. His PhD, under Professor Fred Sarazin, focused on searching for exotic matter by identifying low-velocity, high-energy, particle showers in the ultra-high-energy cosmic ray data collected by the Pierre Auger Observatory and was awarded best physics thesis at Mines in 2016. in 2016 he took a post-doc position under the spokesperson of the Pierre Auger Observatory, Professor Karl-Heinz Kampert at the University of Wuppertal in Wuppertal, Germany. During this post-doc, Eric developed a first of its kind method to map out the high-energy particle universe using the chemical composition of arriving cosmic ray primaries. This work has led to the first ever identification of a composition anisotropy in the flux of cosmic rays which is nearing discovery status, and was given a best contributed talk award at the largest international conference on astroparticle physics (ICRC). In August 2021, Eric returned to Mines as a post-doc to collaborate with Professor Fred Sarazin in order to build a micro-cosmic ray observatory in Utah and is working on the development of a space-based high-energy neutrino simulation suite in a collaboration with NASA scientists. When not working on physics, you’ll often find him skiing at A-Basin, playing cribbage at GCB, or reading a book at Higher Grounds.

Friday, February 10 @ 1PM CTLM102 SUPERCONDUCTIVE ELECTRONICS AS A PATH FOR SCALABILITY OF QUANTUM COMPUTING

MANUEL CASTELLANOS BELTRAN
NIST

Manuel Castellanos BeltranAbstract: Over the last two decades there has been tremendous interest in the advance of large-scale quantum computers. In particular, superconducting quantum processors has become the leading candidate for scalable quantum computing plat-form. Some of the initial research that paved the way for this field to take off was done at NIST several decades ago. In this talk I will give a summary of how my research in superconductive electronics group at NIST is helping solve some of the issues of scalability that plague this technology. I will also talk about my academic trajectory: my winding path from being an undergrad in Monterrey, Mexico, to a permanent staff scientist at NIST as well as discuss some of the challenges I’ve had in my scientific career.

Biography: Dr. Manuel Castellanos Beltran attended college in Mexico at the Monterrey Institute of Technology and Higher Education (Monterrey, NL.) where he received his BE in Engineering physics in 2003. He then attended the University of Colorado-Boulder where he earned his PhD in physics in 2010 working on developing Josephson parametric amplifiers for Quantum Information applications and quantum limited measurements under the guidance of Dr. Konrad Lehnert. Afterwards, he worked at Yale University as a Post-Doctoral Fellow (2010-2012) under Dr. Jack Harris where he studied persistent currents in normal metal mesoscopic rings using torque magnetometry techniques. Dr. Castellanos-Beltran then joined NIST as a PREP Post-Doctoral Fellow (2012-13) and NRC Post-Doctoral Fellow (2013-2015) working with Dr. Jose Aumentado studying low noise amplification with Josephson parametric amplifier for Qubit Readout. He is currently a researcher for the Superconductive Electronics Group working in the development of a high frequency arbitrary waveform synthesizer using cryogenic superconductive electronics for microwave metrology and quantum computing applications.

February 14, TITLE TO BE ANNOUNCED
February 28, TITLE TO BE ANNOUNCED

DEJI AKINWANDE
University of Texas @ Austin, Chandra Department of Electrical and Computer Engineering

Deji Akinwande

Friday, March 10, TITLE TO BE ANNOUNCED

RAMON BARTHELEMY
University of Utah, Physics and Astronomy

Ramon Barthelemy

March 14, TITLE TO BE ANNOUNCED

MINGZHONG WU
Colorado State University, Department of Physics

Mingzhong Wu

April 4, TITLE TO BE ANNOUNCED

KAVEH AHADI
NC State University, Department of Materials Science and Engineering

Kaveh Ahadi

April 11, TITLE TO BE ANNOUNCED

ANDRÁS GYENIS
University of Colorado @ Boulder, Electrical, Computer & Energy Engineering

András Gyenis

April 18, TITLE TO BE ANNOUNCED

DAVE VENTURELLI
USRA Research Institute for Advanced Computer Science, Quantum AI Laboratory at NASA ARC

Dave Venturelli

April 25, TITLE TO BE ANNOUNCED
May 2 @ 4:00 PM - 7:00 PM, PHYSICSFEST - Into the Summer

Undergraduate Senior Design Poster Session