Previous APMS Colloquia

Fall 2023

Thursday, November 16, 3:00-4:00 pm

Materials and Chemical Research for Our Energy Future

Abstract: The clean energy transition requires access to terawatts of renewably generated electricity and gigatons of sustainably produced fuels. Advances in materials and chemical processes are critically needed to enable the technologies that will deliver both. Toward this end, the National Renewable Energy Laboratory (NREL) performs a broad array of research focused on the science and development of clean energy technologies. In this presentation, I will talk about NREL’s mission as well as our materials and chemical research. Topics include photovoltaics, electrochemical engineering, materials and processing for batteries, membranes for separations, new concepts for low-power computing, and advanced microscopy. I will also highlight ways in which to work with NREL, including internships, postdoc positions and collaborations.

Thursday, November 2, 3:00-4:00 pm

Quantum Information Science as a Probe of Fundamental Physics

Abstract: In the early 20th century science underwent a “quantum revolution” where the development of quantum mechanics fundamentally changed the way we understand the universe. Now, 100 years later, we are in the middle of a 2nd quantum revolution. The field of Quantum Information Science aims to use the strange properties of quantum mechanics for applications like quantum sensing and quantum computing. In this talk I will discuss how advances in these efforts also enable researchers to experimentally investigate the strange and counterintuitive aspects of quantum mechanics at unprecedented levels. Specifically, I will give a background of how gate-defined quantum dots work and how they can be used to examine the quantum measurement process and help shed light on what constitutes a measurement and the collapse of a wave function.

Thursday, October 26, 3:00-4:00 pm

Unveiling the Dynamics of Electron Flow in Quantum Constrictions using Machine Learning

Abstract: Scanning gate microscopy (SGM) is a powerful imaging technique that allows for the characterization of the coherent electron flow in low-dimensional structures such as quantum constrictions and short quantum wires. The technique utilizes the effect of a charged scanning probe on the electron flow, resulting in a signal that can be related to the local density of states of the device. However, obtaining meaningful information from SGM measurements can be challenging due to the stringent conditions required for the technique to be effective. In this seminar, we will discuss how to use machine learning approaches to estimate the background disordered potential of quantum constrictions from SGM. This approach involves matching SGM signals obtained through a weak perturbation approach to a corresponding background potential, and then using transfer learning to experimental SGM images. By studying the potentials that a single electron would experience, this approach enables the characterization of the disordered potentials and their impact on the electron flow in quantum constrictions.

Thursday, October 19, 3:00-4:00 pm

Enhancing the Performance of Quantum Key Distribution

Abstract: Quantum Key Distribution (QKD) is a relatively mature technology with the use of protocols such as BB84, Decoy, or EPR transmission; however, the high cost stucture, marginal transmitted distances, and incomplete security is limiting its deployment. The quantum error rates due to decoherence expand exponentially with the transmitted distances. Such a problem is partially mitigated at the expense of security by adding redundant information, data helpers, and error correcting codes. In this talk, the research effort conducted at NAU to enhance the performance of QKD will be summarized. We will present a method called “subset of responses” that allows the transmission of error free ephemeral cryptographic keys through quantum channels at longer distances in spite of high rates of decoherence. We will also explain why protocols using sources of single photons with multi-wavelengths combined with two state logics have the potential to further enhance QKD in terms of transmitted distances, throughput, and security.

Thursday, October 5, 3:00-4:00 pm

Quantum Information Science at Sandia National Laboratories

Abstract: This talk will give an overview to Quantum Information Science work at Sandia National Laboratories including computing projects such as the DOE/ASCR Quantum Scientific Computing Open User Testbed (QSCOUT) and the DOE Quantum Systems Accelerator, as well as quantum sensing applications in navigation, timing, and field sensing.

Bio: Dr. Muller is the Senior Manager of the Quantum and Advanced Microsystem group at Sandia and manages the Sandia portfolio in Quantum Information Science. Rick is also Director of the Quantum Systems Accelerator, one of the five DOE National Quantum Information Science Research Centers, which is co-led by Lawrence Berkeley National Laboratory and Sandia, and includes collaborators at Harvard, MIT, Caltech, Duke, Berkeley, and other institutions. Rick came to Sandia in 2003, after serving as a director of the Materials and Science Simulation Center at Caltech, which followed a postdoctoral fellowship with Nobelist Arieh Warshel at the University of Southern California and doctoral work with Bill Goddard at Caltech, all in Computational Chemistry. Rick did his undergraduate work in Chemistry at Rice University and Oriel College, Oxford. Prior to joining MESA, Rick was a Distinguished Member of the Technical structure theory and quantum device modeling and a manager in the Material, Physical, and Chemical Science Center. Rick spent 2016-2017 in Washington, D.C., working for the National Strategic Computing Initiative. Rick was raised near Chicago, IL, and when not at work enjoys biking and hiking on New Mexico trails, and spending time with his wife, Tess, and son, Alex.

Thursday, September 28, 3:00-4:00 pm

Organometallic Complexes for Non-Linear Optics

Abstract: This talk will describe previous research by Dr. Hurst on a specific class of organometallic complexes and how such materials have been used to quantify the effect that structural modifications have on non-linear optical responses.

Thursday, September 14, 3:00-4:00 pm

Career Pathways for Physics Degree Holders

Abstract: An education in physics offers a lot of pathways to success from industry, to government positions, to academic professorships. Over the last few decades, the American Physical Society has collected statistical data about the career trajectories of students at every level of physics education. We will discuss the data in detail and give insight that while most physics PhDs end up NOT being academic professors, the vast majority of them still do research in their careers – and are happy, especially compared to the general population. Current PhD students should see this as a great opportunity to explore the options available post-graduation, while undergraduates can weigh the potential benefits of attending grad school in the future. The data and slides presented in this talk are provided by the American Physical Society Career Mentoring Fellowship Program.

Thursday, September 7, 3:00-4:00 pm

Introduction to Quantum Computing and Quantinuum

Abstract: This presentation introduces quantum computing and highlights the innovations of Quantinuum, a leading full-stack quantum computing company. At the heart of Quantinuum’s approach is the integration of cutting-edge trapped-ion quantum commputing hardware with software tools to investigate solutions to problems in diverse areas such as cybersecurity, drug discovery, materials science, and finance. We’ll explore the enthusiasm around quantum computers, delve into their fundamental concepts, and discuss the nuances of quantum circuits. Attendees will gain insights into “TKET”, a versatile open-source quantum software development kit crafted without favoring any particular quantum architecture. As we wrap up, we’ll shed light on the emerging job opportunities within the quantum computing landscape.

Spring 2023

Thursday, May 3, 4:00-5:00 pm

Engineering Next Generation Chip-Based Atomic Clocks

Abstract: Atom-based clocks and sensors offer quantum enhancement over their classical counterparts, but many applications have been hindered by the size, weight, and power (SWaP) of existing laboratory systems. Recently, advances in compact vacuum technology, microfabricated traps, and integrated photonics show promising avenues toward deployable solutions for precision navigation and timing (PNT) applications. One such application is atomic clocks, which form the basis for modern communication and navigation. While many atomic clocks are room-sized systems requiring bulky free space optics and detectors, the Trapped-Ion Clock using Technology-On-Chip (TICTOC) project at Sandia National Laboratories aims to integrate these components into existing surface trap technology via waveguides for beam delivery and avalanche photodiodes for light detection. In this talk, I’ll discuss surface trap technology with integrated waveguides, detectors, and compact vacuum systems for low SWaP deployable clocks. In addition, I’ll provide a brief overview of the Quantum Scientific Computing Open User Testbed (QSCOUT), Sandia’s quantum computer based on trapped ions running external user-driven research projects.

Thursday, April 27, 4:00-5:00 pm

Modulating the Surface, Properties, and Shape of Artificial Bilayer Membranes

Abstract: In the Paxton Lab, we are developing stimuli-responsive supramolecular assemblies and synthetic models of cell membranes. We aim to understand, predict, and control their properties and functions of artificial membranes to develop new materials for drug delivery, designer interfaces, and soft nanomachines. This seminar focuses on our efforts to modulate the permeability and surface properties of synthetic lipid/polymer vesicles. I will also discuss our recent efforts to catalytically-activate changes in shape/morphology of pH- responsive micelles and vesicles.

Thursday, April 20, 4:00-5:00 pm

Defect and Strain Engineering: Advanced Characterization at the Nanoscale

Abstract: Control over disorder offers a promising route to design nanomaterial properties for integration into a wide range of existing and future applications relevant to energy, optical communications, and mechanical performance yet characterization to link experiment to theory is extremely challenging. In this talk I will given an overview of our recent results where atomic-scale non-equilibrium and disorder can bring about profound enhancements in both physical and chemical properties and review the new imaging techniques we are developing to establish atomic-level structure-transport property relationships in individual nanomaterials. Specific topics include our method to create deterministic single photon emission sites in epitaxial thin semiconductors, our discovery of the isotope effect of a two-dimensional transition metal dichalcogenide, structural characterization by large data sets collected using electron microscopy with patterned probes including our observation of strain related torsion in one-dimensional tellurium, and nano-thermal metrology techniques for measuring thermoelectric effects in isolated nanostructures. These capabilities have general implications to characterization of engineered materials.

APMS Colloquium

Thursday, April 13, 4:00-5:00 pm

Plasmonic Nanoparticle Platform for Spatiotemporal Controlled Delivery of Biomolecules into Cells

Abstract: This presentation highlights the development of plasmonic gold nanoparticles for spatiotemporal controlled delivery of biomolecules into cells. The nanoparticles were functionalized with ligands using thiol-gold chemistry to promote modular assembly of biomolecules on the surface. Near-infrared light was then used to cleave the thiol-gold bonds, releasing the biomolecule at the site of action within the cell. The successful development of this modular controlled cell delivery system will be discussed. The presentation will also briefly cover my post-doctoral work conducted at Los Alamos National Laboratory, which focused on using single-cell analysis to visualize intimate interactions between bacteria and fungi. Finally, I will conclude with a brief outlook on the future of my lab that will focus on generating tools to study microbial interactions in soil, new materials for bio preparedness, as well as the opportunities to perform collaborative research at the Center for Integrated Nanotechnologies.

Thursday, April 6, 4:00-5:00 pm

XPS Spectroscopy at UTEP

Abstract: By serendipity, a nuclear theorist has been involved in studies of materials surfaces with undergraduate students. In this talk, XPS is briefly introduced and several studies (ranging from cleaning water with tea leaves all the way to determining the temperature achieved in the Columbia shuttle explosion) are presented and used to remark the benefit of its use to train undergraduate students in research.

Thursday, March 24, 4:00-5:00 pm

Utilizing Education and Industry Partnerships to Promote Technological Education in Community College Micro Nano Technology Programs

Abstract: The Micro Nano Technology Education Center (MNT-EC) was conceptualized by educators in 2019 and funded by the NSF in 2020. The MNT-EC was originally founded on the idea that working together to accomplish a greater goal enhances the quality of education for students so that they may become higher quality technicians. The MNT-EC has four primary objectives including: 1) Developing a coordinated national approach to advance MNT education; 2) Delivering professional development to enhance knowledge, skills, and abilities; 3) Conducting strategic outreach, recruitment, and retention of traditional and underrepresented faculty/students; and 4) Creating a deep Industry/Education Alliance that supports student success. In this presentation we will discuss MNT-EC’s role in organizing a response to the CHIPS and Science Act for semiconductor technician education to provide community college students internships with a focus on hands-on learning experiences.

Thursday, March 9, 4:00-5:00 pm

Allostery and Protein Evolution Through Protein Conformational Dynamics

Abstract:  Proteins are the most efficient nano-machines and perform a broad range of functions. All of the information necessary for function is
encoded in 1-D sequences. Proteins exquisitely translate this code to fold and function, yet deciphering this encoded information remains an open challenge. With the advancement in sequencing techniques, inferring evolutionary record of extant proteins offers a tractable and highly effective solution to better understand the relation between sequence and protein function in order to decipher the 1-D sequence code. This is because evolution in itself has been a single massive ongoing experiment in diversification and optimization of protein sequence-structure-function relation occurring over billions of years. We have developed a physics-based metric called the Dynamic Flexibility Index (DFI) to study protein evolution. DFI quantifies the resilience of a given position to the perturbations occurring at various parts of a protein using linear response theory, mimicking the multidimensional response when the protein’s conformational space is probed upon interaction with small molecules or other cellular constituents. DFI provides us with an opportunity to retrace evolutionary steps which, in turn, have led to structural dynamics analysis of resurrected ancestral proteins. We demonstrated that protein static structures do not need to be modified in order for new function or molecular adaptation to emerge. Proteins may evolve and adapt new function by fine tuning their native state conformational dynamics. These studies provide us a molecular mechanism: Nature utilizes minimum perturbation-maximum response as a principle through the allosteric alteration of the dynamics of the active/catalytic sites by mutating distal positions, rather than introducing mutations on active sites. We also showed that this principle can be used to design proteins with desired function.

Thursday, February 16, 4:00-5:00 pm

Metalloprotein Engineering for Applications in Renewable Energy

Abstract:  Hybrid metalloproteins incorporating organometallic active sites not found in nature within a protein scaffold are emerging as a viable avenue to catalyze a wide range of reactions, with applications ranging from synthetic organic chemistry to sustainable fuel production. This approach is
particularly appealing when coupled with light as a source of energy to drive the synthesis of clean energy sources. We have designed artificial enzymes capable of producing molecular hydrogen and reducing carbon dioxide to carbon monoxide and formate under irradiation with UV-vis light and in the presence of photosensitizers. The active site in these designs is either anchored to protein scaffolds using noncanonical amino acids or obtained by swapping heme for cobalt protoporphyrin IX in natural and designed heme-binding proteins. Intriguingly, these constructs are active in aerobic conditions. We found that incorporation in a protein scaffold increases activity by 10-20 folds compared to the isolated organometallic complex. Transient spectroscopy analysis demonstrates that this effect correlates with increased lifetime of the catalytically active redox state. Current work examines the activity of these constructs within bacterial cells.

Thursday, February 9, 4:00-5:00 pm

Materials Science in Pre Hispanic America

Abstract:  Indigenous cultures in the American continent develop amazing materials technology long before the Spanish conquest. They had technologies to produce sophisticated metallic alloys and composite materials. Whereas their astronomy knowledge has been recognized their achievements in material science are not. In this talk we will describe some of their achievements. We will discuss in particular the paint know as maya blue which resisted 500 years in harsh conditions without deteriorating and the Au-Cu alloy known as “Cambalache” which was used to survive the Spanish demands for gold.

Thursday, February 2, 4:00-5:00 pm

Deterministic Quantum Mechanics

Abstract:  A deterministic quantum mechanics theory is presented. The proposed theory is shown to be consistent with the current mainstream statistical quantum theory as well as with classical physics. It produces solutions, which demonstrate that causality, physical reality, and determinism are restored and can explain in simple form concerns that are raised by results from the current mainstream statistical quantum theory. The meaning of particle-wave duality and complementarity, the possibility of a particle, like the electron, to cross through the nucleus as it does when the angular momentum of the electron is zero at the ground state of the hydrogen atom, the possibility of a point-size particle to have an “intrinsic spin”, the possibility of “quantum jumps” as the electron transitions instantaneously from one stable orbital to another without passing through the space in between the orbitals and does that at irregular time intervals, and the natural collapse of the wave function as part of the solution are some of the results that emerge from the proposed deterministic quantum mechanics theory. The phenomenon of entanglement is also discussed in connection to the proposed theory and linked to the EPR paper and the Bell inequality violation by experiments demonstrating how non-locality and reality can coexist in realistic and classical form. Actual analytical solutions that are consistent with current mainstream quantum theory as well as with classical physics are presented via a linear stability method.