Previous APMS Colloquia
Fall 2022
Thursday, December 8, 4:00-5:00 pm
Michael Jaden Brewer(NAU)
Quantum Game Theory: An Application to Quantum Information Science
Andrew Shepherd(NAU)
Quantum States of Sound
Ysaris Sosa(NAU)
Dynamic Photonic Communication in Supramolecular Polymer Composites
Thursday, December 1, 4:00-5:00 pm
Philip Asare(NAU)
Circular Dichroism in Hybrid Chiral Nanostructures
Eva Beeching(NAU)
Magnetic maze design for catalytic microswimmers
Alondra Hernandez-Cedillo(NAU)
Salivary sialic acid as a biomarker for disease screeing using nanotechnology
Madison King(NAU)
Novel Materials for electro-optical transduction in a quantum network
Thursday, November 17, 4:00-5:00 pm
Prof. Ying-Chen “Daphne” Chen
(NAU)
Beyond CMOS: Novel Materials, Emerging Memory and Applications
Abstract: Towards the end of the Moore’s law scaling approaching, there is a need for new semiconductor device technologies and microelectronics that break the limits of computing performance at the nanoscale while enabling better energy efficiency. We also need to consider a new approach with the new materials and new devices for exploring new paradigms of computing. Among the emerging technologies, emerging memory becomes the candidates for enabling the highly efficient computing while with nonvolatile effect for storage and computational applications. This research group aims to introduce the current develop of novel materials and emerging electronics, such as the selectorless memristor in high storage memory integration, neuromorphic computing systems, novel manufacture, reprogrammable one-time memory and non-continuous-structured materials for next-generation memory device and computational applications.
Thursday, November 10, 4:00-5:00 pm
John Castaneda(NAU)
Characterization of Light Activated Microswimmers for Controllable Motion
Alex Lehr(NAU)
Multimetallic Alloy Nanoparticles
Blake Rogers(NAU)
The New TEM Talos 200i
Thursday, October 27, 4:00-5:00 pm
Prof. Ryan Behunin
(NAU)
Quantum states of sound using nonlinear optics
Abstract: Owing to their long lifetimes at cryogenic temperatures, mechanical oscillators have been recognized as an attractive resource for quantum information science and as a testbed to explore fundamental physics-ranging from dark matter detection to the mechanisms underlying decoherence. Key to many of these applications is the ability to prepare, manipulate and measure quantum states of mechanical motion. In this talk, I’ll show how tripartite optomechanical interactions, involving the mutual coupling between two distinct optical modes and an acoustic resonance enables quantum states of mechanical oscillators to be synthesized and interrogated. I’ll present an exact formal solution to the Schrodinger equation for this nonlinear system. This result shows that highly-entangled quantum states can be generated using lasers and cryogenics, and that conditional measurements of the optical fields can project the mechanical oscillator into a wide variety of quantum states. Even without state-collapsing measurements, quantum coherence of the mechanical oscillator can be achieved. For the purposes of state tomography, I’ll show how this tripartite coupling permits an optomechanical analog π/2- or π-pulses that generate phonon-photon entanglement or transfer quantum states between the mechanical and optical domains using a classical coherent drive.
Thursday, October 13, 4:00-5:00 pm
Prof. Carlo R. daCunha
(NAU)
Probing Electrical Properties of Nanostructures With Scanning Gate Microscopy
Abstract: Scanning Gate Microscopy (SGM) is one of the scanning probe techniques where a charged tip perturbs an electron sea while changes in electrical conductivity are concomitantly measured. Under very strict conditions such as a sufficiently weak perturbation caused by a delta-shaped potential, the SGM signal shows some correspondence with the local density of states of the device. Using this technique, we were able to image quantum interference patterns inside a quantum point contact fabricated on an InAlAs/InGaAs heterostructure. Fine analysis reveals that these patterns are a result of quantum chaos in the constriction. Moreover, regions of compressibility in the quantum Hall regime were also imaged using the technique. The necessary conditions for the SGM signal to directly map the local density of states are typically difficult to be met, and this may lead to improper interpretation of the images. On the other hand, many properties of the device can be obtained indirectly using computational statistics. For instance, we have used approaches such as cellular neural networks and evolutionary search to estimate the self-consistent background potential of the device. From the estimated images, we were able, for example, to infer the electron density.
Thursday, October 6, 4:00-5:00 pm
Prof. Peter R. Buseck
(Arizona State Univ.)
From Earth to Deep Space: A Half Century (Almost) of Nanomineralogy
Abstract: Transmission electron microscopy can be used to determine the crystalline structures and compositions of solids at the micrometer to sub-nanometer scale. The visualization of structural irregularities in crystals has allowed observation of reaction pathways through transitions and reactions “frozen” before completion. Such information helped reconstruct nominally solid-state processes that previously could only be inferred. Early examples of studies of a range of minerals will show the development of the technique and its applications. Ongoing work is the use of TEMs to study minerals at high pressure. The talk will emphasize features close to the atomic scale but, through the study of unique carbon species, will extend to the largest known regions – the interstellar medium.
Thursday, September 29, 4:00-5:00 pm
Prof. Abhaya K. Datye
(Univ. of New Mexico)
Single Atom Catalysis: From an Academic Curiosity to Industrial Applications
Abstract: Over the past decade, single atom catalysis has evolved from being an academic curiosity to one of the most widely studied methods for the synthesis of novel catalytic materials. The promise of single atom catalysts is to lower the requirements for platinum group metals by utilizing these metals more efficiently and to create novel catalytic pathways. For industrial applications, single atom catalysts need to be stable under reaction conditions and demonstrate durability during accelerated aging. Recent research shows pathways for scalable synthesis of single atom catalysts that might deliver catalysts meeting the thermal durability requirements of industry while yielding reactivity improvements over conventional supported metal nanoparticle catalysts. Since mobile single atoms constitute the dominant mechanism for catalyst sintering via Ostwald ripening, improving the stability of single atoms could help improve the durability of all heterogeneous catalysts used in industry. In this presentation we will describe recent work on an approach which we termed atom trapping. Our initial work focused on trapping volatile metal oxides such as PtO2, to improve the durability of Pt catalysts, but we are now learning how this approach can be more broadly applicable. We will describe how fundamental understanding of the stabilization of single atoms and sub-nanometer particles and clusters can be helpful in applications ranging from emission control to hydrocarbon conversion.
Thursday, September 22, 4:00-5:00 pm
Dr. Jennifer Hollingsworth
(Los Alamos National Laboratory)
Nanocrystal Quantum Emitters: From the Flask to Photonic Devices
Abstract: Despite their humble origin, colloidal quantum dots (QDs) and other nanocrystalline semiconductors prepared in simple laboratory flasks are finding real-world applications in demanding technologies from displays and lighting to photovoltaics and photodetectors, and in the future, they may be the basis for single-photon devices in quantum networks. Beyond quantum size control, we pursue an expanded “structural toolbox” to synthetically engineer this class of nanomaterial to realize specific novel and optimal photophysical properties. Here, I will describe our efforts to understand and control synthesis-nanostructure-properties relationships toward a materials-by-design approach to the next generation of useful semiconductor nanocrystals. Equally, I will describe efforts beyond synthesis to address the strict criteria for single-photon source applications through nanoplasmonics and nanophotonics integration.
Thursday, September 15, 4:00-5:00 pm
Professor Carlos R. Cabrera Martinez
(Univ. Texas, El Paso)
Electrochemistry at the Interface of Materials Science and Biosciences
Abstract: In this presentation I will focus on the work done in areas related to
sustainable energy, water reclamation and remediation, biomedical devices, and electrochemistry at microgravity. In the area of sustainable energy, our
lab has been working on the electrochemical synthesis of bulk catalyst materials with low or non- precious metal content for fuel cell applications. Our
group has developed the Rotating Disk Slurry Electrodeposition (RoDSE) technique for metal and bimetallic nanoparticle electrodeposition at high surface area carbon materials, such as Vulcan XC-72R. Galvanic displacement techniques have also been used to prepare Ag-Pd and Pt-M (M=Co, Cu, Ni) nanoparticle and nanowire catalyst in combination with RoDSE. These nanomaterials have been characterized for the oxygen reduction reaction (ORR) using the rotating ring disk electrode (RRDE) technique and Synchrotron Techniques such as operando X-ray absorption spectroscopy (XAS) and Extended X-ray Absorption Fine Structure (EXAFS). In the area of water reclamation and remediation, I will present our work on nano Zero Valent Iron (nZVI) nanoparticles for heavy metal sequestration and urease-P. Vulgaris for urea to ammonia conversion in urine purification bioreactor system. In the area of biomedical devices, our recent work on telomease activity sensing using gold interdigital electrodes and electrochemical impedance spectroscopy will be explained. Telomerase may be a cancer biomarker and a possible low-cost point-of-care cancer sensing device. Finally, I will present our autonomous electrochemical system for ammonia oxidation reaction studies, using platinum nanocubes, done at the International Space Station (ISS).
Thursday, September 8, 4:00-5:00 pm
Professor Hui Cao
(Yale University)
Random Lasers
Abstract: One essential component of a laser is the cavity, which provides optical confinement and feedback for lasing oscillation. In a highly disordered medium, light experiences multiple scattering and undergoes a random walk. Surprisingly, lasing can occur in a random system without well-defined cavities. Such lasers are called random lasers, whose development was dated back to the early years of laser development. Over the past three decades there have been extensive experimental and theoretical studies on random lasers. I will review the history of random laser development and introduce the lasing mechanism. I will also discuss the applications that will benefit from the unique characteristic of random lasers.
Thursday, September 1, 4:00-5:00 pm
Dr. William “Buzz” Delinger
(NAU)
History of Physics at NAU and Student Awards Ceremony
Abstract: Dr. William “Buzz” Delinger taught for 48 years in the physics department at NAU. For this seminar, he will give a brief history of the department and tell of some of the important events that occurred during his tenure. He will also present some information about the people who established awards for NAU physics students. For the awards ceremony, the names of students who received the physics awards for 2022 will be read, and the students will be congratulated for their academic achievements.
Spring 2022
Thursday, May 5, 4:00-5:00 pm
Dr. Danielle D. Harrier
(Exponent: Engineering and Scientific Consulting)
Tunable encapsulations: droplet-based microfluidics for the expansion of biodegradable polymer technologies
Abstract: Biodegradable polymers are synthesized via a ring-opening polymerization (ROP) process which is water-sensitive. The water sensitivity of the polymerization chemistry prevents any technique using water as a solvent or dispersion media, which ultimately sets a limit on the polymeric material accessible. This thesis describes a droplet-based microfluidic encapsulation strategy that protects the water-sensitive catalyst from the aqueous phase, allowing the ROP to proceed in an aqueous dispersion. The success of this approach relies on simultaneous precise control of the kinetics of polymerization, the rate of mass transfer rates, and fluid mechanics. We report, for the first time, the production of biodegradable polymer particles dispersed in water. In this work, we systematically investigated the process and formulation parameters that govern the stability of the micro-droplets during generation, flow, and collection. More specifically, we tune droplet viscosity, surface tension, and hydrophobicity to further shield the ROP catalyst in the aqueous dispersion. Herein, a set of design rules for the tuning of catalyst protection efficiency within the aqueous dispersion are detailed, which ultimately allowed us to perform another water-sensitive ROP to produce polyether particles in water. To demonstrate the power and versatility of the encapsulation methodology, we crosslinked both chemistries to produce biodegradable elastomers and crosslinked polyethers in continuous flow. This project identifies the fundamental guiding principles to encapsulate water-sensitive polymerization catalysts to yield novel spherical polymer particles dispersed in water.
Thursday, March 24, 4:00-5:00 pm
Dr. Volker Urban
(Oak Ridge National Laboratory)
Adding Neutron Scattering to the Experimental Scientist’s Toolbox?
Abstract: Experimental studies in materials sciences, physics, chemistry, and biology often involve spectroscopy, diffraction, or microscopy. Typically, beams of photons or electrons probe the material, and many different techniques are available. Similarly, neutron scattering uses a diverse array of instruments that can resolve both structure and dynamics in a wide variety of materials. In this seminar, I will first provide a general introduction and overview and address the question when to use neutron scattering. Then I will present examples of my research on polymers, soft matter, and biology, to illustrate concepts and capabilities of neutron scattering in greater depth. The seminar intends to provide an opportunity for beginning conversations about the potential for use of neutron scattering in the research conducted by the Dept. of Applied Physics and Materials Science at Northern Arizona University.
Thursday, March 24, 4:00-5:00 pm
Prof. Andrew Jayich
(UC Santa Barbara)
A radioactive optical clock
Abstract: The bottom row of the periodic table is famous for its radioactive elements, which compared to stable isotopes are little-explored. Many heavy radioisotopes have exotic nuclei which grant them enhanced discovery potential. Radioactive elements also hold promise for advancing technology. Modern atomic physics techniques, such as laser cooling and ion trapping, allow for efficient use of trace isotopes and their study in highly-controlled environments. In this context we will discuss our recent work with trapped and laser-cooled trapped radium ions. The radium ion holds promise for its use in an optical clock. The atom’s high mass makes it less sensitive to leading systematic uncertainties. The wavelengths needed for radium clock operation are in relatively photonic technology friendly parts of the spectrum, making it appealing to consider radium for realizing a robust and compact optical clock. In addition to its potential to advance timekeeping, the radium ion is also intriguing for synthesizing and controlling exotic radioactive molecules which could be used to sense new fundamental particles.
Thursday, March 3, 4:00-5:00 pm
Dr. Alicia B. Magann
(Sandia National Laboratory)
Quantum control in the era of quantum computing
Abstract: Laser fields tailored to interact with quantum systems on their natural, ultrafast time scales can provide an unprecedented degree of control over their dynamics. A longstanding dream has been to leverage these control capabilities towards high-value applications spanning physics, chemistry, materials science, and biology. However, the pursuit of these goals continues to be challenged by the prohibitive cost of quantum dynamics simulations, which are needed to support and inform quantum control advances in the laboratory.
Nevertheless, the future is bright. In this talk, I will discuss how quantum computing can alleviate these computational challenges and enable us to explore the principles and possibilities of quantum control in a scalable manner. To this end, I will introduce a hybrid quantum-classical algorithm that leverages quantum computing to facilitate simulation studies of quantum control. I will outline the associated costs, discuss different application areas, and consider the feasibility of its implementation on quantum computing devices available today.
Thursday, February 24, 4:00-5:00 pm
Prof. Swati Singh
(University of Delaware)
- Department of Electrical and Computer Enigeering
Mechanical sensors for exploring the dark sector
Abstract: When properly engineered, simple quantum systems such as harmonic oscillators or spins can be excellent detectors of feeble forces and fields. Following a general introduction to this fast growing area of research I will focus on using optomechanical systems as sensors of weak acceleration and strain fields. Ultralight dark matter coupling to standard model fields and particles would produce a coherent strain or acceleration signal in an elastic solid. I will discuss the feasibility of searching for this signal using various optomechanical systems. I will also show that current mechanical systems have the sensitivity to set new constraints on scalar field candidates for dark energy. Finally, I will briefly discuss the promise of quantum noise limited detectors in the search for beyond the standard model physics.
Thursday, February 10, 4:00-5:00 pm
Prof. Jennifer Blain Christen
(Arizona State Univ.)
- Associate Professor
- School of Electrical, Computer and Energy Engineering
From cancer to COVID, pivoting in the pandemic
Abstract: Medical diagnostics have become increasingly distributed with the availability of point of care (clinic-based) and point of need (at home or in field) testing. Currently, high sensitivity diagnostics are limited to laboratories or point of care equipment the size of a refrigerator to small car. While handheld devices have made some inroads (e.g. self-monitoring blood glucose and pregnancy test), they are limited to applications with high analyte concentrations. Rapid, colorimetric tests have met the need for rapid results with low infrastructure. Rapid flu, Zika, and even COVID colorimetric tests (color test strips) enable triage and help prevent transmission of infectious disease. However, they are generally considered non-quantitative or semi-quantitative at best.
Our work has focused on bridging the gap between the need for rapid results and highly sensitive, quantitative testing. With a focus on low resource settings, we have engineered a fluorescence-based testing system for point of need testing. This system has been demonstrated in India working with AIIMS (All India Institute of Medical Science) Delhi to address disproportionate mortality rates due to cervical cancer. As we were ramping up to a large clinical trial, the COVID-19 pandemic hit. We believed that our handheld, multiplexed, quantitative fluorescence-based system could be modified to enable RNA-based (gold standard) testing outside of a medical laboratory. Supported by the Arizona Department of Health Services, we navigated the hurdles of research in a pandemic. This presentation will cover the foundational technology and how we pivoted through the pandemic to enable point of need testing approaching diagnostic laboratory sensitivity.
Thursday, February 3, 4:00-5:00 pm
Dr. Kanu Sinha
(Princeton Univ.)
- Associate Research Scholar
- Department of Electrical and Computer Engineering
Engineering Atom-Field interactions in Nanoscale Quantum Optical Systems
Abstract: Interactions between atoms and electromagnetic fields are at the core of nearly all quantum devices, with applications ranging from building quantum computers and networks, communicating quantum information over long distances, and developing quantum sensors of increasing precision. The miniaturization of these systems is critical to increasing their modularity as well as improving the efficacy of light-matter interactions by confining electromagnetic fields in small volumes. Thus atom-field interactions at nanoscales become a pivotal aspect of understanding and designing novel photonic devices.
In this talk, I will discuss two specific challenges relevant to nanoscale quantum optical systems and ways to engineer them: (1) Fluctuation phenomena—Forces, dissipation and decoherence induced by fluctuations of the electromagnetic field limit the control and coherence of quantum systems at nanoscales. I will present an overview of ways to engineer fluctuation phenomena in nanophotonic systems, and discuss specifically how collective effects can be used to tailor fluctuation-induced forces between atoms and surfaces. (2) Collective atom-field interactions over long distances—Distant correlated atoms coupled via waveguides can exhibit surprisingly rich non-Markovian dynamics arising from the memory effects of their intermediary electromagnetic environment. I will discuss how such a system demonstrates collective spontaneous emission rates exceeding those of Dicke superradiance (‘superduperradiance’), formation of macroscopically delocalized atom-photon bound states and limitations on long-distance quantum information protocols. These ideas pave the way for building novel efficient light-matter interfaces and scalable quantum devices with long distance correlated quantum systems.
Thursday, January 27, 4:00-5:00 pm
Prof. John Hartwig
(Univ. of California, Berkeley)
- The Henry Rapoport Chair in Organic Chemistry
Changing chemical synthesis with catalysis
Abstract: From Prozac to perfume, sustainable plastics to solar energy, catalysis enables our current standard of living and controls our potential to progress sustainably. The reduced emissions of modern cars, the abundance of fresh food at our stores, the beginnings of green energy, and the new pharmaceuticals we use to treat disease are made possible by chemical reactions controlled by catalysts.
Research in my group has sought to design catalysts that can introduce and manipulate functional groups in both small and large organic molecules. These reactions encompass novel coupling processes(1) to facilitate the synthesis of medicinally important molecules, reactions that enable the introduction of fluorine and new fluoroalkyl substituents, and reactions that enable the introduction of functional groups into positions of molecules inaccessible by classical organic reactions.(2, 3) This lecture will introduce the importance of catalysis overall, some major challenges in the field, and ways that our group is seeking to address these challenges. Examples of important catalysts used today, and examples of strategies to discover and develop new classes of catalysts for future applications will be presented.
1. (a) J. F. Hartwig, K. H. Shaughnessy, S. Shekhar, R. A. Green, in Organic Reactions, S. E. Denmark, Ed. (John Wiley &
Sons, Winheim, 2020), vol. 100, chap. 14, pp. 853-958; (b) https://en.wikipedia.org/wiki/-
Buchwald%E2%80%93Hartwig_amination
2. I. A. I. Mkhalid, J. H. Barnard, T. B. Marder, J. M. Murphy, J. F. Hartwig, Chem. Rev. 110, 890-931 (2010).
3. S. N. Natoli, J. F. Hartwig, Acc. Chem. Res. 52, 326-335 (2019).
APMS Colloquium
Thursday, January 20, 4:00-5:00 pm
Dr. Kartik Srinivasan
(NIST, Joint Quantum Institute/University of Maryland)
Chip-integrated nonlinear light sources for deployable quantum technologies
Abstract: Nanophotonics provides the unprecedented opportunity to engineer nonlinear optical interactions through the nanometer-scale control of geometry provided by modern fabrication technology. In this talk, I will outline our laboratory’s efforts towards engineering nonlinear interactions to access a broad range of optical wavelengths, with a long-term goal of being able to develop methods and devices to access any optical wavelength of interest. I will focus on two specific device technologies, microresonator frequency combs and optical parametric oscillators, and discuss their development and potential application in areas such as optical atomic clocks. If time permits, I will also discuss how such nonlinear nanophotonic technologies can be used for the generation and transduction of quantum states of light.