Spring 2022 Colloquia

Biography: Dr. Russell Stutz is currently leading the Commercial Products group of HQS, where he is responsible for the design and build of commercial quantum computers. He received his Bachelor of Science in Physics from the University of Kansas, taking a commission in the US Air Force through the ROTC program upon graduation. As an Air Force officer, he worked on laser research at the Air Force Research Lab, Directed Energy Directorate at Kirtland AFB, NM. Dr. Stutz received his PhD from the University of Colorado-Boulder in atomic, molecular, and optical physics in 2010 under the tutelage of his research advisor Eric Cornell. After receiving his PhD, Dr. Stutz has worked industrial research and development at AOSense, a small company in California developing quantum sensors, as well as Lockheed Martin in Colorado. He has been with Honeywell since 2016, and was one of the first employees at the Broomfield, CO site.

Abstract: Perspectives on responsible research in STEM fields in the United States have been based almost exclusively on micro-level, individualistic, and US-centric biomedical frameworks. This talk will expand dominant approaches to research ethics education in science and engineering by incorporating some missing dimensions: (1) the global and cross-cultural context of research; (2) the political context of research; (3) self-knowledge of researchers; and (4) research that involves the development/deployment of socially disruptive technologies (e.g., gene editing, AI and surveillance, and robotics). Attention to these dimensions is critical for navigating the emerging landscapes of responsible research in the global context.

Biography: Dr. Qin Zhu is Assistant Professor of Engineering Education & Ethics in the Department of Humanities, Arts & Social Sciences at the Colorado School of Mines. Dr. Zhu is also an affiliate faculty member in the Department of Engineering, Design & Society and the Robotics Graduate Program. Currently Dr. Zhu is serving as Editor for International Perspectives at the Online Ethics Center for Engineering and Science, Associate Editor for Engineering Studies, Chair of American Society for Engineering Education’s Division of Engineering Ethics, and Executive Committee Member of the International Society for Ethics Across the Curriculum. His research interests include the cultural foundations of engineering (ethics) education, global engineering education, and ethics and policy of computing technologies and robotics.

Neutral atoms trapped in optical tweezers are a promising platform for implementing scalable quantum computers. Here I introduce a system with the ability to individually manipulate a two-dimensional array of nuclear spin qubits. Each qubit is encoded in the ground state manifold of ⁸⁷Sr and is individually addressable by site-selective beams. We observe negligible spin relaxation after 5 seconds, indicating that T₁ ≫ 5 s. We also demonstrate significant phase coherence over the entire array, measuring T₂ ^⋆ = (21 ± 7) s. Capitalizing on these beneficial properties of our optical tweezer platform, we aim to scale this system to a larger array of qubits in a parallelizable manner. Furthermore, these qubits can be entangled utilizing site-selective Rydberg excitation creating a universal gate set.

Ben received his PhD at the University of Colorado Boulder where he worked on Optical Atomic Clocks. Afterwards he worked at Intel on classical computers, at Rigetti on Superconducting Josephson Junctions, and in 2018 founded Atom Computing. He is the CTO of Atom Computing directing R&D efforts both on current systems as well as future systems being built at Atom.

Abstract: The longstanding muon g-2 anomaly is perhaps the largest discrepancy in fundamental physics and could become the first laboratory discovery of physics beyond the Standard Model of particles and interactions. In this talk, I will review what it means to measure a magnetic dipole moment, categorize the different theoretical possibilities for new particles that resolve the anomaly, and present a road map for how to discover the new particles responsible (even in a worst case “nightmare” scenario). A decisive probe of the underlying new physics will involve a combination of rare particle decay searches, new muon beam fixed-target experiments, and possibly even a future muon collider.

Biography: Gordan Krnjaic got his BA from Reed College in 2005 (graduating alongside Prof. Kapit) and PhD from Johns Hopkins University in 2012. From 2012-2015 he was a postdoctoral fellow at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario and from 2015-2018 the David N. Schramm Theory Fellow at Fermilab. In 2018 he became an Associate Scientist at Fermilab and holds a joint appointment as Assistant Professor at the University of Chicago. His research is primarily in theoretical particle physics and cosmology with an emphasis on physics beyond the Standard Model.

Abstract: Every hot object emits electromagnetic radiation, which is called thermal radiation or thermal emission. Thermal radiation is a ubiquitous phenomenon, with examples including the light emitting from the sun or from an incandescent lightbulb. Even though thermal radiation has been well-known from the century-old Planck’s law, recent applications of thermal radiation in energy harvesting, radiative cooling, and sensing have led to a renewed research interest of this topic.

This talk aims to focus on three aspects of thermal radiation. First, I will talk about our effort to achieve precision measurement of thermal radiation. Based on this measurement capability, I will introduce depth thermography, a new metrology method that can measure the temperature distribution of an object as a function of depth. Further, I will talk about Planck spectroscopy, a spectroscopic technique that does not require wavelength-selective components such as prisms, gratings, or interferometers—instead using the temperature dependence of Planck’s law of thermal radiation. The last part of my talk will cover the manipulation of thermal radiation, where I will show nano-second modulation of thermal radiation via modulated emissivity, with a speed much faster than the thermal time constant of the emitter. This talk will conclude with a discussion of future research opportunities of thermal-radiation with quantum effects and strong nonlinear light-matter interaction.

Lecture will be held in CoorsTek 140

Abstract: The ability to render semiconductors into inks and to print them with bespoke properties promises the herald of next-generation low-cost printed semiconductor electronics for terrestrial and space applications. While several semiconductor inks have emerged including metal oxides, colloidal quantum dots, perovskites, polymers, and 2D materials, ink printing lacks the pristine quality achievable by conventional time-consuming and unscalable single crystal growth platforms that enable defect-free forms of matter. As the ink building blocks come closer and pack during thin-film formation, interfacial and microstructural complexity increases. The challenge is to achieve controlled film fabrication, crystallization, and packing of matter at high speed. Developing diagnostics that can provide insights into printed film quality is a first step toward addressing this challenge. I will talk about my research efforts that have drawn attention to the interfacial and microstructural complexity in printed electronics and the need to understand it to drive the lab-to-fab transition. I will elaborate on the key highlight of my prior research: high-speed coating of colloidal quantum dot optoelectronics and metal-oxide thin-film transistors. Design of these high-quality printed electronic devices was informed by insights gleaned from surface-sensitive photoemission spectroscopy and synchrotron-based X-ray scattering tools. Understanding of the electronic band structure and defect physics, and control over crystallographic texture will be highlighted as key enablers of new device design rules. I will close with an introduction to my proposed research program at the Colorado School of Mines which will establish quality control in printed electronics by combining interfacial and microstructural diagnostics. These insights will be used to develop ultra-thin oxide electronics, radiation-hard electronics for space, and recycled perovskite photovoltaics for circular economy. A consensus article on radiation-testing of perovskite semiconductors based on my ongoing NREL research work will lay the foundation of space-relevant research direction in my program.

Figure. Research vision of the proposed Kirmani laboratory.

Biography: Ahmad Kirmani is a postdoctoral researcher in the group of Dr. Joseph Luther at the National Renewable Energy Laboratory (NREL), CO, where he is leading a DOD-funded research thrust to explore solution-processed perovskite solar cells for space applications. Ahmad has a Ph.D. degree (2017) in materials science from the King Abdullah University of Science & Technology (KAUST) under the supervision of Prof. Aram Amassian (now, North Carolina State University) where he explored surface structure-property correlations in colloidal quantum dot photovoltaics. Prior to joining NREL, he was a guest researcher at the National Institute of Standards and Technology (NIST) working with Dr. Lee Richter and Dr. Dean DeLongchamp. While at NIST, he researched scalable coating of metal-oxide inks and colloidal quantum dot self-assembly using synchrotron X-ray scattering. His research interests include roll-to-roll compatible coating and characterization of inorganic semiconductor inks, such as colloidal quantum dots, perovskites, and metal oxides. Ahmad has published over 40 journal articles including first-authored papers in high-impact journals such as Joule, Advanced Materials, and ACS Energy Letters. He is also a volunteer science writer for the Materials Research Society (MRS) and has contributed 10 news articles, opinions, and perspectives.

Personal Website: www.ahmadrkirmani.com, Twitter: @AhmadRKirmani

Lecture held in CoorsTek 282

Abstract: Entanglement, the correlations displayed between sub- systems of a multipartite quantum system, is one of the most distinguishing properties of quantum physics and a significant resource for quantum information science and technology. Entanglement swapping is a protocol that enables entanglement of quantum systems that have never interacted. This protocol underpins efforts to realize large-scale quantum networks as the core element of quantum repeaters. Entanglement swapping between entangled photons has been experimentally demonstrated using photons entangled in their polarization, spatial, and temporal degrees of freedom. Here we focus on encoding information in the spectral-temporal mode of single photons. This allows for a multiplexed approach to entanglement swapping that can generate many different entangled two-photon states. The entanglement swapping protocol relies on multimode entangled photon-pair sources and the ability to perform spectrally-resolved single-photon detection. Experimental results demonstrating the generation of 5 nearly-orthogonal two-photon states is presented.

Biography: Brian J. Smith is Professor of Physics at the University of Oregon, where he leads the Optical Quantum Technologies (OQT) research group. Prior to this Dr Smith was Associate Professor of Experimental Quantum Physics in the Department of Physics at the University of Oxford from 2010 to 2016. He was a Senior Research Scientist at the National University of Singapore 2009-2010, where he worked on integrated quantum photonics, and quantum-enhanced sensing. He was a Royal Society Postdoctoral Fellow 2007-2009 at the University of Oxford where he worked on controlled photonic quantum state preparation and manipulation, quantum measurement characterization, and quantum-enhanced sensing. He obtained a PhD in Experimental Quantum Optics from the University of Oregon in 2007 and BA degrees in Physics and Mathematics from Gustavus Adolphus College in 2000. Smith’s current research interests lie in the general areas of quantum optics and quantum technologies and their use in probing fundamental quantum physics and realizing quantum-enhanced applications with performance beyond that possible with classical resources. In these fields he has developed approaches for producing non-classical states of light with well-defined mode structure based upon engineered nonlinear optics, methods to coherently manipulate such quantum states, and efficient means to measure the resultant states. Recently his efforts have focused on harnessing the temporal-spectral mode structure of light to enable realization of larger quantum systems. These quantum-optical tools have enabled him to examine fundamental questions in quantum physics, such as the commutation relations for creation and annihilation operations, and experimentally address various quantum-enhanced technologies, for example quantum-enhanced sensing and quantum communications.

Current research: Smith’s current research interests lie in the general areas of quantum optics and quantum technologies and their use in probing fundamental quantum physics and realizing quantum-enhanced applications with performance beyond that possible with classical resources. In these fields he has developed approaches for producing non-classical states of light with well-defined mode structure based upon engineered nonlinear optics, methods to coherently manipulate such quantum states, and efficient means to measure the resultant states. Recently his efforts have focused on harnessing the temporal-spectral mode structure of light to enable realization of larger quantum systems. These quantum-optical tools have enabled him to examine fundamental questions in quantum physics, such as the commutation relations for creation and annihilation operations, and experimentally address various quantum-enhanced technologies, for example quantum-enhanced sensing and quantum communications.

Lecture via Zoom

Abstract: Gallium nitride (GaN) semiconductors are best known for their revolutionary applications in creating significant energy savings for electric lights (Nobel Prize in Physics 2014). Unlike silicon and the majority of other compound semiconductor materials, GaN is piezoelectric due to its wurtzite symmetry which is noncentrosymmetric. The piezoelectricity creates an electric potential when the material is strained. The piezoelectric potential can cause the electrons and holes to be separated from each other, which is disadvantageous to their radiative recombination efficiency. However, if properly engineered, the piezoelectric potential can enable a suite of applications for future augmented reality, robotics, health care, and quantum information technologies. In this talk, I will introduce the idea of local strain engineering which allows us to engineer the piezoelectric potential in a nanometer length scale by using the GaN nanostructures. I will discuss how the nanostructure’s geometry can be used as a tuning knob to control the optical properties of the material. A simple theoretical model will be presented that can be easily adapted for device design. I will also give a brief overview on various potential applications with the main focus on quantum photonics.

Biography: P.C. Ku received his BS from the National Taiwan University and PhD from the University of California at Berkeley, both in electrical engineering. He was awarded the Ross Tucker Memorial Award in 2004 as a result of his PhD research. He was with Intel before joining the University of Michigan where he is currently a professor of electrical engineering and computer science. In 2010, he cofounded Arborlight that was dedicated to solid-state lighting system design and application. He received the DARPA Young Faculty Award in 2010.

Lecture via Zoom