Fall 2023
Spring 2023
Fall 2022
Quantum Engineering Seminar

Thursday, November 3, 2022 @ 10:00 AM MST
Marquez Hall 126
Daniel Slichter

LASER-FREE ENTANGLEMENT AND SQUEEZING WITH TRAPPED IONS

More Info

Abstract: Trapped atomic ions in vacuum are a leading platform for quantum computing, sensing, and networking, thanks in part to their excellent coherence properties and the ability to manipulate and measure their quantum states with high fidelity. While quantum state manipulation in trapped ions typically relies on high-performance laser systems, our group is working to demonstrate high-fidelity control of trapped ions with rf/microwave magnetic and electric fields and gradients, with the goal of improving both performance and scalability. I will describe some recent results, including microwave/rf-based generation of entangled Bell states of ion spin with fidelity on par with that of the best laser-based demonstrations, and the use of laser-free trap potential modulation to perform strong unitary squeezing of ion motion, enabling sensing of electric fields below the standard quantum limit and enhancement of motion-mediated ion-ion entangling interactions. I will conclude by providing some perspectives on how laser-free control may offer advantages for large-scale trapped ion quantum computing.

 

Bio: Daniel Slichter is a staff physicist at in the Ion Storage Group at NIST in Boulder, CO. His research focuses on quantum information experiments with trapped atomic ions, with an emphasis on developing new paradigms for scalable trapped ion quantum computing and networking. Recent projects include performing high-fidelity entangling operations with microwave and rf fields instead of lasers; using strong unitary squeezing of ion motion to enhance ion-ion interactions and to perform electric field sensing below the standard quantum limit; and integrating superconducting photon detectors into microfabricated ion traps as an initial step in building a fully chip-integrated trapped ion quantum processor. Prior to NIST, he conducted research in superconducting quantum information, where he performed the first continuous high-fidelity measurement of a superconducting qubit, studied quantum feedback and measurement backaction, and worked on the development of near-quantum-limited microwave-frequency superconducting parametric amplifiers.

September 26 @ 11AM in CK282
RAYMOND SIMMONDS
NIST
Special QE Seminar: Engineering Parametric Interactions Between Superconducting Circuits
Abstract: Over 15 years ago, parametric coupling was proposed as a way to entangle flux qubits at their “sweet spots” with frequencies that were far detuned from each other. This was a possible solution to the difficulty with optimizing the spectrum of flux qubits that were extremely sensitivity to the variations in the critical current of their smallest fabricated Josephson junctions. After one major demonstration, this strategy was soon abandoned. In contrast, ion trap systems have always relied on parametric interactions that are naturally more flexible, allowing all-to-all tunable coupling between individual qubits. Over a decade ago, our group at NIST (in Boulder, CO) revived the parametric coupling strategy as a powerful tool for engineering interactions between superconducting circuits. In this talk, I will explain our parametric ideology and highlight our group’s continued efforts to develop non-resonant, parametrically induced coupled interactions between transmon-based qubits and cavities to enable fast, high fidelity gate operations and measurements. Finally, I’ll discuss improving, connecting, and expanding these systems for constructing analog quantum simulators or processing quantum information.

Spring 2022

March 1, 2022, 4:00 PM – 5:00 PM, CoorsTek 140/150
Honeywell/Quantinuum

TRAPPED ION QUANTUM COMPUTING

Abstract: Decades of progress in trapped ion quantum computing across academia, government labs, and industry enabled some of the world’s highest performing systems, improving our understanding of how to move forward in this emerging technology. Quantinuum is pursuing the quantum charge-coupled device (QCCD) architecture of trapped ion quantum computing and recently developed advancements in basic primitive operations of the architecture, ion transport, logical gates, and qubit initialization and detection, helping to define hardware for the next generation quantum computers. In parallel research tracks, current systems are used to gather crucial information about application performance in the areas of quantum error correction and simulations of quantum dynamics.

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.


March 29, 2022, 4:00 PM – 5:00 PM, CoorsTek 140/150
CTO and Founder of Atom Computing, Boulder, CO

An Old Qubit Contender Becomes New Again: Neutral Atoms

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.


March 31, 2022, 11:00 AM, Marquez 210
CEO & Cofounder, Vescent Photonics LLC, Golden CO, USA

Quantum Systems Will Change the World (Again), But Not Without Photonics and Not Without Colorado Talent

When systems are engineered to relay or extend “quantum weirdness” from the nanoscopic scale of atoms to the macroscopic scale of humans amazing things can happen. Twentieth century quantum systems (the transistor and the laser) ushered in the computer age and the information age, which changed the world. Twenty-first century quantum systems is just emerging, and the disruptive potential is equally tantalizing. Almost all these emergent quantum systems require lasers and photonics, representing both an opportunity and a challenge. In this talk I will discuss the complexity of the lasers-for-quantum space, present the technical and economic landscape, and pose possible paths forward for how lasers and photonics can usher in a new quantum age. I will also present how Vescent, a local company, is playing a critical role in this development and discuss how Colorado talent, at Vescent and in other Colorado Companies, is enabling the quantum 2.0 revolution.


SUPPORTING MINORITY SERVING INSTITUTIONS IN THE CREATION OF A DIVERSE, QUANTUM-READY WORKFORCE
COLORADO SCHOOL OF MINES
APRIL 8-9, 2022
ZOOM


April 12, 2022, 4:00 PM – 5:00 PM, Zoom
University of Oregon, Department of Physics

SPECTRALLY-MULTIPLEXED ENTANGLEMENT SWAPPING OF TIME-FREQUENCY ENTANGLED PHOTONS

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



April 19, 2022, 4:00 PM, Zoom
University of Michigan, Department of Electrical Engineering & Computer Science

BEYOND LIGHTING–GALLIUM NITRIDE FOR AUGMENTED REALITY, ROBOTICS, HEALTH CARE, & QUANTUM INFORMATION

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


For links to other quantum-related events, news, job opportunities, etc, check out PhD Physics student Farai Mazhandu’s Quantum@Mines Newsletter.


PHYSICS COLLOQUIUM SCHEDULE


QUANTUM ENGINEERING TRAINEESHIP EVENTS

Fall 2021
Colorado School of Mines, Department of Physics
November 16, 2021

The Center for Nonlinear Studies and Los Alamos National Laboratory
October 28-30, 2021
This workshop will be held in-person at the Drury Plaza Hotel in
Santa Fe, NM for those vaccinated against COVID-19 and will be broadcast to virtual participants. You must apply to attend in-person or register as a virtual attendee on the website in advance of the workshop.

University of South Florida
EDUCATING THE FUTURE QUANTUM INFORMATION WORKFORCE:
THE PEDAGOGY OF QUANTUM TECHNOLOGIES
September 3, 2021
10:00 AM ET
Online via Microsoft Teams

NSF
August 27, 2021
1-2:30 PM ET

 
Spring 2021
University of Wisconsin, Madison, Department of Physics

QUANTUM CONTROL OF SPINS IN SILICON

Quantum computing is based on the manipulation of two-level quantum systems, or qubits. In most approaches to quantum computing, qubits are as much as possible isolated from their environment in order to minimize the loss of qubit phase coherence. The use of nuclear spins as qubits is a well-known realization of this approach. In a radically different approach, quantum computing is also possible for strongly coupled multi-electron spin 1/2 systems, as realized in silicon-based devices. In this talk I will present both a historical overview of how quantum manipulation in silicon has developed, as well as the latest results from both our group at Wisconsin and from around the world. I will discuss our recent demonstration of coherent manipulation of eight different microwave-frequency resonances in a single silicon quantum dot, which starts to glimpse the future prospect of spin qubits being controlled using the types of powerful tools developed for controlling atoms by the AMO community over many decades. I will end with a brief discussion of how silicon fits into the broad quantum science and technology ecosystem, which is growing at an astounding rate. This article in Physics Today discusses closely related material: Quantum computing with semiconductor spins. Bio: Mark A. Eriksson is the John Bardeen Professor of Physics at the University of Wisconsin-Madison. He received a B.S. with honors in physics and mathematics in 1992 from the University of Wisconsin-Madison and an A.M. (1994) and Ph.D. (1997) in physics from Harvard University. His Ph.D. thesis demonstrated the first cryogenic scanned-gate measurements of a semiconductor nanostructure. He was a postdoctoral member of technical staff at Bell Laboratories from 1997-1999, where he studied ultra-low-density electron systems. Eriksson joined the faculty of the Department of Physics at UW-Madison in 1999. His research has focused on quantum computing, semiconductor quantum dots, and nanoscience. With collaborators he demonstrated the first quantum dot in silicon/silicon-germanium occupied by an individual electron and performed the first experiments to demonstrate the quantum dot hybrid qubit. Eriksson currently leads a multi-university team focused on the development of spin qubits in gate-defined silicon quantum dots. A goal of this work is to enable quantum computers, which manipulate information coherently, to be built using many of the materials and fabrication methods that are the foundation of modern, classical integrated circuits. Eriksson was elected fellow of the American Physical Society in 2012 and of the American Association for the Advancement of Science in 2015. All lectures are via Zoom

University at Buffalo, Department of Physics

SPIN QUBITS IN SI: COHERENCE AND CONTROL

Electron spin qubits in Si are promising candidates as building blocks toward future scalable quantum computers. Tremendous progress has been made in the past decade in demonstrating the exceptional coherence properties of spins confined in quantum dots and donors. However, studies of high-fidelity manipulation of spin qubits have encountered numerous problems as well: for donors, the small Bohr radius makes donor electrons hard to locate and control; for quantum dots, especially ones in Si/SiGe heterostructures, small valley splitting makes spin detection based on spin blockade difficult to realize. In this talk I discuss our recent work on spin manipulation and decoherence in Si quantum dots. I will first show that the complex valley-orbit coupling in a Si quantum dot can be significantly impacted by the atomistic scale features of an interface. The different valley mixing angles across a double dot would remove all valley selection rules in electron tunneling, and cause significant modification to the two-electron exchange coupling. On the decoherence front, I will discuss our recent study of spin relaxation in a Si quantum dot under the influence of a micromagnet that allows electrical control of single spins in Si. We show that the field gradient generated by a micromagnet amounts to an artificial spin-orbit interaction. However, unlike intrinsic spin-orbit coupling, which causes only spin relaxation, a micromagnet would cause both spin relaxation and pure dephasing, and generate a longitudinal effective field that could potentially be used for spin manipulation. We thank support by US ARO. Short Bio: Xuedong Hu is a physics professor at the University at Buffalo, the State University of New York. He received his PhD degree in condensed matter theory from University of Michigan in 1996, supervised by Franco Nori. He was introduced to the field of solid state quantum information processing in 1998 as a postdoc in Sankar Das Sarma’s group at the University of Maryland. His recent research focus is on spin qubits in silicon.

Monday–Friday, March 15–19, 2021, virtual APS March Meeting 2021


March 2, 2021, virtual
University of Colorado @ Boulder, JILA

METROLOGY WITH OPTICAL TWEEZER ARRAYS OF NEUTRAL ATOMS

Quantum science with neutral atoms has seen great advances in the past two decades. Many of these advances follow from the development of new techniques for cooling, trapping, and controlling atomic samples. As one example, the technique of optical tweezer trapping of neutral atom arrays has been a powerful tool for quantum simulation and quantum information, because it enables control and detection of individual atoms with switchable interactions. In this talk, I will describe ongoing work at JILA where we have explored a new direction for the optical tweezer platform: metrology. I will report our recent progress towards combining scalability and quantum coherence in a tweezer-based optical atomic clock platform, and our efforts towards using quantum information concepts and many-body dynamics to create entangled states that enhance metrological performance. Much of this technology is based in the use of tweezer-trapping of a new family of atoms, alkaline-earth atoms — I will discuss the broader outlook of this direction and new pursuits on the horizon. Recorded Video Link Tweezing a New Kind of Atomic Clock Bio: Dr. Adam Kaufman is an associate JILA fellow and assistant professor adjoint at CU Boulder. He did his PhD at JILA, studying few-body quantum mechanics of atoms in optical tweezers. Afterwards, as a postdoctoral fellow at Harvard, he investigated the dynamics of entanglement in thermalizing many-body systems and other Bose-Hubbard phenomena. In 2017, he moved back to JILA where he has continued working in the field of quantum science with neutral atoms. He is a winner of the prestigious APS DAMOP thesis prize in 2016, and he pioneered the research on atomic clocks based on optical tweezers.

February 25-26, 2021, virtual NSF Workshop on Quantum Engineering Education

Fall 2020

 

Colorado School of Mines
Denver University

AN INTRODUCTION TO OPTICAL VORTICES AND TOPOLOGICAL FLUIDS OF LIGHT

 Hydrodynamic whirlpools have fascinated scientists for centuries, seeking to understand their individual structure, stability, and the ways in which they interact with one another. Who hasn’t marveled at tornadoes or watched as soap bubbles get sucked into the vortex of a bathtub drain? To reduce ideas to their essence, such fluid vortices are often considered in a two-dimensional setting where they amount to current swirling around a singularity. These, in turn, bear a striking resemblance to cross-sections of optical vortices that can be created with lasers, but with the propagation axis now treated as time. The vortex center is a then a dark spot about which the phase of light rotates like a barber shop sign. Such engineered light can therefore be interpreted as a two-dimensional, compressible fluid, and the vortices it harbors exhibit all sorts of odd and potentially useful behavior. For instance, optical vortices can attract, repel, scatter, and even annihilate one another. Even more intriguing, these two-dimensional topological objects have a lot in common with the macroscopic quantum states of Bose-Einstein condensates and fractional quantum Hall systems. Pairs can even be used in Bell tests to demonstrate lack of local realism. This motivates a serious consideration of optical vortices as quantum objects that might be harnessed in emerging quantum information technologies. With these deeper issues in mind, our colloquium lecture is intended to serve as an introduction to optical vortices and their classical few-body dynamics. We tag-team an experimentalist and a theorist to provide a fuller perspective of what makes this form of light so interesting.

University of New South Wales

QUANTUM-COHERENT SILICON ELECTRONICS

Silicon is an attractive materials platform for developing large-scale quantum computers because of its compatibility with classical silicon electronics and its potential for scalability. This talk will discuss qubits made from quantum dots with multiple electrons in silicon/silicon-germanium heterostructures. These qubits can be manipulated on nanosecond time scales, and their coherence can be extended greatly by appropriate manipulation protocols. They can be tuned so that additional quantum resonances appear that can be driven coherently, which we show is consistent with effects arising form strong electron-electron interactions. Thus, these multi-electron qubits are interesting both as building blocks for quantum computers and as testbeds for investigating strongly interacting electrons. Recorded Video Link

August 13, 2020, virtual 6th Front Range Advanced Magnetics Symposium (FRAMS)


May 26, 2020, virtual Open Quantum Frontier Institute Virtual Workshop: Quantum Education 2nd workshop of the Open Quantum Frontier Institute


April 13-14, 2020 Dr. Zaira Nazario IBM Dr. Nazario will present on quantum computing. CANCELLED


February 28, 2020, 2-3 pm in CoorsTek 282 Fernando Sols Universidad Complutense de Madrid Departamento de Física de Materiales

Protected cat states in a driven superfluid boson gas

We investigate the behavior of a one-dimensional Bose-Hubbard gas in both a ring and a hard-wall box, whose kinetic energy is made to oscillate with zero time average, which suppresses first-order particle hopping while allowing even higher-order processes [1]. At a critical value of the driving, the system passes from a Mott insulator to an exotic superfluid phase. The system in the ring has similarities to the Richardson pairing model which can be exploited to understand key features of the interacting boson problem [2]. The superfluid ground state is a macroscopic quantum superposition, or cat state, of two many-body states characterized by the preferential occupation of opposite momentum eigenstates. Interactions give rise to a reduction (or modified depletion) cloud that is common to both macroscopically distinct states. Symmetry arguments permit a precise identification of the two orthonormal many-body branches forming the ground state. In the ring, the system is sensitive to variations of the effective flux but in such a way that the macroscopic superposition is preserved. We discuss other physical aspects that contribute to protect the catlike nature of the ground state. [1] G. Pieplow, F. Sols, C. E. Creffield, New J. Phys. 20, 073045 (2018). [2] G. Pieplow, C. E. Creffield, F. Sols, Phys. Rev. Research 1, 033013 (2019).

February 21-22, 2020 at the Colorado School of Mines in Golden, CO Open Quantum Frontier Institute 1st workshop of the Open Quantum Frontier Institute


September 16-17, 2019 in Alexandria, VA Quantum Simulators: Architectures and Opportunities US NSF-supported workshop See more on the Quantum Engineering @ Mines Workshops page link.

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