Meetings & Workshops
Magnet Test Database Workshop (May 7, 2018)
2nd International Magnet Test Stand Workshop (May 8-9, 2018)
Proceedings of the 1968 Summer Study on Superconducting Devices and Accelerators
Talks
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SEP
3
Thursday
Quantum Thursdays Lecture Series
"Tantalum alloy–based resonators for quantum information systems"
Presented by Robert Cava, Princeton University
12 pm, Videoconference / Virtual Event
Thursday, September 3, 2026, 12:00 pm
Hosted by: Kai-Mei Fu - C2QA Deputy Director, University of Washington
Utilizing tantalum (Ta) in superconducting circuits has led to significant improvements, such as high qubit lifetime (T1) and quality factors in both qubits and resonators, suggesting that material optimization plays an important role in the development of superconducting circuits. Thus we here explore superconducting gap engineering in Ta-based devices as a powerful strategy for expanding the range of suitable host materials. By alloying 20 atomic percent (at.%) hafnium into Ta thin films, we achieve a superconducting transition temperature (Tc) of 6.09 K as observed in direct current (DC) transport measurements, reflecting an increase in the superconducting gap. We systematically vary deposition conditions to control film orientation and transport properties of Ta-Hf alloy thin films. We then confirm the enhancement in Tc via microwave measurements at millikelvin temperatures. We verify the 40 increase in Tc relative to bare Ta devices, while the loss contributions from two-level systems and quasi-particles remain unchanged in the low temperature regime. These findings emphasize the promise of material engineering in superconducting circuits and point to many potential material candidates for further exploration. Starts at 12:00 p.m. ET/9:00 a.m. PT.
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OCT
15
Thursday
Quantum Thursdays Lecture Series
"A 1 km photonic link connecting SC circuits in two dilution refrigerators"
Presented by Hong Tang, Yale University
12 pm, Videoconference / Virtual Event
Thursday, October 15, 2026, 12:00 pm
Hosted by: Kai-Mei Fu - C2QA Deputy Director, University of Washington
Superconducting quantum processors are a leading platform for implementing practical quantum computation algorithms. Although superconducting quantum processors with hundreds of qubits have been demonstrated, their further scale-up is constrained by the physical size and cooling power of dilution refrigerators. This constraint can be overcome by constructing a quantum network to interconnect qubits hosted in different refrigerators, which requires microwave-to-optical transducers to enable low-loss signal transmission over long distances. Although various designs and demonstrations have achieved high-efficiency and low-added-noise transducers, a coherent photonic link between separate refrigerators has not yet been realized. Here we experimentally demonstrate coherent signal transfer between two superconducting circuits housed in separate dilution refrigerators, enabled by a pair of frequency-matched aluminum nitride electro-optic transducers connected via a 1-km telecom optical fiber. The optical frequency matching between two transducers is realized by an asymmetric photonic molecule design, and an overall 80 dB improvement in transduction efficiency over commercial electro-optic modulators is achieved, paving the way towards a fully quantum-enabled link. This work provides critical design guidelines for scalable superconducting quantum networks interconnected by photonic links. Starts at 12:00 p.m. ET/9:00 a.m. PT.
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NOV
12
Thursday
Quantum Thursdays Lecture Series
"Hybrid oscillator-qubit quantum processors: Instruction set architectures, abstract machine models, and applications"
Presented by Steve Girvin, Yale University
12 pm, Videoconference / Virtual Event
Thursday, November 12, 2026, 12:00 pm
Hosted by: Kai-Mei Fu - C2QA Deputy Director, University of Washington
This tutorial offers a pedagogical guide to hybrid quantum processors that integrate discrete-variable (DV) qubits and continuous-variable (CV) oscillators. Aimed at computer scientists, engineers, and physicists, it provides an overview of the experimental, algorithmic, and architectural aspects of this novel and rapidly developing hardware model. Experimental realizations of this model include superconducting, trapped-ion, and neutral-atom platforms. By combining DV and CV components, hybrid oscillator-qubit processors enable a powerful new paradigm that offers complementary strengths for quantum control, error correction, computation, and simulation. Working toward the goal of a full-stack system connecting applications to CV-DV hardware, we define and formulate abstract machine models and instruction set architectures. These essential abstractions enable codesign of hardware and software, and resource estimation for exploring the potential of current and future hardware for computational and simulation tasks. Using these abstractions, we present both new and existing examples that illustrate the benefits of hybrid CV-DV processors relative to traditional DV-only hardware in computation as well as quantum simulation of physical models. Examples include algorithms for transferring states between DV and CV systems, performing the quantum Fourier transform, and simulation of lattice gauge theories. Relative to qubit-only hardware, the bosonic degrees of freedom natively available in hybrid architectures can substantially reduce the circuit complexity of simulations for physical models containing bosons. A key technique is the extension of quantum signal processing ideas to CV-DV systems. This work is intended to serve as a timely and comprehensive guide to this relatively unexplored yet promising approach to quantum computation and to provide a road map to guide future development. Starts at 12:00 p.m. ET/9:00 a.m. PT.
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DEC
10
Thursday
Quantum Thursdays Lecture Series
"Scattering processes from quantum simulation algorithms for scalar field theories"
Presented by Nathan Wiebe, Pacific Northwest National Laboratory, University of Toronto
12 pm, Videoconference / Virtual Event
Thursday, December 10, 2026, 12:00 pm
Hosted by: Kai-Mei Fu - C2QA Deputy Director, University of Washington
We provide practical simulation methods for scalar field theories on a quantum computer that yield improved asymptotics as well as concrete gate estimates for the simulation and physical qubit estimates using the surface code. We achieve these improvements through two optimizations. First, we consider a finite volume approach for estimating the elements of the S-matrix. This approach is appropriate in general for 1+1D and for certain low-energy elastic collisions in higher dimensions. Second, we implement our approach using a series of different fault-tolerant simulation algorithms for Hamiltonians formulated both in the field occupation basis and field amplitude basis. Our algorithms are based on either second-order Trotterization or qubitization. The cost of Trotterization in occupation basis scales as ???(?????7?|Ω|3/(??5/2???3/2)) where ?? is the coupling strength, ?? is the occupation cutoff, |Ω| is the volume of the spatial lattice, ?? is the mass of the particles and ?? is the uncertainty in the energy calculation used for the ??-matrix determination. Qubitization in the field basis scales as ???(|Ω|2?(??2?Λ +?????2)/??), where ?? is the cutoff in the field and Λ is a scaled coupling constant. We find in both cases that the bounds suggest physically meaningful simulations can be performed using on the order of 4 ×106 physical qubits and 1012 ??-gates which corresponds to roughly one day on a superconducting quantum computer with surface code and a cycle time of 100 ns. This places the simulation of scalar field theory within striking distance of the gate counts for the best available chemistry simulation results. Starts at 12:00 p.m. ET/9:00 a.m. PT.
