The quantum world hosts a rich variety of physics that could enable functionality far beyond what traditional technologies can achieve. By probing and manipulating phenomena that occur at the single particle scale, the emerging field of quantum information science (QIS) aims to create new forms of computing, sensing, and communications that could revolutionize how we process and transmit data. The US recently launched the National Quantum Initiative (NQI) to foster collaboration across multiple government agencies in order to strengthen US leadership in QIS and support the next generation of quantum scientists and engineers.
Despite this potential for tremendous impact, the qubit, or the basic element of any quantum information system, still lags behind in the performance needed to reach these goals. To close this gap in performance, and in support of the NQI, the National Security Agency’s Laboratory for Physical Sciences (LPS) is launching the LPS Qubit Collaboratory (LQC) in partnership with the Army Research Office (ARO).
First described by computer scientist Dr. William Wulf in 1989, a collaboratory is a “center without walls in which the nation’s researchers can perform their research without regard to physical location, interacting with colleagues, accessing instrumentation, sharing data and computational resources, [and] accessing information in digital libraries.” Inspired by this concept, the LQC aims to pursue disruptive research with people, new labs, and collaborations at LPS while creating new workforce programs and training opportunities, both at LPS and nationwide, and build on relationships with universities and organizations to bring together diverse approaches towards advancing qubit and associated technologies.
The Army Research Office and National Security Agency’s Laboratory for Physical Sciences recently launched a new research hub “without walls” that will connect scientists and engineers from across sectors and the nation to explore the limits of quantum information technologies.
“The LQC will combine collaborative research across the country and research experiences at LPS to understand the limits of quantum information technology,” said NSA Acting Research Director Dr. Mark Segal. LPS and ARO will build on years of experience to create an environment that is uniquely suited to tackle the most challenging problems in quantum information research. “ARO and LPS have worked together for 20 years to advance quantum computing research and build the quantum computing community. We take this bold step together to create a new kind of center,” said ARO Director Barton Halpern.
In a broad agency announcement released in April 2021,, ARO and LPS describe early research areas to be pursued via the project—called the LPS Qubit Collaboratory, or LQC—and invite proposals to push forward experimental efforts that make sense for cooperative approaches. “Substantial progress on solving the most difficult and long-term Quantum Information Science & Technology (QIST) research problems that unleash further rapid progress in the field will constitute LQC success,” officials wrote in the BAA.
The mission of the LQC can be captured in three broad goals: 1) pursue disruptive fundamental research and enabling technologies with a focus on qubit development for quantum computing and other applications (such as sensing); 2) grow deep, collaborative partnerships to tackle the most difficult and relevant long-term problems in quantum information science and technology; and 3) build a quantum workforce of tomorrow through research experiences in government at LPS and at LQC partners. The LQC will offer a mechanism for collaborative research between LPS and academia, industry, FFRDCs, and Government Laboratories to advance foundational and transformative research on challenging problems that have hindered progress in quantum information processing and associated technologies.
Proposals for this BAA are set to fall into three categories: Incubator; Collaboratory; and the Quantum Computing Research, or QuaCR fellowship.
Through incubator proposals, LQC aims to connect with single investigators and small research groups that might “have creative solutions and unique skill sets to contribute toward the research topics” listed, the BAA notes, but lack the necessary infrastructure at their home institutions. They could potentially use the LPS’ assets and available collaborations to boost their work. And proposals that unite researchers from across public, private and academic organizations and want to collectively go after longer-term projects around quantum development fall under the Collaboratory category.
The LQC QuaCR fellowship program will award proposals supporting U.S. citizen graduate students and postdoctoral candidates, in hopes to attract them to the emerging field. Fellows would have to spend at least one summer working at LPS, among other requirements.
ARO Program Manager Dr. T.R. Govindan said in the earlier announcement that those involved “want to show that government service as a scientist, engineer, or program manager can be just as, if not more, impactful for the nation than any other quantum career path.”
Substantial progress on solving the most difficult and long-term Quantum Information Science & Technology (QIST) research problems that unleash further rapid progress in the field will constitute LQC success. Examples of such research problems include (but are not limited to): limits of performance due to device design, material selection, and/or control, the exploration of alternative qubit physics (e.g., different approaches to qubit encoding or types of gates) and lowering of barriers to such approaches, advances in materials that improve qubit gate fidelity, reducing the overhead of classical components in quantum information technology and optimizing classical performance, and the exploration of applications of quantum technologies to new domains, officials wrote in the BAA.
LPS Qubit Collaboratory (LQC) thrust on qubit development for quantum computing and sensing
Over the past two decades, researchers have scaled qubits from just a single device to systems with dozens of devices integrated into quantum computer testbeds. But the climb is far from over. As Dr. Charles Tahan, Chief Scientist of LPS and currently on detail to White House’s Office of Science and Technology Policy, points out, “The quantum computers of tomorrow won’t use today’s qubits. We need to continue to work on the hard, long-term problems.”
LQC’s initial “research thrusts”—or technical areas of interest that will be updated periodically—are laid out in the BAA. They involve various aims to improve how qubits perform, advance modern devices and speed up the making mechanisms to introduce people, particularly undergraduate to mid-career scientists, physicists and engineers, to quantum concepts.
1.) Spin qubits, fast.
This research area is interested in democratizing spin qubits. Working spin qubits are hard to fabricate and require significant infrastructure and workforce investments. New materials heterostructures and device fabrication techniques can take decades to master. Viable pathways
to address difficult materials science challenges without starting from scratch have great potential to improve access to the field. Another roadblock is software and control engineering. Dots require many control lines and control signals. Any reduction in control complexity either by simplifying control systems and/or better qubit design would open many research avenues.
Specifically, research proposals are sought that innovatively advance easier methods to characterize and explore the physics of multi-dot systems, ideally in more than one material. The goal is a potential reference system (control hardware, software, and environment) to initialize, control, and readout systems of approximately 10 quantum dots, but with sufficient flexibility to apply to a variety of semiconductor quantum dot qubit and gate approaches. Of particular interest are systems for electrons in silicon and holes in germanium.
Proposers should consider the following questions in formulating their research proposal.
Can the initial evaluation of materials be completed faster before investing heavily in device fabrication? Can a common infrastructure be constructed that would open the field to new researchers interested in qubit measurement and control, but not fabrication and/or growth? Can the control stack be standardized to enable small quantum dot systems to be controlled quickly?
2.) More epitaxy, better qubits?
Materials science for quantum computing has largely focused on a basic assumption: that epitaxial devices are better for quantum computing. Are these assumptions that are valid for conventional devices also valid for quantum information devices? How can the positive or negative implications of various epitaxial (or epitaxial-like) growth paradigms be rapidly determined through device modeling, through device testing, and through material characterization? What are the most promising materials for epitaxial qubits? Which qubit systems can benefit from epitaxial materials and/or does epitaxy enable novel qubit approaches? Improvements in computational methods and understanding of surfaces/interfaces at the microscopic level that will enable these assessments are needed and are of interest to this
3.) Voltage controllable superconducting qubits
This research area is interested in exploring compatibility of superconducting devices that are controllable by baseband voltage pulses. Design and qubit quality implications are of particular interest, as well as compatibility with existing wafer growth facilities at LPS and LQC partners. Further, understanding the fundamental limits of charge noise in superconducting systems is a long-term and presently under-investigated challenge.
4.) Going hot and not looking back
Significant improvements in cooling power and complexity can be gained if qubits did not need to be cooled as much as technically possible using dilution refrigerators. This research area would consider designing qubits and multiple qubit experiments to operate in the range of 350 mK to 2 K. For solid-state, gate-based quantum computing, what experimental systems are most promising and empowered by this capability? What physical systems can be employed as qubits that would be promising in this temperature range? What temperature within this range would be desirable and matched for available refrigerators?
5.) Beyond Moore, Before Shor
Significant effort has been put into the development of ultra-high-quality or precision-grown materials systems for qubits in the quantum computing research community. Examples include ultra-low-loss silicon-germanium heterostructures, atomistic fabrication techniques, and
superconducting circuits for spin and superconducting qubits, respectively. This research area is interested in exploring the potential for these increasingly well-controlled quantum devices and systems for classical computing and enabling device applications such as low-power or ultra-fast computing or electronics and unique approaches to component technology well before the advent of a large-scale quantum computer
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