MIT Lincoln Laboratory is making quantum research more accessible through its Superconducting Qubits at Lincoln Laboratory (SQUILL) Foundry. The foundry, sponsored by the Laboratory for Physical Sciences (LPS) Qubit Collaboratory, offers free fabrication capabilities to institutions working on U.S. government-funded research. Superconducting qubits, the building blocks of quantum computers, are complex and expensive. The SQUILL Foundry aims to lower this barrier, enabling more researchers to contribute. Principal investigator Mollie Schwartz and Stanford University Professor David Schuster have praised the foundry’s impact on quantum research.
Quantum Computing: From Theory to Reality
Quantum computing has evolved from a theoretical concept to a global industry over the past three decades. It is inching closer to becoming a technology that could solve problems too complex for even the most powerful supercomputers. The MIT Lincoln Laboratory is not only conducting research in this field. Still, it is also making quantum research accessible to a broader community through its Superconducting Qubits at Lincoln Laboratory (SQUILL) Foundry.
Quantum bits (qubits) are the building blocks of quantum computers, similar to how transistors are for classical computers. One of the most promising ways of creating a qubit is through superconducting qubits, which are generated using circuits made of superconducting elements. These qubits are fabricated using techniques similar to conventional microelectronics fabrication, such as depositing and etching thin metal films on a substrate. They are then operated at near-absolute zero temperatures to form “artificial atoms.”
The Challenges of Superconducting Qubits
Despite the promise of quantum computing, realizing its potential requires fundamental research and experimentation using qubits. However, superconducting qubits are difficult to build, and a significant barrier for scientists wishing to pursue this research is the expensive tooling and specialized processes needed to fabricate the circuits. Other groups have also pointed out the benefits of superconducting circuits, such as Chad Rigetti, the founder of the Quantum Computing company named: Rigetti. IBM in its systems have recently exceeded 433 superconducting qubits in their IBM Quantum systems and are looking like they are on target to hit over 1,000 by 2024. Superconducting
Sponsored by the Laboratory for Physical Sciences (LPS) Qubit Collaboratory, a National Quantum Initiative-funded centre, the program makes Lincoln Laboratory’s advanced fabrication capabilities available at no cost to institutions working on U.S. government-funded research. Researchers can submit quantum circuit designs for fabrication, and the completed circuits are returned to advance scientific inquiry in their home facilities.
The SQUILL Foundry: Democratizing Access to Qubit Fabrication
The SQUILL Foundry aims to democratize access to robust, reliable qubit fabrication, significantly lowering the barrier to entry in superconducting qubits. The goal is to enable researchers whose core focus is not on materials and fabrication to concentrate on driving progress in the areas of superconducting qubit research that they are most interested in.
The foundry program has allowed quantum labs to consider experiments they could not have attempted before due to the complexity of nanofabrication required. It has also enabled younger students to design and measure complex quantum circuits much faster than they could in the past.
Superconducting Qubits: A Diverse Family of Quantum Circuits
One of the main advantages of superconducting qubits is their designability. Their dynamics and interactions are not dictated by nature, like those of a physical atom, but rather are designed by combining capacitors, inductors, and Josephson junctions (a type of superconducting switch) in creative ways to create the energy landscape of interest. This designability makes superconducting qubits a diverse family of quantum circuits, each with unique looks and behaviours.
Advancing the state of the art in superconducting qubit hardware requires knowledge across various disciplines, including materials, fabrication, circuit design and simulation, packaging, cryogenics, low-noise measurement, hardware-software interfacing, and quantum compilation. As understanding of materials and processes has advanced, fabricating the highest-quality qubits increasingly relies on expensive fabrication equipment and countless hours of process development and sustainment.
The Future of the SQUILL Foundry
Building on the success of the pilot, the SQUILL Foundry is transitioning to a full four-year project, opening the doors to the broader research community in a by-application access model that is available to any sponsor-approved superconducting qubit research project supported by a U.S. government grant.
The full-scale foundry will roll out more advanced capabilities, including compact arrays of Josephson junctions and flip-chip integration (a compact method of connecting multiple circuits), to enable more advanced qubit designs. Additional qualifications will be developed with user input and made available as the SQUILL Foundry program proceeds to ensure that the foundry continues to meet the community’s evolving needs.
More than 20 research groups are poised to leverage the foundry as the access model expands, and this number is expected to grow over time. The aim is to work with schools that do not have the resources to purchase and maintain fabrication equipment, thereby lowering the barrier to entry and enabling more students to participate in superconducting qubit research.
“Democratizing access to robust, reliable qubit fabrication dramatically lowers the barrier to entry in superconducting qubits,”
Mollie Schwartz, the principal investigator of the project and a leader of superconducting qubit research at Lincoln Laboratory.
“It has allowed my younger students to design and measure complex quantum circuits much faster than they could in the past.”
Stanford University Professor David Schuster
“It has become increasingly challenging for individual organizations to maintain this full stack of expertise, particularly as circuits become more complex to design, fabricate, and measure,” Schwartz says.
Mollie Schwartz, the principal investigator of the project and a leader of superconducting qubit research at Lincoln Laboratory.
“There is certainly a learning curve when you are used to fabricating devices in-house, but the support and information provided by the foundry to aid users in the process has been phenomenal,”
Professor Machiel Blok, who runs a research group at the University of Rochester.
Professor Kater Murch from Washington University in St. Louis, Missouri, says, “We’re just finalizing initial results from our first projects, but the work we’ve done in the lab to get our devices to work puts us several years ahead of where we would have been without the program.”
“Qubit chips from the Lincoln Laboratory foundry effort have already helped nine research groups across the country realize their ideas and accelerate their research,” says Charles Tahan, the director of the LPS Qubit Collaboratory.
“There are incredibly talented and creative students across the country who cannot currently participate in superconducting qubit hardware research, but whose discoveries might change the way we think about this technology. Lowering the barrier to entry will enable some of these institutions to stand up superconducting qubit research groups, which will help expose more students to quantum research and expand our workforce as the industry grows,” Schwartz says.
Summary
MIT Lincoln Laboratory’s Superconducting Qubits at Lincoln Laboratory (SQUILL) Foundry makes quantum research more accessible by providing free fabrication of superconducting qubits, the building blocks of quantum computers, for institutions conducting U.S. government-funded research. The initiative aims to lower the barrier to entry in superconducting qubits research, enabling more researchers to contribute to the advancement of quantum computing technology.
- Quantum computing has evolved significantly over the past three decades, with MIT Lincoln Laboratory leading the way in research and accessibility through its Superconducting Qubits at Lincoln Laboratory (SQUILL) Foundry.
- Quantum bits (qubits) are the building blocks of quantum computers, with superconducting qubits being one of the most promising types. They are created using circuits made from superconducting elements and operated at near-absolute zero temperatures.
- The SQUILL Foundry, sponsored by the Laboratory for Physical Sciences (LPS) Qubit Collaboratory, offers free access to Lincoln Laboratory’s fabrication capabilities for institutions conducting U.S. government-funded research.
- Mollie Schwartz, the principal investigator of the project, aims to lower the barrier to entry in superconducting qubits research.
- Stanford University Professor David Schuster praises the SQUILL Foundry for enabling his quantum lab to undertake complex experiments.
- The SQUILL Foundry ran as a pilot from July 2021 to February 2023, with users submitting custom designs for fabrication. The program resulted in 13 presentations and four scientific papers.
- The SQUILL Foundry is transitioning to a full four-year project, opening access to the broader research community. Over 20 research groups are expected to leverage the foundry as the access model expands.
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