The Superconducting Quantum Materials and Systems, or SQMS, Center will advance both quantum science and technology.
SQMS research will focus on optimizing the lifetime of quantum states, known as coherence time, which is the length of time that a qubit, the basic element of a quantum computer, can effectively process information. Understanding and mitigating the physical processes that limit performance of superconducting qubits is critical to realizing next-generation quantum computers and sensors.
The center will build a quantum computer at Fermilab and develop new quantum sensors based on superconducting technology. With unprecedented coherence time and all-to-all qubit connectivity, it will be a beyond-state-of-the-art quantum computer. The new quantum sensors could lead to the discovery of the nature of dark matter and other elusive subatomic particles.
One of the center’s main strengths comes from Fermilab’s expertise in developing and building complex particle accelerators based on technologies such as superconducting radio-frequency devices and cryogenics, as well as the world-leading coherence times already achieved in superconducting cavities. The SQMS Center will leverage this expertise and that of its partners to engineer multiqubit quantum processors based on state-of-the-art qubits and related superconducting technologies.
SQMS researchers will focus on the technological challenges of both 2-D (planar transmon qubits) and 3-D (superconducting radio-frequency cavities) superconducting devices and their related quantum computing and sensing schemes. These devices are already a technical reality.
In particular, materials science experts will work in understanding and mitigating the key limiting mechanisms of coherence in superconducting radio-frequency cavities and qubits in the quantum regime. Researchers expect to achieve at least an order-of-magnitude improvement in current device coherence times in the quantum regime, which corresponds to a goal of up to tens of seconds in superconducting cavities and up to milliseconds in superconducting 2-D transmons.
An increased qubit’s coherence time allows performing a greater number of operations, called the depth, and also affects the error rate, or fidelity. In fact, each qubit operation, called time step or gate, takes some time to perform. The center plans to achieve high-depth, high-fidelity circuits in quantum computing.
|Processor metrics||Leading systems||Center prototypes
|Center device goals
|Number of qubits||53||128||>100||256||>200|
|Connectivity graph (qubit:neighbors)||1:4||1:3||1:10||1:3||1:200|
|Qubit T1 lifetime, μs (median)||70||200||400,000||400||1,000,000|
|Gate time, ns (median)||20||50||2000||40||100|
|Coherence/gate time ratio||1,000||4,000||20,000||10,000||10,000,000|
|Single qubit gate fidelity (%)||99.85||99.6||99.5||99.95||99.95|
|Two qubit gate fidelity (%)||99.65||99.2||99.5||99.9%||99.95|
|Achievable circuit depth (1/error)||300||100||200||1,000||2,000|
At the same time, researchers will pursue device integration and quantum controls development for 2-D and 3-D superconducting architecture. They will ultimately build quantum computer prototypes based on the two architectures.
Center researchers also plan to design, build and deploy a 2-meter-wide dilution fridge to host both the 2-D and 3-D quantum processors and a large number of qubits. The largest in the world, the fridge will enable new quantum simulation for science applications and will be made available to computing researchers via HEPCloud.
Quantum sensing of elusive particles is currently limited by the ability to store and detect single microwave photons, and it depends directly on quantum devices’ coherence. Center scientists will make use of the SQMS quantum technologies advancements for physics applications. They will design and deploy sophisticated quantum devices and control techniques, capable of improving current detection sensitivities up to orders of magnitude, with consequent increased discovery potentials.
In quantum communication, the SQMS Center will deploy high-coherence devices with seconds of coherence time for microwave photons. This advance enables the development of quantum memories, a key component of long-range quantum communication systems. SQMS researchers plan to demonstrate microwave-to-microwave transfer of entangled states between 3-D quantum systems.