SEEQC, a digital quantum computing company, has introduced a new family of high-speed, energy-efficient Single Flux Quantum (SFQ) digital chips. These chips can run all a quantum computer’s core qubit controller functions at the same cryogenic temperature as the qubits and are fully integrated with them. This is crucial in building scalable, error-corrected quantum computers and data centers.
The Single Flux Quantum (SFQ) logic used in SEEQC‘s digital chip technology is energy-efficient and superconducting, operating at up to 40 GHz speeds. It is used to implement classical qubit control, measurement, multiplexing, and data processing. Compared to conventional, complementary metal-oxide semiconductor (CMOS) or CryoCMOS chips, SEEQC‘s SFQ circuits require less energy and produce less heat, making them ideal for use in close proximity to the qubit chips at temperatures as low as 20 milliKelvin.
This is achieved through integrated multi-chip modules, with active SFQ circuits communicating wirelessly and being compatible with all superconducting qubit types, including fluxonium qubits and other qubit modalities like spin qubits.
Integration of Multi-Chip Modules
SEEQC’s multi-chip module architecture, low power consumption, and high-speed operation allow for implementing hardware-efficient digital control, readout, and fast-processing qubit data necessary for fast, low latency, scalable quantum computing. With this technology, SEEQC hopes to contribute to developing practical quantum computing solutions.
SEEQC’s superconducting SFQ circuits are low-energy and have reduced heat dissipation, making them ideal for implementing classical qubit control, measurement, multiplexing, and data processing. SEEQC’s active multi-chip module architecture reduces system latency and complexity by eliminating the need for expensive room-temperature electronics interconnected to the qubit chips.
By integrating all the necessary components onto the SFQ classical chips and qubit chips within multi-chip modules, SEEQC’s technology significantly reduces data processing latency and transfer rates between chips. This will allow for much faster and higher quality qubit readout and reset compared to existing technology, which is crucial for both current applications and fault-tolerant functions.
SEEQC Utilizes Multiplexing Circuits
SEEQC’s quantum computing architecture addresses a key challenge in quantum systems by incorporating digital multiplexing, which sends multiple signals over a single line. This reduces cost and complexity, particularly for large-scale quantum systems in data centers.
Existing quantum computers require up to three cables per qubit, carrying sensitive analog signals, which limits the ability for high-ratio multiplexing in large-scale systems. Millions of cables will be needed for large-scale quantum computers, generating heat that must be dissipated through all stages of a dilution refrigerator. SEEQC’s multiplexing circuits reduce the cables required and the heat generated, enabling more efficient and scalable quantum computing.
SEEQC has tested its digital multiplexing technology, which enables the control of an 8-qubit module with only two wires, and is currently working on versions that can control up to 64 qubits. This technology significantly reduces the capital costs and simplifies the underlying complexity of a quantum computer compared to existing quantum computers, which require up to three cables per qubit.
“Instead of trying to scale quantum computing systems based on existing prototype designs, we decided to start from scratch developing a wholly new architecture based on Single Flux Quantum chips that will enable us to build the class of quantum computer necessary for fault-tolerant quantum computers. Only by incorporating all functionality within high-performance chips will we be able to scale energy efficient quantum systems to data center requirements.”
Dr. Oleg Mukhanov, SEEQC’s CTO and co-founder
SEEQC operates a multilayer superconductive chip foundry and testing center in Elmsford, NY, where they produce their proprietary digital SFQ chips. These chips can operate at cryogenic temperatures ranging from milliKelvin to 4 Kelvin and can control a quantum computer’s core qubit functions.
SEEQC’s foundry is equipped to produce high-complexity superconductive chips and is one of the most advanced commercial chip foundries for full-stack quantum computing chips globally. SEEQC also produces superconductive chips for the DOE, NASA, DOD, and other commercial and academic teams.
SEEQC System Red, a Full-Stack Quantum Computing System
SEEQC has unveiled its first-generation reference class quantum computer system called SEEQC System Red, which is designed to benchmark the performance and capabilities of its new SFQ chips. The system mimics current-generation superconductor quantum computing systems with conventional room temperature analog control and readout, directly allowing the company to compare with its digital SFQ chip-based next-generation quantum computer.
SEEQC Red has achieved average 2-qubit gate speeds of 39ns and average gate fidelities of 98.4%, among the best publicly available quantum systems operating over the cloud.
“When compared to the universal quantum computing systems available over the cloud, our system shows four times lower error rates over competitive systems. SEEQC Red offers the fastest native two-qubit gates over any system available on publicly available quantum cloud services. While other systems focus on larger numbers of qubits, SEEQC’s system is focused on quality and speed. It has achieved gate speeds up to 10 times faster than competitors, all while offering gate fidelities competitive to the most advanced systems available on currently available quantum cloud platforms.”
Matthew Hutchings, co-founder, and chief product officer at SEEQC
“To be useful, a quantum computing hardware benchmark metric has to be a function of scale, quality, and speed. It’s not easy to get all three. That’s why, while the number of qubits in systems keeps going up every year, the most significant results in the field are typically being run on small qubit systems, often 10 or fewer, that have high-quality qubits and fast gate speeds.”
Matt Langione, partner at Boston Consulting Group
“SEEQC’s mission is to deliver scalable, energy-efficient quantum computing for data centers and our approach is through the digital chip-scale integration of key functions like readout, control, multiplexing, error correction, and classical data processing. The two major technology advancements we’ve announced today represent important progress in this mission across the entire quantum computing industry.
John Levy, co-founder, and CEO at SEEQC.
“Through the balance of 2023, we look forward to replacing conventional room temperature electronics with our digital SFQ chips in our next generation SEEQC quantum computers which will also be a major step in our work towards achieving scalable, energy-efficient quantum systems capable of supporting chip-based error correction.
John Levy, co-founder, and CEO at SEEQC.
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