The Defense Advanced Research Projects Agency is looking for companies to build the hardware and software quantum computers need to communicate and work together.
Most quantum computers are standalone systems and the connections that exist rely on quantum teleportation, which has limitations and introduces errors.
DARPA is proposing a multiple award contract to be called HARQ, for Heterogeneous Architectures for Quantum.
The idea is that there are multiple types of quantum computers that rely on different qubit technologies such as superconducting qubits or photonic qubits. Quantum computers can also have different types of processors and different quantum models.
Building large quantum computers with more than 1,000 logical qubits is prohibitively expensive. Relying on a homogeneous qubit infrastructure limits the types of problems a quantum computer can work on, according to solicitation documents.
Each style of quantum computer has strengths and weaknesses. Superconducting qubits are fast but noisy in one example, while trapped ion qubits are more accurate but slower in another. DARPA’s goal is to find ways for them to work together and leverage the different strengths and compensate for the limitations.
The solicitation compares it to how today’s IT infrastructure works:
“The power of modern-day systems in varied exemplars—such as supercomputers, smartphones, and radars—directly trace to the ability to select the best performing components for every function and to quickly and efficiently move data between them in both hardware and software,” the solicitation states.
DARPA says that if the hardware and software can be developed to get multiple quantum computers to work together, users can get more computing power more quickly.
Software is needed to optimize across interfaces using different qubit resources. Hardware is needed to create the connections between heterogeneous qubit platforms, according to solicitation documents.
The solicitation documents talk about the need for a “quantum shared backbone,” which would be akin to how networks connect different types of computers in a data center. The hardware portion is particularly focused on this.
A “quantum shared backbone will provide the hardware basis to combine diverse quantum computer modules in future data-center-scale systems,” the solicitation states.
The HARQ contract will include a phase one period of 24 months. Individual projects will be capped at $2 million. If approved, a nine-month “scale up” period will follow and be worth up to $650,000.
Proposals are due Oct. 14 and DARPA expects awards by Feb. 1, 2026.