Qarakal’s Pangaea Architecture Applies Classical Computing Lessons to Quantum Systems

Quantum computing research is advancing across error correction, infrastructure, software, and algorithms. As the field moves toward useful, fault-tolerant systems, architecture is becoming an increasingly important focus.

Recent examples include D-Wave’s dual-rail superconducting architecture and QuiX Quantum’s Dedalo architecture for fault-tolerant photonic systems, including its Carina commercial system.

Nadav Katz, co-founder and chief technology officer of Qarakal Quantum, an Israeli startup founded in 2024, says this attention to architecture reflects greater maturity in the field. In his view, quantum computers must be treated as complete computing systems rather than collections of qubits that are programmed only after the hardware has been assembled.

Applying classical computing principles

Architecture could help move quantum computing beyond research laboratories, vendor facilities, and cloud environments into commercial data centers. The objective is to create modular and scalable quantum systems that can operate alongside classical enterprise computers and supercomputers.

Katz compares this transition with the development of classical computing. Early theoretical models treated computers as collections of bits, but practical systems depended on specialization and communication between components. The Von Neumann architecture provided that structure and remains the foundation of most classical computers decades later.

Qarakal is applying a similar approach to superconducting quantum systems. Its recently announced Pangaea architecture is part of a broader effort to support specialized components, heterogeneous code, and modular functionality. A central element is the quantum bus, which acts as a communication bridge between modules and logical qubits.

In classical systems, modularity and scalability became possible when processors, memory, storage, and peripherals could communicate through standardized interfaces such as motherboards, backplanes, and buses. Qarakal argues that quantum systems now require comparable communication structures.

The quantum bus

The quantum bus is designed to enable fault-tolerant logical operations between logical qubits that use different error-correction codes and reside in different types of modules. It also removes the requirement that logical qubits be physically adjacent, allowing systems to scale through more than simply adding qubits.

Qarakal executives describe current quantum systems as complex monoliths that depend on local connectivity and physical adjacency. They argue that this approach increases cost and limits scalability because qubits are replicated within a single layout, requiring each qubit to support multiple functions. Computation, communication, and error correction therefore remain tightly coupled, preventing individual components from scaling independently.

The quantum bus is intended to provide a universal interface for quantum information. Qubits do not need to be adjacent, and the bus can accommodate the error-correction method used by each qubit without requiring all qubits to share the same code.

Sheir Yarkoni, Qarakal’s director of quantum software, says superconducting quantum systems require selecting suitable error-correction codes. Some codes provide high encoding rates and use relatively few physical qubits per logical qubit, but require greater physical connectivity and more operations. Other codes, including planar codes, are simpler to operate and offer more scalable logic, but require more physical qubits because they are two-dimensional.

The quantum bus is intended to reduce the need to choose a single code for the entire system. For example, one module could provide dense memory with slower operations, while another could provide faster operations with less memory. This resembles the division between storage and RAM in classical computers.

The broader goal is to combine specialized components into a unified system whose capabilities exceed those of its individual parts. Qarakal describes this approach in terms of modularity, composability, and communication, adapting principles associated with classical computing to quantum hardware.

Claimed efficiency benefits

Qarakal says the Pangaea architecture requires one-tenth of the physical qubits used by other approaches. According to Katz, this could reduce infrastructure requirements, including wiring, energy consumption, and noise.

The quantum bus is also intended to slow the accumulation of errors. As a result, the logical qubits required to store quantum information could be smaller.

Katz says that in conventional monolithic architectures, much of the qubit capacity is used to move information around. This creates overhead, reduces the error threshold, and makes fault tolerance more difficult to achieve. By enabling more logical operations from the available qubits, the Pangaea design is intended to improve efficiency and reach fault tolerance more quickly.

Yarkoni similarly says that slower error accumulation could reduce the size of the logical qubits needed to store information in a quantum computer.

Qarakal’s roadmap

Pangaea and the quantum bus form part of a three-step Qarakal roadmap. The first stage, planned for this year, focuses on integrating components and capabilities. System deployments are targeted for 2028, followed by system expansion in 2030.