Classiq has unveiled a Fault Tolerance Engine that estimates the physical resources needed to run quantum applications on real, error-prone hardware, the company says. Unlike theoretical calculations, the engine measures resource needs from a concrete, architecture-aware execution plan, revealing what a machine would actually run. This capability accounts for factors including physical qubit requirements, error-correction cycles and the costly T gates essential for fault-tolerant computing.
“Fault tolerance changes the question quantum software has to answer,” says Nir Minerbi, co-founder and CEO of Classiq. “It is no longer enough to create an efficient logical circuit.”
Fault Tolerance Engine Translates Logical Programs to Physical Plans
The Fault Tolerance Engine directly measures the resources needed for quantum computations, moving beyond theoretical calculations to assess physical implementation costs. Unlike estimations based solely on algorithmic complexity, the engine generates a concrete, architecture-aware execution plan before determining physical qubit requirements, error-correction cycles and runtime. This approach accounts for the specific demands of T gates and magic-state resources, both particularly expensive operations within fault-tolerant quantum computing. The engine’s detailed analysis extends to code distance, routing, scheduling, and the accumulation of errors, providing a comprehensive view of implementation costs.
The most efficient logical quantum circuit does not necessarily translate to the most efficient fault-tolerant implementation because physical costs can vary significantly based on factors like T-gate requirements and the amount of fault-tolerant infrastructure needed. Classiq’s platform, built around the Qmod high-level quantum programming language, begins by defining algorithmic intent, then uses its synthesis engine to determine an optimized logical implementation under relevant constraints, according to the company.
The Fault Tolerance Engine then extends this workflow by translating the logical program into the requirements of fault-tolerant execution, optimizing qubit layout and interactions to minimize physical qubit usage, typically the largest single cost in a fault-tolerant computation. Founded in 2020 and headquartered in Tel Aviv, Israel, Classiq has positioned itself as a key player in bridging the gap between quantum algorithms and their physical realization.
The company’s model-first approach, combined with partnerships like the one with C12, addresses the need for scalable quantum hardware and software. The Fault Tolerance Engine is not a standalone development environment but an extension of existing architecture, which separates application intent from low-level implementation. This allows the synthesis technology to explore implementation alternatives and optimize quantum programs under hardware and resource constraints. The engine’s capabilities are relevant to a broad range of stakeholders, from application developers evaluating future workloads to enterprises planning quantum programs and research organizations comparing algorithms and architectures.
It also provides hardware teams with a concrete artifact, a complete fault-tolerant execution plan tied to a specific machine, to facilitate joint roadmap planning. “The gap between an algorithm and its physical realization becomes much larger once quantum error correction is introduced.
Our goal is to give users a way to reason across that gap, while continuing to work at the high level of abstraction where meaningful applications can actually be designed.” The engine’s output goes beyond simple resource estimation. It generates an architecture-aware execution plan for carrying out computations on target hardware. A fault-tolerant computation requires careful consideration of spatial and temporal factors, including the positioning of protected logical qubits, the routing of interactions, the continuous operation of error-correction procedures, and the availability of auxiliary resources.
By integrating these factors, the engine helps users answer critical questions such as the number of physical qubits required, the necessary error-correction cycles, the expected runtime and the main bottlenecks to performance. It also allows for the evaluation of how layout, routing, and scheduling affect the overall computation and what level of protection is needed to achieve a target failure probability.
The launch of the Library, the largest collection of quantum algorithms and applications, also emphasises the company’s dedication to providing developers with the tools they need to explore and implement quantum computing software, the company says. “The Fault Tolerance Engine extends the approach into that layer, so users can work from the application they want to build all the way toward understanding what it will take to implement it reliably,” Minerbi stated.
The platform’s ability to support both the design and optimization of quantum algorithms, as well as the study of their physical feasibility, represents a step toward realizing practical fault-tolerant quantum computing., Classiq reports.
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