Hybrid Quantum Architecture for Control-Flow Program Execution
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Solution Overview
Problem
Existing quantum computing frameworks fail to accommodate complex quantum algorithms requiring control flows, such as conditional branching and looping, due to their sequential nature, limiting the execution of algorithms like quantum error correction and measurement-based computing.
Innovation Solution
A hybrid quantum-classical computing system that compiles and executes general quantum programs, optimizing intermediate code to identify and execute subsets on either quantum or classical devices, utilizing a classical computer to manage control flows and quantum circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If quantum algorithms are executed using sequential quantum gates in a quantum circuit, then the execution is simple and well-defined, but complex quantum algorithms requiring control flows (conditional branching, looping) cannot be executed
Solution Approach 1:
A classical controller is introduced as an intermediary component that receives quantum measurement results and sends control signals to the quantum processor. This mediator enables conditional branching and looping control flows, allowing complex quantum algorithms to be executed while maintaining the simplicity of sequential gate execution on the quantum device.
2Adaptability or versatility
If a hybrid quantum-classical system is used to enable control flows, then algorithm versatility is improved, but system complexity increases
Solution Approach 1:
The computing system is segmented into distinct functional components: a classical controller for managing control flows and coordination, and a quantum processor for executing quantum gates. This segmentation allows each component to be optimized independently, reducing overall system complexity while enabling versatile algorithm execution.
Solution Approach 2:
The classical controller serves multiple functions: receiving quantum results, generating control signals, managing measurement timing, and coordinating between quantum and classical components. This multi-functionality reduces the need for separate dedicated components, thereby reducing system complexity while maintaining high versatility.
3Productivity
If quantum algorithms are executed sequentially on quantum processors, then the quantum hardware is utilized efficiently, but the execution time for complex algorithms with control flows increases
Solution Approach 1:
The classical controller pre-calculates and prepares control signals based on expected quantum measurement outcomes before the quantum execution completes. This preliminary action reduces coordination time during actual execution, as the control signals are ready to be sent immediately when quantum results become available, thereby reducing overall execution time despite the hybrid architecture.
Data Source
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AI summary
A computer system, designed according to a particular architecture, compiles and execute a general quantum program. Computer systems designed in accordance with the architecture are suitable for use with a variety of programming languages and a variety of hardware backends. The architecture includes a classical computer and a quantum device (which may be remote from the local computer) which includes both classical execution units and a quantum processing unit (QPU).