Multi-core Quantum Computers: Analyzing the mapping of quantum algorithms

Abstract

Intermediate scale quantum computers already exist, but they are still far from showing their full computational power as they are limited by the number of qubits and noise. Therefore, a current and relevant challenge is to scale up quantum processors to build a large-scale and fault-tolerant quantum system. One of the most promising approaches for scaling quantum computers is to use a modular or multi-core architecture, in which different quantum chips are connected via quantum and classical links. A crucial aspect in multi-core quantum processor architectures is the communication between cores when qubits need to interact, as these communications are very costly. An approach to reduce these inter-core communications is by optimally mapping the quantum circuit into the quantum hardware. So far, only one mapping algorithm for multi-core quantum processors has been proposed, which is based on the relaxed Overall Extreme Exchange (rOEE) algorithm. In this thesis, we explore and analyze the application of the rOEE for mapping quantum algorithms in this kind of architecture with the aim of identifying possible limitations.