Integrating Quantum Processing Units with Supercomputers

The scale of electronic structure calculations feasible on current or near-term quantum hardware is constrained by several inherent limitations, including coherence time, qubit count and connectivity, and device noise. All these limitations taken together severely impact the number of qubits that may be put to work constructively for chemical applications. While we have access to quantum computing devices up to and exceeding 100 qubits, only a fraction of these can be utilized effectively. However, if these resources are aimed at a key subcomponent of a molecular system they can still be of significant value. This fosters the integration of conventional HPC resources with quantum processing units to address problems of scientific interest in which only a key sub-component of the system is analysed on the quantum device.