Multi-QPU quantum algorithms for quantum dynamics simulations

Quantum computers have the potential to perform computational tasks which are impossible to solve on classical computers. One natural application of quantum computing is to use them for predicting how quantum mechanical systems (e.g., models of quantum magnetism or chemical molecules) evolve in time. However, existing quantum computers – so-called noisy intermediate-scale quantum (NISQ) devices – are not yet powerful enough to generally outperform classical computers. Scaling up is possible by connecting multiple quantum processing units (QPUs) together. This approach has a significant drawback: transmitting quantum information from one QPU to the next is necessary but relatively slow. This calls for the design of specialized algorithms that can take advantage of the multi-QPU architecture without straining the communication channels. In this project, we will design and optimize multi-QPU quantum algorithms for simulating the time evolution of quantum mechanical systems. We will benchmark the degree to which quantum mechanical systems can be represented on NISQ devices that are subject to the hardware constraints that arise from the slow inter-QPU communication channel. We will further determine optimized protocols to implement quantum simulations so that errors in the computation are minimized. Ultimately, we will execute these algorithms on available quantum hardware.

Finn Buessen
Faculty Supervisor: 
Dvira Segal
Partner University: