Quantum Enhanced and Verified Exascale Computing - QEVEC

Given the advancing capabilities of computing hardware, we need to develop capabilities to extract its potential fully.
This is made challenging by various types of specialist computing hardware, such as GPUs (graphical processing units), or quantum computers.
Combining different types of computing hardware most productively to solve complex problems is crucial for the next generation of high performance computing that will attain exascale processing speeds (more than 10^18 operations per second).
QEVEC - quantum enhanced and verified exascale computing - contributes to this development by focusing on how to add quantum computers as co-processors to conventional high performance computers (HPC).

Early quantum computers will be much smaller -- in terms of the amount of classical data they can process in one go -- than current HPC. But the processing power on that data can be much faster due to their quantum properties of superposition and coherence.
The most promising way to use them is thus to accelerate those parts of the computations that are slow for HPC.
This requires detailed study of the algorithms, both quantum and classical, which QEVEC will do for two specific applications areas, fluids simulations and materials simulations.

Fluids simulations require immense computing power to solve the nonlinear differential equations, often in complex geometries and with mixtures of several fluids with different properties. There are a range of algorithms that can do this, and they can also have wider applications
as nonlinear differential equation solvers. Important applications range through weather forecasting, fluid flows in manufacturing processes, plasma simulations for fusion reactors and stars.

Materials simulations come directly up against the difficulty of simulating quantum systems with classical computers. Quantum systems have a much larger state space than classical systems, which requires a huge amount of memory on classical computers. A quantum computer is thus a natural choice to try to improve performance. There are already many groups studying variational quantum algorithms for this; QEVEC will focus on more advanced methods for simulating solid solutions (metal alloys and other materials composed of two compounds that individually and when combined adopt the same crystal structure), and the basic electronic structure calculations that underpin all first principles biomolecular, chemical and materials simulations.

It is necessary to check all computer calculations at some level, to know how well we can trust them to be correct. Quantum computers need some extra techniques to accomplish this checking, so QEVEC will also develop quantum verification methods for the fluids and materials simulations applications.

To ensure the results from the research carried out by the QEVEC team are widely available for the scientific computing community to benefit from, QEVEC will engage widely with other ExCALIBUR project teams to share their knowledge, and learn from the other projects.