EQC

The "Experimenting with Quantum Computers" project started in January 2019, and is mainly focused on the study of how to program the prototypes of quantum computing systems that are under development, and in particular the IBM prototypes. The project includes the groups of Ferrara, Bari and Pisa. The aim is to consider relevant problems and algorithms both at the general computer science level and more specifically for physics applications. In particular, we want to study how to program such systems to solve, for example, combinatorial problems of non-polynomial computational complexity, such as the satisfiability of a Boolean formula (SAT), the coloring of a graph, the search for a cut of maximum cost in a graph. To solve these problems we will study how to use algorithm schemes such as Grover for unstructured search, and Variational Quantum Eigensolver for the search for the minimum energy state of a spin system. On the plus side of physics, we want to explore the potential of quantum computers to solve computational physics problems which, in an approach based on classical computation, are prohibitively expensive or even impossible. A typical example is that of the Monte Carlo simulation of gauge theories on the finite density and temperature lattice; these theories, in the classical computational approach currently used, in fact present a non-positivity of the action which cannot therefore be associated with a classical probability. The project is interested in the study of simple toy models, compatible with the limited resources and the limited temporal coherence of current quantum systems, which allow a first exploration of this new approach to numerical simulation. Starting from January 2020, the Catania group has also joined the project which intends to develop quantum detectors of low intensity magnetic fields (order 100 nT), with spatial accuracy of 100 nm through silicon crystal vacancies.