Objective and Background

Quantum simulation is a rapidly growing field with the potential to revolutionize our understanding and solution of complex problems in physics, chemistry, and materials science. The idea of simulating quantum systems on a quantum computer was first proposed by Richard Feynman in the 1980s as a way to simulate the behaviour of quantum systems that are too complex to be studied using classical computers. Since then, advances in quantum hardware and algorithms have made it possible to simulate increasingly larger and more complex systems, including many-body systems.

In a recent work (https://arxiv.org/abs/2303.06161) we have demonstrated that quantum computers are already mature enough to compute non-trivial properties of quantum systems. Specifically, we focused on the density of states, a fundamental property of many-body systems that plays a central role in quantum statistical mechanics. Through it, one can extract thermodynamic information from a microscopic description of a system, such as the partition function and all finite-temperature equilibrium thermodynamic quantities. The ability to calculate the density of states on a quantum computer opens up a whole new direction in many-body physics, as it allows us to explore the behaviour of complex systems in a way that was previously inaccessible with existing methods. This has the potential to lead to new insights into the behaviour of materials and chemical systems, with implications for fields ranging from energy storage to drug discovery.