Quantum-Selected Configuration Interaction: Classical Diagonalization of Hamiltonians in Subspaces Selected by Quantum Computers
<p>Quantum computing has opened up a realm of possibilities, especially in the area of simulating and understanding complex quantum systems in areas like quantum chemistry and condensed matter physics. Recent paper by QunaSys describes a promising approach- Quantum-Selected Configuration Interaction (QSCI) algorithm. It offers a novel and more efficient way to find ground-state and excited-state energies in quantum systems. In particular, the new approach circumvents effects of the errors that can spoil the variational nature of VQE: that is, the energy estimated by quantum devices is not guaranteed to give an upper bound on the exact ground-state energy. This is problematic because lowering the resulting energy of VQE does not necessarily mean approaching to the exact ground state. As we will learn QSCI solves this problem and yields results obeying the variational principle. In this blog post, we’ll delve into the key components and advantages of the QSCI algorithm, and how it is paving the way towards useful quantum computing. Below we describe the algorithm in general terms.</p>
<p><a href="https://qunasys.medium.com/quantum-selected-configuration-interaction-classical-diagonalization-of-hamiltonians-in-subspaces-0f9783c58aba"><strong>Website</strong></a></p>