IBM | Calculation of Green's functions for the Heisenberg model

Quantum computers currently available are said to be noisy, meaning that they commit errors with a high probability. A contemporary problem is to find applications where, despite their constraints, these noisy machines could surpass the capabilities of classical computing. 

This project tackles a model for simulating quantum materials: the Heisenberg model. The aim is, for a given quantum state, to calculate a function of this state known as Green's function. The main challenge is to prepare this state on the quantum processor, despite the noise to which it may be subject. The approach we have chosen to tackle this problem is a Krylov-type method, where we operate in a reduced subspace of the Hilbert space of the system.