Ab initio molecular properties on a quantum computer: Green’s functions and response functions
Since the information carrier of a programmable quantum computer is a set of qubits that exploits the principle of superposition, essentially parallel algorithms can exist and perform computation for classically formidable problems. Quantum chemistry is believed to be one of the most suitable research fields for quantum computation since its problem setting is quantum mechanical by definition. There exist multiple ab initio approaches to obtain the ground state of an interacting electronic system such as the variational quantum eigensolver (VQE)  and imaginary-time evolution . Apart from which approach is adopted among them, the need for calculation of various physical properties of the target system arises. We proposed recently schemes for the construction of Green’s function  and linear-response functions  of an interacting electronic system by using statistical sampling on a quantum computer. We performed classical simulations of such construction for molecular systems by comparing with the accurate ones based on the full configuration interaction calculations. The details of schemes and the results of simulations will be explained in the talk. Peruzzo et al., Nat. Commun. 5, 4213 (2014).
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