Gatecount estimates for performing quantum chemistry on small quantum computers
Abstract
As quantum computing technology improves and quantum computers with a small but nontrivial number of N ≥100 qubits appear feasible in the near future the question of possible applications of small quantum computers gains importance. One frequently mentioned application is Feynman's original proposal of simulating quantum systems and, in particular, the electronic structure of molecules and materials. In this paper, we analyze the computational requirements for one of the standard algorithms to perform quantum chemistry on a quantum computer. We focus on the quantum resources required to find the ground state of a molecule twice as large as what current classical computers can solve exactly. We find that while such a problem requires about a 10fold increase in the number of qubits over current technology, the required increase in the number of gates that can be coherently executed is many orders of magnitude larger. This suggests that for quantum computation to become useful for quantum chemistry problems, drastic algorithmic improvements will be needed.
 Publication:

Physical Review A
 Pub Date:
 August 2014
 DOI:
 10.1103/PhysRevA.90.022305
 arXiv:
 arXiv:1312.1695
 Bibcode:
 2014PhRvA..90b2305W
 Keywords:

 03.67.Ac;
 31.15.ae;
 Quantum algorithms protocols and simulations;
 Electronic structure and bonding characteristics;
 Quantum Physics;
 Physics  Chemical Physics
 EPrint:
 15 pages, 8 figures, 3 tables. Added references and clarified key aspects. Accepted for publication in Physical Review A