EPJ Quantum Technol. (2016) 3: 11
https://doi.org/10.1140/epjqt/s40507-016-0049-1

Research

Few-qubit quantum-classical simulation of strongly correlated lattice fermions

¹ Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
² Department of Physical Chemistry, University of the Basque Country, Apartado 644, Bilbao, 48080, Spain
³ Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, UK
⁴ Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
⁵ IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, Bilbao, 48013, Spain
⁶ Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore, 117543, Singapore

^* e-mail: j.kreula1@physics.ox.ac.uk

Received: 15 June 2016
Accepted: 23 July 2016
Published online: 8 August 2016

Abstract

We study a proof-of-principle example of the recently proposed hybrid quantum-classical simulation of strongly correlated fermion models in the thermodynamic limit. In a ‘two-site’ dynamical mean-field theory (DMFT) approach we reduce the Hubbard model to an effective impurity model subject to self-consistency conditions. The resulting minimal two-site representation of the non-linear hybrid setup involves four qubits implementing the impurity problem, plus an ancilla qubit on which all measurements are performed. We outline a possible implementation with superconducting circuits feasible with near-future technology.