Fermionic models with superconducting circuits Urtzi Las Heras, Laura García-Álvarez, Antonio Mezzacapo, Enrique Solano and Lucas Lamata EPJ Quantum Technol., 2 1 (2015) 8 Published online: 24 March 2015 DOI: 10.1140/epjqt/s40507-015-0021-5