The theory of variational hybrid quantum-classical algorithms

Many quantum algorithms have daunting resource requirements when compared to what is available today. To address this discrepancy, a quantum-classical hybrid optimization scheme known as 'the quantum variational eigensolver' was developed (Peruzzo et al 2014 Nat. Commun. 5 4213) with the philosophy that even minimal quantum resources could be made useful when used in conjunction with classical routines. In this work we extend the general theory of this algorithm and suggest algorithmic improvements for practical implementations. Specifically, we develop a variational adiabatic ansatz and explore unitary coupled cluster where we establish a connection from second order unitary coupled cluster to universal gate…

• AF
  Air Force Office of Scientific Research

  Award: FA9550-12-1-0046
• AR
  Army Research Office

  Award: W911NF-15-1-0256
• LB
  Lawrence Berkeley National Laboratory
• OO
  Office of Naval Research Global

  Award: N00014-16-1-2008