One of the key applications for quantum computers will be the simulation of
other quantum systems that arise in chemistry, materials science, etc, in order
to accelerate the process of discovery. It is important to ask: Can this be
achieved using near future quantum processors, of modest size and under
imperfect control, or must it await the more distant era of large-scale
fault-tolerant quantum computing? Here we propose a variational method
involving closely integrated classical and quantum coprocessors. We presume
that all operations in the quantum coprocessor are prone to error. The impact
of such errors is minimised by boosting them artificially and then
extrapolating to the zero-error case. In comparison to a more conventional
optimised Trotterisation technique, we find that our protocol is efficient and
appears to be fundamentally more robust against error accumulation.Comment: 13 pages, 5 figures; typos fixed and small update