Quantum Computing and Control by Optical Manipulation of Molecular Coherences: Towards Scalability.

摘要

Principles of quantum computing using molecular vibronic states and time-frequency resolved coherent anti-stokes Raman scattering (TFRCARS) were demonstrated through, and the execution of standard algorithms were elaborated along with measures of fidelity. These proof-of-principle implementations are on ensembles of molecules in the gas phase, unlikely to be a realistic architecture in practical implementations. We have therefore focused on solid- state implementations of the same, where now the understanding and control of decoherence of systems in intimate contact with their surrounding environment is the key scientific challenge. Very significant progress in this regard has been made in, (a) developing the tools to probe quantum coherence and decoherence of vibronic states in phase space, (b) developing semi-classical methods for the analysis of the mechanics of decoherence, (c) demonstrating mesoscopic coherence ('cat'-states) and complete arrest of decoherence in stationary non-eigenstates prepared by environmentally induced coherence. Also, significant progress has been made in approaching the single molecule limit in TFRCARS implementations - a crucial step in considering scalable quantum computing using the molecular Hilbert space and nonlinear optics.