Simulations of quantum computation with a molecular ion

The capabilities of a new system for coherent control-intense terahertz light pulses acting on trapped, gas phase D₃O⁺ molecules-are investigated using realistic molecular and pulse parameters. Computer simulations show that a set of three shaped pulses can be used to perform four level (two qubit) quantum computational gates on the inversion-rotation energy levels and read-out the result using degenerate four-wave mixing. Two pulse shaping techniques are employed, one directly shaping a terahertz pulse, and another shaping a visible laser pulse that is rectified by a terahertz antenna. Both are found to be effective for control. Methods for initializing the inversion-rotation wavepacket, making the pulse robust against power variations, maximizing its fidelity to a unitary gate transformation and addressing limitations of energy level connectivity are discussed.