Quantum gate operations using midinfrared binary shaped pulses on the rovibrational states of carbon monoxide

Abstract

Frequency domain shaped binary laser pulses were optimized to perform 2 qubit quantum gate operations in (12)C(16)O. The qubit rovibrational state representation was chosen so that all gate operations consisted of one-photon transitions. The amplitude and phase varied binary pulses were determined using a genetic algorithm optimization routine. Binary pulses have two possible amplitudes, 0 or 1, and two phases, 0 or pi, for each frequency component of the pulse. Binary pulses are the simplest to shape experimentally and provide a minimum fidelity limit for amplitude and phase shaped pulses. With the current choice of qubit representation and using optimized binary pulses, fidelities of 0.80 and as high as 0.97 were achieved for the controlled-NOT and alternative controlled-NOT quantum gates. This indicates that with a judicious choice of qubits, most of the required control can be obtained with a binary pulse. Limited control was observed for 2 qubit NOT and Hadamard gates due to the need to control multiple excitations. The current choice of qubit representation produces pulses with decreased energies and superior fidelities when compared with rovibrational qubit representations consisting of two-photon transitions. The choice of input pulse energy is important and applying pulses of increased energy does not necessarily lead to a better fidelity.

The operations of quantum logic gates with pure and mixed initial states

“…[15][16][17][18][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] The Deutsch-Jozsa algorithm is one of the elementary algorithms in quantum computation. This algorithm was simulated theoretically using vibrational states of acetylene 18 and electronic excited states of iodine.…”

Dynamical entanglement of stretching–stretching and stretching–bending vibrations in SO2

“…SO 2 is one typical normal mode molecule, in which the coupling between different vibrational modes is strong. The strong coupling is critical for the quantum parallelism computation, for example, the strong coupling was found to play an important role in the CNOT (Controlled‐NOT) quantum logic gate . However, some investigations also found that the coupling could induce the decrease of fidelity of quantum gates, as the coupling between the qubit system and the remaining vibrational mode is one important resource of decoherence .…”

Effect of diatomic molecular properties on binary laser pulse optimizations of quantum gate operations

“…11 The many theoretical contributions include, (i) studying molecular systems: modes of acetylene, 6,12,13 ammonia, 14,15 and thiophosgene, 16 vibrational/ro-vibrational excitaa) Electronic mail: alex.brown@ualberta.ca. tions within diatomics, [17][18][19][20][21][22][23][24][25] and of dipole-dipole coupled diatomics, 26 and (ii) investigating experimental issues. 10,27,28 Many of the theoretical studies were based on iterative optimal control theory 29 (OCT) and the resulting pulses were inaccessible to present experiments, e.g., shaped in both the mid-IR and microwave frequency regimes.…”