Implementation of quantum gate operations in molecules with weak laser fields.
We numerically propose a way to perform quantum computations by combining an ensemble of molecular states and weak laser pulses. A logical input state is expressed as a superposition state (a wave packet) of molecular states, which is initially prepared by a designed femtosecond laser pulse. The free propagation of the wave packet for a specified time interval leads to the specified change in the relative phases among the molecular basis states, which corresponds to a computational result. The computational results are retrieved by means of quantum interferometry. Numerical tests are implemented in the vibrational states of the B state of I2 employing controlled-NOT gate, and 2 and 3 qubits Fourier transforms. All the steps involved in the computational scheme, i.e., the initial preparation, gate operation, and detection steps, are achieved with extremely high precision.
Teranishi
Yoshiaki
Y
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. tera@mail.tains.tohoku.ac.jp
Ohtsuki
Yukiyoshi
Y
Hosaka
Kouichi
K
Chiba
Hisashi
H
Katsuki
Hiroyuki
H
Ohmori
Kenji
K