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.
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. tera@mail.tains.tohoku.ac.jp
Yoshiaki
Y
Teranishi
Yukiyoshi
Y
Ohtsuki
Kouichi
K
Hosaka
Hisashi
H
Chiba
Hiroyuki
H
Katsuki
Kenji
K
Ohmori