Physical implementation of quantum cellular automaton in a diatomic molecule

量子セルオートマトンの二原子分子への物理的実装

松岡 雷士; 横山 啓一  

Matsuoka, Leo; Yokoyama, Keiichi

We propose an approximate physical implementation of non-coined discrete-time quantum walk (DTQW), which is a class of quantum cellular automata. We regard a molecular rotational state as a node of the quantum walk, and implement unitary operations by pure rotational transitions induced with an optical frequency comb, which is a train of phase-locked pulses of terahertz wave. The analogy between the non-coined DTQW and the molecular rotational dynamics in such an electric field is analytically shown. Numerical simulations have elucidated the relation between the number of pulses in the pulse train and the accuracy of the unitary operations in the non-coined DTQW.