Robustness of quantum Grover algorithm against decoherence

Yuan Sun

O. V. Zhirov, Dima L. Shepelyansky

Gonzalo Abal, R. Donangelo, Franklin de Lima Marquezino +2 more

Recently several quantum search algorithms based on quantum walks were proposed. Those algorithms differ from Grover's algorithm in many aspects. The goal is to find a marked vertex in a graph faster than classical algorithms. Since the implementation of those new algorithms in quantum computers or in other quantum devices is error-prone, it is important to analyze their robustness under decoherence. In this work we analyze the impact of decoherence on quantum search algorithms implemented on two-dimensional grids and on hypercubes.

Tao Qin, Kelin Gao

We propose a scheme to implement a two-qubit Grover quantum search algorithm. The novelty in the proposal is that the motional state is introduced into the computation and the internal state within a single cold trapped ion. The motional and internal states of the ion are manipulated as two qubits by the laser pulses to accomplish an example of a Grover algorithm based on the two qubits. The composite laser pulses that are applied to implement the Grover algorithm have been designed in detail. The issues concerning measurement and decoherence are discussed.

Ming‐Liang Hu, Heng Fan

Mang Feng

The desired interference required for quantum computing may be modified by wave-function oscillations for the implementation of quantum algorithms [Phys. Rev. Lett. 84, 1615 (2000)]. To diminish such a detrimental effect, we propose a scheme with trapped ion pairs as qubits and apply the scheme to the Grover search. It will be shown that our scheme cannot only carry out a full Grover search, but can also meet the requirement for scalable hot-ion quantum computing. Moreover, the ion-pair qubits in our scheme are more robust against decoherence and the dissipation caused by the environment than single-particle qubits proposed before.