Efficient Generation of a Maximally Entangled State by Repeated On- and Off-Resonant Scattering of Ancilla Qubits

TL;DR

This paper presents a robust, efficient scheme for preparing two qubits in a maximally entangled state through repeated scattering of ancilla qubits, achieving perfect efficiency without post-selection.

Contribution

It introduces a novel scattering-based protocol that guarantees convergence to a maximally entangled state from any initial state, with rigorous proof and robustness analysis.

Findings

Achieves 100% success probability in entanglement preparation.

Proves convergence to the singlet state from arbitrary initial states.

Demonstrates robustness against experimental imperfections.

Abstract

A scheme for preparing two fixed non-interacting qubits in a maximally entangled state is presented. By repeating on- and off-resonant scattering of ancilla qubits, the state of the target qubits is driven from an arbitrary initial state into the singlet state with probability 1 (perfect efficiency). Neither the preparation nor the post-selection of the ancilla spin state is required. The convergence from an arbitrary input state to the unique fixed point (mixing property) is proved rigorously, and its robustness is investigated, by scrutinizing the effects of imperfections in the incident wave of the ancilla, such as mistuning to a resonant momentum, imperfect monochromatization, and fluctuation of the incident momentum, as well as detector efficiency.