Refined quantum gates for $\Lambda$-type atom-photon hybrid systems

TL;DR

This paper introduces refined protocols for implementing high-efficiency quantum logic gates on hybrid atom-photon systems using reflection geometry, enabling scalable multi-qubit operations with minimal resources.

Contribution

The paper presents novel protocols for controlled-not, Fredkin, and Toffoli gates on hybrid systems, extending to multi-qubit gates with linear optical elements and no auxiliary particles.

Findings

Protocols achieve high efficiency with minimal resources.

Multi-qubit gates scale linearly with the number of qubits.

Single-qubit operations are simplified to photon-only manipulations.

Abstract

High-efficiency quantum information processing is equivalent to the fewest quantum resources and the simplest operations by means of logic qubit gates. Based on the reflection geometry of a single photon interacting with a three-level $\Lambda$-typle atom-cavity system, we present some refined protocols for realizing controlled-not (CNOT), Fredkin, and Toffoli gates on hybrid systems. The first control qubit of our gates is encoded on a flying photon, and the rest qubits are encoded on the atoms in optical cavity. Moreover, these quantum gates can be extended to the optimal synthesis of multi-qubit CNOT, Fredkin and Toffoli gates with O(n) optical elements without auxiliary photons or atoms. Further, the simplest single-qubit operations are applied to the photon only, which make these logic gates experimentally feasible with current technology.