Realizing an $n$-target-qubit controlled phase gate in cavity QED: An approach without classical pulses

TL;DR

This paper proposes a fast, efficient method to implement an n-target-qubit controlled phase gate in cavity QED without classical pulses, scaling as √n and applicable to various physical systems.

Contribution

It introduces a pulse-free, scalable approach for multiqubit controlled phase gates with minimal steps, applicable across multiple quantum platforms.

Findings

Gate operation time scales as √n

Only three operational steps needed

Applicable to various physical systems

Abstract

We propose a way to realize a multiqubit controlled phase gate with one qubit simultaneously controlling $n$ target qubits using atoms in cavity QED. In this proposal, there is no need of using classical pulses during the entire gate operation. The gate operation time scales as $\sqrt{n}$ only and thus the gate can be performed faster when compared with sending atoms through the cavity one at a time. In addition, only three steps of operations are required for realizing this $n$-target-qubit controlled phase gate. This proposal is quite general, which can be applied to other physical systems such as various superconducting qubits coupled to a resonator, NV centers coupled to a microsphere cavity or quantum dots in cavity QED.