A proposal for realizing a 3-qubit controlled-phase gate with superconducting qubit systems coupled to a cavity

TL;DR

This paper proposes a fast, adjustable 3-qubit controlled-phase gate for superconducting qubits coupled to a cavity, avoiding the need for level adjustment or identical couplings, applicable to various quantum systems.

Contribution

It introduces a general, fast method for implementing a 3-qubit controlled-phase gate without requiring identical qubit-cavity couplings or level adjustments.

Findings

Gate can be performed within ~10 nanoseconds

No need for adjusting qubit level spacings

Applicable to various quantum systems

Abstract

We present a way to realize a 3-qubit quantum controlled-phase gate with superconducting qubit systems coupled to a cavity. This proposal does not require adjustment of the qubit level spacings or identical qubit-cavity coupling constants. Moreover, since only a resonant interaction is applied, the gate can be performed fast, within $\sim $ 10 nanosecond. This proposal is quite general, which can be applied to various types of superconducting qubits, atoms trapped in a cavity, or quantum dots coupled to a resonator.