Quantum logical gates with four-level SQUIDs coupled to a superconducting resonator

TL;DR

This paper presents a fast, efficient method for implementing a two-qubit controlled phase gate using four-level SQUIDs coupled to a superconducting resonator, avoiding complex adjustments and adiabatic processes.

Contribution

It introduces a novel scheme for quantum gates with four-level SQUIDs that is faster and simpler than previous methods, not requiring level adjustment or adiabatic passage.

Findings

The proposed method enables faster two-qubit gates.

No need for SQUID parameter uniformity or level adjustment during operation.

The scheme avoids adiabatic processes, increasing speed.

Abstract

We propose a way for realizing a two-qubit controlled phase gate with superconducting quantum interference devices (SQUIDs) coupled to a superconducting resonator. In this proposal, the two lowest levels of each SQUID serve as the logical states and two intermediate levels of each SQUID are used for the gate realization. We show that neither adjustment of SQUID level spacings during the gate operation nor uniformity in SQUID parameters is required by this proposal. In addition, this proposal does not require the adiabatic passage or a second-order detuning and thus the gate is much faster.