SuPErConducTing Radio-frequency switch for qUantuM technologies

Introduction

Despite the high expectations and numerous announcements that have been made over the past ten years, the spread of Quantum Computers (QCs) is still in its infancy. The major factors limiting the diffusion and market penetration of QCs are their low scalability and high cost.

Challenges

Both issues are connected to the bulkiness and complexity of the signal lines that operate the QC. The required large amount of cables undermines the scalability and decreases the thermal stability of the Quantum Processing Units (QPUs).

Project Goals

With this project, we aim to increase the scalability and reduce the thermal issues of QPU by developing a radiofrequency (RF) switch, QueSt, that allows simultaneous control of the state of multiple qubits through the same cable.

Innovation

QueSt goes well beyond what is achieved with state-of-the-art electronics that typically provide bulky, slow, and energy inefficient solutions. The core component of QueSt is an all-metallic superconducting transistor controlled via gate voltages. This transistor exploits the peculiar characteristics of a superconducting material to work at frequencies (~1 THz) unachievable with classical semiconductor electronic components and with nearly zero power dissipation.

Implementation

During SPECTRUM, we are going to build a complete test platform for QueSt devices. The state-of-the-art nanofabricated prototype of QueSt will be tested in a custom-made cryostat able to unleash the true potential of this technology.

Control Mechanism

Furthermore, ultra-fast FPGA-based electronics will take care of the control of multiple switches, providing an affordable and performant control over the prototype.

Research Environment

This platform will be the environment in which QueSt will be studied in strict contact with the state-of-the-art Quantum Processing Units. The experiments performed in real Quantum Computers under the EU-funded Spectrum project will be the first step towards the true Quantum Revolution.