Benefits and Challenges of Designing Cryogenic CMOS RF Circuits for Quantum Computers

Accurate and low-noise generation and amplification of microwave signals are required for the manipulation and readout of quantum bits (qubits). A fault-tolerant quantum computer operates at deep cryogenic temperatures (i.e., <; 100mK) and requires thousands of qubits for running practical quantum algorithms. Consequently, CMOS radio-frequency (RF) integrated circuits operating at cryogenic temperatures down to 4 K (Cryo-CMOS) offer a higher level of system integration and scalability for future quantum computers. In this paper, we extensively discuss the role, benefits, and constraints of Cryo-CMOS for qubits control and readout. The main characteristics of the CMOS transistors and their impacts on RF circuit designs are described. Furthermore, opportunities and challenges of low noise RF signal generation and amplification are investigated.

I. Introduction

Quantum computing promises to solve specific computational problems exponentially faster than any imaginable digital computer. These problems include DNA analysis, effi-cient search in gigantic data sets concerning medical research, consumer behavior and financial markets [1], and optimization of materials and industrial chemical processes [2]. Quantum mechanics permits a particle to exist in a superposition state and be entangled to physically separated systems. These phenomena are exploited by quantum machines to simultaneously produce rich configuration states and highly correlated behav-ior to tackle classically intractable computational problems.