Digital-Analog Quantum Simulation and Computing: A Perspective on Past and Future Developments

TL;DR

This paper reviews the evolution and future prospects of digital-analog quantum technologies, which combine digital and analog paradigms to enhance scalability and versatility in quantum simulation and computing.

Contribution

It provides an overview of the past decade's developments and discusses future directions for digital-analog quantum simulation and computing.

Findings

Digital-analog approaches enable scalable quantum simulations.

Combining analog blocks with digital gates offers versatility and potential universality.

The field has evolved significantly over the past decade with promising future prospects.

Abstract

Quantum simulation and computing traditionally has been based on two main paradigms, namely, digital and analog. In the digital paradigm, usually single and two-qubit gates (where qubit is an acronym for quantum bit) are employed as building blocks for scalable, universal quantum computing, although errors add up fast and error correction will be ultimately needed for scaling up. In the analog paradigm, large analog blocks are normally employed for a unitary dynamics that carries out the computation, enabling quantum operations on many qubits with reduced errors, but with the drawback of a limited choice of evolutions and lack of universality. In the past decade, a new paradigm has emerged, showing interesting possibilities for quantum simulation and computing in the near and mid term. This is the paradigm of digital-analog quantum technologies, which proposes to combine the best of both paradigms: large analog blocks, provided by native interactions of the employed quantum platform, enabling scalability, combined with digital gates, allowing for more versatility and, ultimately, universality. In this Perspective, I give an overview of the evolution of the field along the past decade, and an outlook for its future possibilities.