How silicon-chip technology is being re-engineered for quantum computing

Xiao, Yunfeng Yunfeng, Han +3 more

C. C. Lo, John J. L. Morton

Grand engineering challenges often require an epic level of patience. that's certainly true for quantum computing. For a good 20 years now, we've known that quantum computers could, in principle, be staggeringly powerful, taking just a few minutes to work out problems that would take an ordinary computer longer than the age of the universe to solve. But the effort to build such machines has barely crossed the starting line. In fact, we're still trying to identify the best materials for the job. Today, the leading contenders are all quite exotic: There are superconducting circuits printed from materials such as aluminum and cooled to one-hundredth of a degree above absolute zero, floating ions that are made to hover above chips and are interrogated with lasers, and atoms such as nitrogen trapped in diamond matrices.

L. Oberbeck, S. Prawer, Andrew S. Dzurak +28 more

Lawrence M. Rosenfeld, Dominic A. Sulway, Mark G. Thompson +2 more

Summary form only given. Quantum computing technology is at a crossroads. The technological route we choose must scale without limit. For quantum optics to play a part, optical loss, miniaturisation, and manufacturability must be simultaneously addressed. In quantum optics, a loss of a single photon is a loss of irreplaceable quantum information. Macroscale optics offers exceptionally low loss, and high performance, but has no hope to scale to thousands or millions of modes. Microscale optics, and silicon photonics in particular, offer exceptional miniaturisation and large-scale manufacturability, but pay a high price in loss [1]. We propose -and realise -a new platform for quantum optics: we retain the scale and manufacturability of silicon photonics, but extirpate its loss, both linear and nonlinear. We shift silicon quantum photonics to the short-wave infrared (SWYR), centred on 2.1 microns wavelength, on the optical end of the mid-infrared spectrum [2]. The minimum requirements for any quantum optical platform are: to source quantum-correlated light, and to demonstrate high-quality quantum interference. Here, we do both: we engineer an on-chip photon-pair source, and interfere the light from two such sources in a time-reversed Hong-Ou-Mandel (HOM) measurement [3]. In so doing, we show the first photon-pair source with all fields in the mid-infrared, and the first quantum interference between mid-infrared photons. We coherently pump both on-chip sources and thermally vary the on-chip phase, (j) to perform a time-reversed HOM interference measurement [3] with an accidental-subtracted visibility of V = 99.1 ± 0.9%.

Samuel Sepúlveda, Ania Cravero

Context: Quantum computing (QC) represents a paradigm shift in computational capabilities, presenting unique challenges in requirements engineering (RE). The complexity of quantum systems and rapid technological advancements necessitate a comprehensive understanding of the current state and future trajectories in RE for QC. Objective: A protocol for carrying out a systematic literature review about the evidence for identifying and analyzing the challenges in RE for QC software. It seeks to evaluate the current methodologies employed in this domain and propose a forward-looking perspective on the evolution of these methodologies to meet future industry and academic needs. Method: This protocol employs a structured approach to search and analyze relevant literature systematically, according to Barbara Kitchenham's guidelines. Results: A validated protocol to conduct a systematic review. The protocol is expected to yield diverse literature spanning theoretical frameworks, empirical studies, and methodological advancements in RE for QC. It will highlight the current challenges, opportunities, and future directions, offering insights into the field's academic and practical aspects. Conclusions: The systematic review aims to provide a nuanced understanding of the RE landscape in QC. It will offer valuable insights for academic researchers, industry professionals, software engineers, industry analysts, and educators, shaping the future discourse in QC development.

Laurie Donaldson