Practical Applications with Quantum Computers

Kevin J. Sung

Noisy intermediate-scale quantum (NISQ) computers are coming online. The lack of error-correction in these devices prevents them from realizing the full potential of fault-tolerant quantum computation, a technology that is known to have significant practical applications, but which is years, if not decades, away. A major open question is whether NISQ devices will have practical applications. In this thesis, we explore and implement proposals for using NISQ devices to achieve practical applications. In particular, we develop and execute variational quantum algorithms for solving problems in combinatorial optimization and quantum chemistry. We also execute a prototype of a protocol for generating certified random numbers. We perform our experiments on a superconducting qubit processor developed at Google. While we do not perform any quantum computations that are beyond the capabilities of classical computers, we address many implementation challenges that must be overcome to succeed in such an endeavor, including optimization, efficient compilation, and error mitigation. In addressing these challenges, we push the limits of what can currently be done with NISQ technology, going beyond previous quantum computing demonstrations in terms of the scale of our experiments and the types of problems we tackle. While our experiments demonstrate progress in the utilization of quantum computers, the limits that we reached underscore the fundamental challenges in scaling up towards the classically intractable regime. Nevertheless, our results are a promising indication that NISQ devices may indeed deliver practical applications.

Dennis Willsch

Petri Liimatta, Pauli Taipale, Kimmo Halunen +3 more

The emergence of quantum computing proposes a revolutionary paradigm that can radically transform numerous scientific and industrial application domains. However, realizing this promise in industrial applications is far from being practical today. In this paper, we discuss industry experiences with respect to quantum computing, and the gap between quantum software engineering research and state-of-the-practice in industry-scale quantum computing.

Seiki Akama

Esam El‐Araby, Manu Chaudhary, Ishraq Islam +5 more

With the rapid advancement of quantum computing technology, there is a strong motivation to explore suitable practical applications for quantum algorithms and quantum computers. This chapter focuses on reviewing recent research on practical applications of quantum computing, specifically dimension reduction, pattern recognition, quantum sorting, and quantum communications for which optimized/modified versions of the quantum wavelet transform (QWT) and Grover’s algorithm are presented. For practical implementations of the presented algorithms, this chapter also includes methodologies for classical-to-quantum (C2Q) data encoding and quantum-to-classical (Q2C) data decoding. Additionally, the chapter presents an efficient quantum sorting technique by combining perfect-shuffle and bitonic networks. In the domain of quantum communications, the chapter reviews a technique that combines chaotic communications with quantum key distribution (QKD) to enhance both security and communication range. The effectiveness of these techniques is validated through practical results obtained from experiments conducted on IBM-Q simulators and hardware, as well as on high-performance-reconfigurable-computers (HPRCs). This chapter aims to provide readers with a comprehensive understanding of these applications, covering the necessary prerequisites by showcasing the potential of quantum computing in various domains for innovative problem-solving.

Patrick M. Lenahan