Summary
Quantum computers are a type of computer harnessing the properties of quantum states, e.g., superposition, interference, and entanglement, for computation. Its basic unit is a quantum bit, also called a qubit, that can assume any superposition between the two states “0” and “1”. By using these superposition states rather than just single binary states, quantum computers will implement specific algorithms, e.g., Shor’s algorithm for prime number factorization, exponentially faster and thereby allowing computations that wouldn’t be practically feasible on a classical computer. Hardware platforms for implementing qubits are superconducting, trapped ion or neutral atom systems, nitrogen-vacancy centers, photons, or topological quantum computers. Leading companies include IBM, Rigetti, IonQ, and many more.
Viability (2)
Fundamental operations of a quantum computer have been demonstrated experimentally with high accuracy; it remains hard to deal with many qubits and implement entire quantum algorithms due to decoherence and the lack of error correction. While it’s not clear whether error correction will be possible, NISQ computers like superconducting and ion trap systems are promising for HPC; diamond quantum computers involving NV-centers are promising for room-temperature and edge applications. High degree of uncertainty that general-purpose fault-tolerant quantum computers are viable at all. It’s therefore close to a guess because we need a scientific breakthrough and we can’t forecast those. Google still claims a “useful, error-corrected quantum computer” by 2029. With all the major technology companies and Governments investing billions in quantum, we can have greater certainty that NISQ computers targeting specific applications, in particular HPC, will demonstrate value in 3-5 years.
Drivers (5)
Quantum computers can solve certain problems efficiently (polynomial in time) that a classical computer cannot solve within a reasonable time. This quantum supremacy is the main driver for the development of quantum computers, with high value applications in pharma and manufacturing with quantum chemistry and fluid dynamics for drug development as well as finance (portfolio optimization), logistics (route & supply chain planning). Quantum processing units (QPUs) may also be more widely adopted if they just outperform GPUs and CPUs in weight, size, or cost.
Novelty (5)
QPUs (quantum processing units) will complement, not replace, traditional CPUs/GPUs in high-performance computing centers. They will be primarily used for special use cases where quantum supremacy/utility is evident. Competition arises from optimized algorithms on classical supercomputers – a moving frontier – and other innovative computing architectures such as analog computers.
Diffusion (3)
HPC facilities will be the first to adopt QPUs: Either because they outperform CPUs/GPUS for particular operations (quantum utility) or because they allow for specific computations exponentially faster (quantum supremacy). The main barriers are the extremely high construction, maintenance, and operation costs. Additionally, the expertise needed to develop quantum algorithms and potentially regulation and antitrust investigations in corporations developing quantum computers may slow development and adoption.
Impact (5)
The low certainty high-impact scenario sees a general-purpose error-correcting quantum computer with quantum supremacy replacing almost all of our computing tasks both server-side and client-side. Still a high impact, but less so, would be just replacing server-side computing for particular tasks. Somewhere on the medium impact scale are NISQ computers for HPC which would still be highly impactful for material science, computational biology, and large-scale simulation workloads. A scalable general-purpose error-correcting quantum computer would open up a range of applications that is is hard to envisage today including new materials, molecules and simulations that will likely lead to a leap forward in science, innovation and therefore economic growth and human flourishing.
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