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Efforts to build an operational quantum computer are steadily progressing, but the “going is tough”. And it is not just a matter of battling noise in qubits: it is about building a complete industry, including fabricating qubits, integration into computer systems, incorporation into HPC, and quantum computer programming. As well as efforts in plain physical systems to get quantum computers up and running.

Qubits and pieces: Developments and Perspectives in Quantum Computing

by Artur Garcia-Saez, Christian Gamrat, Harm Munk and Paul Carpenter

Quantum technologies are becoming a revolution due to recent technological advances that have attracted a lot of industrial attention. Among these technologies, Quantum computation plays a central role due to its potential to provide a novel source of computational power to solve very hard problems. These results will be transformed into a novel set of devices of high precision, with the promise of novel applications and capabilities. Their development requires an environment not only of scientific research centers, but also auxiliary industrial partners with a high level of specialization.

Due to the strategic potential of this novel technology, many countries have already invested vast resources to develop their industrial capabilities, and to attract scientific talent. Europe has already started an initial set of projects defining its strategy for the upcoming years, but a careful analysis of the requirements to develop a global industry among different countries is required. The result of this analysis identifies the key components to create a powerful ecosystem for the upcoming years.

Key insights

  • The life cycle of some of the pioneering companies in QC is already showing stress symptoms, as the market conditions have evolved since the initial appearance of private actors. These changes may condition the future of the field, as companies have played an important role in recent developments.

  • Europe has pioneered several qubit technological paths: superconducting qubits, trapped ion qubits and neutral atoms, and is very active in the development of those technologies.

  • The race for making systems out of qubits is currently being led by players in the United States but Europe is narrowing the gap thanks to a number of innovative solutions developed by start-up companies. A successful European quantum computer industry also requires (re)building its industry providing the physical infrastructure required for quantum computing hardware.

  • Most available quantum programming frameworks originate from major US companies. European players are entering the discipline and are already proposing approaches for experimenting with quantum programming. Europe as a whole (European Commission and member states) is a strong competitor.

  • Europe is competing to train, attract and retain quantum talent. Education and training are critical for the European quantum computing ecosystem to be able to get up to speed. Access to quantum hardware and top researchers are essential to attract and retain talent.

  • The quantum computer will be part of a hybrid quantum/classical computer. A good synergy between quantum and computer science communities is required at both the hardware and software levels. The Quantum and HPC communities need to strengthen their cooperation and learn from each other.

Key recommendations

  • Support and advance research in the system architecture and software stack for quantum computing. With European assets in system, software and HPC technologies, this is a significant opportunity for Europe.

  • Invest in the development of design tools and libraries for quantum chip design and in their integration with classical technologies so as to provide an easier path towards prototyping and fabrication for both research and industry.

  • The chip technologies and industries will play a key role in developing and maturing new design methods, fabrication techniques and novel packaging for quantum computers. Recognize that they need to be supported and, in this context, the role of quantum pilot-lines will be key to provide access to prototype systems to the whole community including SMEs.

  • Design support and investment programmes to stimulate and promote the introduction of quantum technology in industry and society. Supporting technologies at large, e.g. infrastructures, should also be reinforced in order to build on the core quantum technologies (e.g. qubits) to make the advances in quantum technology real.

  • Since a quantum computer will be a hybrid classical/quantum system, high-performance computing (HPC) infrastructures will play a key role in integrating the required hybrid quantum system stack. Develop the integration of quantum accelerators into future exascale infrastructures. Promote the emergence of a European quantum cloud connected to quantum-hybrid HPC platforms. Develop software aspect, quantum stack. Hybrid computing: the marriage between HPC and Quantum.

  • Position Europe as a key player in the global race: Europe is the leader in the foundations of quantum physics: it should keep promoting basic research and novel ideas.

  • Europe needs to increase its support for new and small enterprises in the field, as well as promoting funding for scaling up, rather than being acquired by a non-European company. Developing and sustaining an ecosystem for these startups is also of paramount importance to prevent fragmentation.

  • Europe should promote academic and industrial research centers independent of U.S. and Chinese companies. Larger companies should be encouraged to take risks on quantum research.

  • Europe should also move to practical quantum computation, including the consolidation of a small number of easily accessible, highly usable quantum computing sandboxes in the cloud, with a strong eye towards ease of use.

  • Promote an attractive European quantum computing ecosystem with a balanced salary/benefits structure that will encourage talented people to stay in or relocate to Europe.

  • Many aspects of quantum computing and its applications are under development and require strong cooperation between the classical and the quantum computing communities: the communities are in a perfect position to learn from each other and thus strengthen their position in the world without reinventing the wheel.

  • In a competitive and cutting edge technological industry which quantum computing is, efficient and effective coordination among and across nations is very important.

  • Europe as a whole (European Commission and member states) is a strong competitor when levels of public funding are taken into account, but probably needs improved coordination to more effectively leverage available funding.

Quantum computing primer

Any computation makes use of some physical process that will transform data according to some rules. If we can manage to control these rules and make them equivalent to some logical operations, then we can make a computing device. Up to now, the rules used to build computers have been based on classical phenomena: the set of physical theories developed until the early 20th century.

Quantum theory was born to explain a number of experiments related to matter and light at the small scale that could not be explained by classical physics. As a side product, the formulation of this new physical theory provided a new set of rules that generalize those of classical logics. Using these rules, we can build a novel type of computing device based on the interactions described by quantum theory.

Figure 1 Illustration of two qubits in blue light with red light vertically (source:

Developing algorithms for this new type of computer has provided a novel perspective on the theory of computation and provided a very powerful result: by using quantum operations, one can design algorithms that solve problems (exponentially) faster than conventional computers. This is a major result, as advances in speed were based on improvements of the algorithms or improvements of the hardware, such as increasing the speed of a processor. However, the dramatic speedup for some problems using quantum computers are a result of the combination of a new formulation and a new set of operations, not available in classical logic. Quantum computation, a general case of the computers we use daily, provides more powerful computing devices. Shor’s algorithm to factor a number in its prime factors is often quoted as an example of this speedup, because it opens the road to find cryptographic keys. Once quantum computers become practical, this may well pose a threat to secure, encrypted communication. The key point here is that this requires a significantly larger quantum computer than is available now: for factoring a key of several thousand bits a logical qubit register of several thousand qubits is required. With the current state-of-the-art, this requires millions of physical (noisy) qubits. Such a large quantum computer is at least 10 to 15 years away, if not more (Preskill, 2018).

Nevertheless, quantum computing is casting its shadow ahead. And governments and organisations are already taking countermeasures. The government of the USA, e.g., now requires all its services to prepare for the security threat quantum computing will pose. It means that current encryption technologies are to be upgraded to a degree that even challenges quantum computing.

The European Union is preparing for this post-quantum era as well, mostly in the form of recommendations. Several national initiatives have evolved in the recent past. (See (NUKIB - Tsjech National Cyber and Information Security Agency, sd), and Attema, et al., 2023)”(PQC=Post-Quantum Cryptography).

In recent years, the connection between HPC and quantum computing started taking shape. Quantum computers with their complicated support electronics are, from a computer systems architectural point of view, accelerators, or coprocessors, not stand alone systems. In 2021, work has begun on the EuroHPC JU “Pilot on quantum simulator” project <HPC|QS>. The aim of <HPC|QS> is to prepare European research, industry and society for the use and federal operation of QCS. <HPC|QS> is developing the programming platform for the QS, which is based on an emulating platform provided by a European company, and the deep, low-latency integration into modular HPC systems based on ParTec’s European modular supercomputing concept. A twin pilot system of QSs, developed as a prototype by a European company, will be implemented and integrated at CEA/TGCC (France) and Forschungzentrum Jülich/Jülich Supercomputing Centre (Germany), both hosts to/of European Tier-0 HPC systems. The pre-exascale sites BSC (Spain) and CINECA (Italy) as well as the national Quantum Learning Platform at ICHEC (Ireland) will be connected to the TGCC and Jülich Supercomputing Centre via the European data infrastructure FENIX (Ref QFLAG SRIA 2030, to be published). The <HPC|QS> serves as a seed project for the upcoming EuroHPC QS program, after the selection of 6 European centers as hosting entities for a new generation of Quantum computers that will operate the systems on behalf of the EuroHPC JU. This quantum computer infrastructure will support the development of a wide range of applications with industrial, scientific and societal relevance for Europe, adding new capabilities to the European supercomputer infrastructure.

It is often asked what the “killer application” of quantum computing will be. Without available practical quantum hardware allowing for large scale experimentation, that question is difficult to answer. For the near future, whatever that means for quantum computation, it seems to be the simulation of physical quantum systems, such as the structure of complex molecules. A slightly different quantum computational type of device, based on Rydberg atoms, is a likely candidate to provide the computational power for such simulations.

Figure 2 A pentagon of super atoms: The illustration depicts the densest possible ordering of five Rydberg excitations in an ensemble of rubidium atoms that are pinned in an optical lattice (source:

The global race for quantum computing

Quantum computing is built on the foundations of quantum mechanics laid out by European scientists at the dawn of the 20th century. Since then, Europe has continued to excel in fundamental quantum physics. However, now that the utilization of quantum computing and communication are emerging we are entering an era of global competition in several very concrete fields.

Figure 3: Solvay conference 1927

Europe pioneered several technological paths for qubit technology (first demonstration of superconducting quantum gates [11], trapped ion qubits [12]) and has a strong position in promising technologies such as neutral atoms (Pasqal: and semiconductors.

Europe must get up to speed in quantum computing systems hardware. Proofs of concept and innovative solutions are developed by pioneering European startup companies and research labs, but larger quantum chips so far have been made by US companies. Europe is now changing gears as suggested by the roadmaps from the "Quantum Flagship Initiative" ( and the association of European Industrial for Quantum technologies (

In software, most available quantum programming frameworks originate from major American companies. In Europe, some players (ATOS:, VeriQloud:, Quantum Inspire: are well in the race and already propose approaches to allow experimenting with quantum programming using quantum computer simulators and quantum computer hardware. Also important to mention are the efforts of hardware start-ups that experiment with their platforms by providing cloud access to their programming tools like Quandela cloud (

Europe is struggling with funding among nations. The overall public funding (EU as a whole plus individual member states) compares well by being head to head with the U.S. and China, but this hides the fact that each member state has its own agenda and funding strategies. Initiatives such as the already mentioned Quantum Flagship should bring more coordination. The situation is very different for private funding needed by the industry. Due to the lack of significant risk funding opportunities in Europe, companies might not find the resources to support their growth: some might find better opportunities elsewhere, some might simply die.

Figure 4 PhD student Alex Greene working on a superconducting quantum computing system at MIT (source:

Last but not least, Quantum Technology is also a race for talents. To achieve this goal, 20 Universities from ten European countries are setting up an education and training program for quantum technologies in Europe with 16 new specialized Master's degrees: DigiQ (Digitally Enhanced Quantum Technology Master), the primary workforce development project of the Quantum Flagship ( But beyond training future quantum experts, Europe also needs to attract and keep the best talents of the world by offering attractive opportunities in its research and industry sectors.

Further reading:

Quantum internet

A quantum internet is an application of quantum networks. Quantum networks enable the communication of qubits. Such networks can be used to connect quantum processors to form more powerful quantum computers. Quantum networks can also be used to create quantum internet applications. One such application is the secure distribution of cryptographic keys: in this setup, cryptographic keys are distributed over a quantum network using entangled qubits, enabling the detection of eavesdropping on the communication. But quantum internet, just like quantum computers, are under development and are still much in the research phase. Practical applications at this moment require complicated setups, often involving cryogenically-cooled devices, preventing wide-spread use today and in the next few years. (Singh, Dev, Siljak, Joshi, & Magarini, 2021)


Quantum computing will have an indirect impact in the next few years with respect to embedded software development and embedded software. It depends on the speed of evolution and innovation of quantum technology when quantum computing devices will leave the laboratory and make their introduction to the industry. For now, that appears to be at least a decade away, but vigilance on this subject is required. And Europe should strive for independence from other nations in this area to be able to develop this technology on its own, in the light of the recent developments in international relations.


Artur Garcia-Saez is a researcher at the Barcelona Supercomputing Center (Spain), and a co-founder of Qilimanjaro Quantum Tech.

Christian Gamrat is a researcher in the Research and Technology Department at CEA (Alternative energies and Atomic Energy Commission), France.

Harm Munk is project leader at TNO, The Netherlands.

Paul Carpenter is a researcher in the Computer Sciences Department at Barcelona Supercomputing Center, Spain.


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[12]: J. I. Cirac and P. Zoller, “Quantum Computations with Cold Trapped Ions,” Phys. Rev. Lett., vol. 74, no. 20, pp. 4091–4094, May 1995.

The HiPEAC project has received funding from the European Union's Horizon Europe research and innovation funding programme under grant agreement number 101069836. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union. Neither the European Union nor the granting authority can be held responsible for them.