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Quantum computing promises to dramatically impact numerous fields, from cybersecurity to finance, from supply chain to pharmaceuticals, and from defense to weather forecasting.

The challenge for quantum bits (qubits) is to make them increasingly stable in order to optimize performance. Platforms with more than 1,000 qubits will appear in the coming years, with several companies like IBM, Amazon, and Microsoft investing more and more. Companies are competing on several aspects: the number of qubits, the types of ports available, connectivity between qubits, error rates, and operating temperature.

“Nature is made of tiny particles — atoms, electrons, and even smaller subatomic ones,” said Nir Minerbi, CEO and co-founder of Classiq. “The interaction between these particles is different than objects that we see in our day-to-day lives. Quantum technology relies on the unique, and sometimes strange, physical properties of these tiny particles.”

According to Minerbi, the key principles of quantum theory that have direct implications for quantum computing are superposition (the ability of a particle to be in multiple states at the same time), entanglement (the ability of particles to be correlated even if they are very far apart), and interference (the ability of particles to amplify or cancel each other out).

Eric Mounier, director of market research at Yole Intelligence, part of Yole Group, said that R&D is still very active and will continue to be as quantum technologies are definitively strategic for the future.

“For example, Xanadu [Canada] reported quantum advantage in June and showed 216 squeezed-state qubits; it made its capabilities available to the public through the Xanadu cloud and Amazon Braket,” said Mounier. “In 2020, China demonstrated quantum advantage by also using a photonic computer, while in 2019, Google announced it was the first to achieve quantum advantage. Besides the U.S., India [$1B planned], Japan, and China are also very active in quantum development. Europe is strong in R&D, with Delft University and CEA-Leti developing CMOS-compatible quantum technologies.”

“Commercial quantum computers are already available,” said Minerbi. “These computers are made of qubits and quantum gates. There are various technologies used to create qubits and thus various kinds of qubits: superconducting qubits, trapped ion qubits, photonic qubits, and several others. There is a lot of research into improving the quality of qubits and gates, the software algorithms that take advantage of unique quantum properties, and methods to create larger-scale quantum computers.”

According to Mounier, quantum’s greatest challenges are reducing errors due to the decoherence phenomenon: Decoherence is the error caused by the coupling of quantum systems in the external world.

“As the number of qubits increases, so does the decoherence — it is the primary source of error in quantum computers,” said Mounier. “Having sufficient physical qubits: 50 is the minimum number of logical qubits to enable quantum computing that begins to exceed the practical limits of modern classical computers. But many experts believe quantum computers will need at least 1 million qubits to become useful from a commercial standpoint.”

“Quantum computers are susceptible to the outside environment and to imperfections in the manufacturing process,” said Minerbi. “As a result, they are limited in how long they can hold values before these are corrupted. Companies are working on both improving this characteristic as well as developing error-correction mechanisms so that when errors occur, they can be detected and corrected.”

Mounier highlights that the three other challenges for a commercial Q computer are:

- Implementing surface code error correction to detect and correct the fragile quantum states of individual qubits
- Developing “agnostic” software
- Developing new electronic hardware to control individual qubits and read out results (also the cryogenic hardware)

In terms of software/hardware system stacks, Mounier said that quantum computers require totally different software than classical computers, and two distinct approaches are seen:

- Some large companies are developing quantum computers and are also developing their own languages.
- Some new companies are proposing quantum technology-agnostic software that could be used by different quantum platforms/players, such as Google or IBM.

“In any case, the lack of standardized quantum software could delay the adoption of quantum computing, as was the case for FPGAs in the past,” Mounier added.

**Exciting quantum development**

According to Mounier, using photonic technology is exciting and is an active R&D field today. In fact, scaling down optical circuits is possible with silicon photonics employing CMOS technologies. Additionally, because photons function at room temperature, they offer a benefit in terms of handling. They can use silicon technology in the design and production of their chips.

“Photonics and silicon photonics can be used to manipulate ions for quantum computing,” said Mounier. “Several research projects are ongoing to realize quantum computing using ion qubits, which are manipulated by lasers. For example, IonQ and the Duke Quantum Center have already achieved quantum computing using 32 ions. To reduce the size of the quantum computer, it is possible to use laser and photonic components integrated onto a chip. Such research is performed by the MIT Lincoln Laboratory, which has demonstrated the use of silicon photonics for individual ion manipulation. IonQ plans to use silicon photonics for ion qubit quantum computing by 2023. So there are many companies using photon qubits: QuiX [The Netherlands], Xanadu, and PsiQuantum [U.S.]. PsiQuantum and GlobalFoundries have announced a partnership to build the world’s first full-scale commercial quantum computer. The two companies are now manufacturing the silicon photonic and electronic chips that form the foundation of the Q1 system, the first system milestone in PsiQuantum’s roadmap to deliver a commercially viable quantum computer with 1 million qubits.”

**E-mobility and energy sectors**

In e-mobility and energy, there are many applications for quantum computing.

“One interesting application is the development of solid-state batteries,” said Mounier. “The developmental effort of a solid-state battery is still diluted by the multitude of different approaches.”

“There are two main directions: optimization and material science,” said Minerbi. “Quantum-powered optimization will help design better energy distribution grids, optimize transportation — and thus save energy — and optimize the supply chain. Quantum-powered material science will generate better EV batteries — lighter yet with greater capacity — and help reduce energy consumption in chemical processes such as Haber-Bosch and more.”

Meanwhile, BMW Group and Pasqal expanded their collaboration to apply quantum computing to improve car design and manufacturing. The next phase of collaboration aims to make BMW Group’s cars safer, lighter, and more fuel-efficient through accelerated simulations.

Highly accurate computational simulation would allow BMW Group to replace costly physical build-test-improve cycles, as current classical computational methods are incapable of dealing with the complexity of simulating a full vehicle at the desired accuracy. Such simulations will ultimately help BMW Group create lighter parts, making cars more fuel-efficient.

**Future vision for quantum computing**

Simulation on quantum computers will come first, then applications for scenario optimization and machine learning. Scenario forecasting, however, is more difficult and is not expected to be employed before 20 to 30 years from now.

“Regarding specific applications, pharmaceutical is today attracting most of the attention for quantum computing,” said Mounier. “However, it will take many years, maybe 20 to 30, before quantum is widely used in medical and pharma applications. Quantum computing will be ready to be used for drug development in five to 10 years, when there is already an identified drug candidate. For drug discovery, it will be ready in 10 to 20-plus years. Following the adoption of quantum in pharmaceuticals, other applications could follow: energy, chemistry, transportation, banks, and finance could adopt quantum computing in 10-plus years.”

“Quantum computing will become a central pillar of any serious computing architecture,” said Minerbi. “Just like the CPU and GPU, the quantum processor unit [QPU] will be a critical component of any data center. These QPUs, alongside CPUs and GPUs, will solve problems that can never be solved by classical computers and deliver huge societal benefits,” said Minerbi.

**Relationship between cyber and quantum computing**

The advent of quantum processors capable of performing the Shor’s algorithm would make asymmetric algorithms such as RSA, ECC, or all cryptographic algorithms based on integer-factoring mathematical problems, discrete logarithms, and discrete logarithms on elliptical curves completely insecure.

“Post-quantum cryptography — sometimes referred to as quantum-proof, quantum-safe, or quantum-resistant — refers to cryptographic algorithms, usually public-key algorithms, that are thought to be secure against an attack by a quantum computer,” said Mounier. “This can be considered as cybersecurity. The post-quantum–cryptography market will grow. We estimate the inflection point will be after 2028–2030, as it will be determined by future announcements of available quantum computers.”

“Quantum technologies have many points of intersection with cybersecurity,” said Minerbi. “Quantum phenomena can be used to securely distribute encryption keys or to provide unhackable communications links. Strong quantum computers will be able to crack the RSA encryption and other classical encryption methods. Quantum computing can also help secure existing networks and software by detecting new vulnerabilities.”

Almost all the algorithms in use with public-private key and used daily for web browsing are subject to Shor’s algorithm, which makes them insecure. There is, therefore, the need to develop new algorithms in a so-called post-quantum phase, i.e., identify and create cryptographic algorithms that will remain secure after the advent of quantum processors. The researchers are proposing several post-quantum–cryptographic algorithms with different approaches and based on different mathematical problems that would imply a high consumption of network resources.

**Conclusion**

A unique property of quantum computers is that their power scales exponentially with the addition of every qubit, whereas classical computers scale linearly with the addition of every bit. According to Minerbi, as a result, quantum computers can solve problems that classical computers can’t and never will. So it’s not just about speed, it’s about the ability versus inability to solve certain types of problems.

“Many large and well-funded organizations are working to build quantum computers with tens of thousands or even millions of qubits, whereas today, the largest computers have about 100 qubits,” Minerbi added. “These larger computers will be able to solve a new class of problems as well as implement error correction to help them overcome some of the problems of today’s computers.”

*This article was originally published on **EE Times Europe**.*

*Maurizio Di Paolo Emilio** holds a Ph.D. in Physics and is a telecommunication engineer and journalist. He has worked on various international projects in the field of gravitational wave research. He collaborates with research institutions to design data acquisition and control systems for space applications. He is the author of several books published by Springer, as well as numerous scientific and technical publications on electronics design.*