Quantum computing is attracting increasing interest from companies worldwide and the international scientific community. Its main promise is to significantly reduce computation time through the physical phenomena of state superposition and quantum entanglement. This would enable faster resolution of problems whose complexity (number of operations) grows exponentially with their size. Indeed, a quantum computer with 𝑛 qubits (a qubit is a quantum bit, which is the elementary unit capable of carrying quantum information) would be 2𝑛 times faster than a conventional computer with 𝑛 bits. It would therefore be capable of processing a much larger number of cases.
For example, the best algorithm for finding the route that minimises the total distance travelled to visit the 319 UNESCO World Heritage sites in France requires approximately 66∗10661 operations on a conventional computer, making it impossible to obtain the optimal solution within a reasonable time. A quantum algorithm would require far fewer operations thanks to quantum parallelism (superpositions), where several calculations occur simultaneously, enabling reasonable computation time. However, this algorithm has not yet been discovered.
Another example illustrates a different challenge that quantum computing faces. An algorithm can easily solve a crucial problem in cryptography on a quantum computer. A 600-digit key used to secure Internet exchanges through RSA encryption could be “cracked” in a few hours by Shor’s quantum algorithm, if a quantum computer with several million qubits existed. Such a computer has not yet been built, but authorities responsible for information security are already concerned about this threat.
As we can see, quantum technology still faces many challenges, both mathematical and physical.
In France, major corporations (La Poste, Total, Thales, Airbus, and others) are developing quantum strategies, roadmaps, or innovation plans to gain a strategic advantage and protect themselves against future computing power that could be used maliciously.
EURODECISION is interested in this innovation axis as part of a project with a long-standing client, the Banque de France. We are helping them develop a settlement engine for cross-border transactions and innovate in how optimization problems in this financial application are solved. As a result, we are evaluating the potential benefits of quantum computing for solving the transaction settlement problem compared with classical algorithms.
The conference “21st EU/ME meeting x Quantum School Emerging optimization methods: from metaheuristics to quantum approaches“, which took place in Troyes from 17 to 21 April 2023, enabled us to keep informed of the state of the art in quantum physics and computing thanks to stakeholders from the various fields related to this innovative technology. It was an opportunity to test quantum approaches to solving optimisation problems on various platforms from IBM, PASQAL, D-Wave, and Atos/Eviden, as well as to take a guided tour led by its director, Christophe Couteau, of the L2N research laboratory in Troyes, which works notably on the nanotechnologies essential for manufacturing quantum computers.
To find out more, discover our overview of quantum computing technologies for optimisation problems