Quriosity: quantum-enhanced information processing

Dialogue between research and industry

Keeping an open mind when it comes to any possibilities for innovation is very much the guiding principle for the Inria project team Quriosity, a joint undertaking with Télécom Paris and the Institut Polytechnique de Paris. “Our aim is not to plan for some hypothetical reality where we would have unlimited resources”, explains Romain Alléaume, Professor at Télécom Paris and head of Quriosity, a team that was set up in January 2023 and which is based at the Inria Saclay centre. “Rather, our aim is to establish a dialogue between research and industry aimed at producing applications capable of being deployed right away using existing quantum technology.”

One area the team will be placing a particular emphasis on is cryptography. On one hand are traditional cryptography tools, such as those used to secure data exchange online. These rely on the difficulty of solving certain mathematical problems - or computational hardness assumptions - and are vulnerable to ever-expanding processing capacities and future breakthroughs in algorithmics. On the other there is quantum cryptography, which involves the transmission of randomly generated qubits and can guarantee high levels of security. This method has its roots in quantum and does not involve computational hardness assumptions, although its application scope is more limited.  

Creating a hybrid of standard and quantum cryptography

The solution lies in devising hybrid solutions, which is precisely one of the areas of research that Quriosity will be focusing on. “When it comes to cryptography, the main advantage of quantum is that quantum information cannot be cloned:  if someone wants to extract information, then errors will automatically appear, and  access to the information can be blocked”, adds Romain.

Quriosity is also seeking to boost the security of cryptographic hardware by developing digital systems with a quantum layer as part of their physical layer.

Another aspect the team is looking to explore is the development of cryptographic protocols for which security can be ensured, even when using untrusted devices. “By using what is known as quantum entanglement, we can ensure that our tools produce a secret key, even in the worst case scenario where a device has ended up in the hands of an attacker”, explains Peter Brown, lecturer at Télécom Paris and a member of Quriosity. “These cryptography protocols are device-independent, meaning they can be applied to device that are not controlled by the legitimate players and yet can  deliver very high levels of security, including for the cryptographic generation of random numbers, for example. Device-independent quantum cryptographic protocols are however currently difficult to implement.” This is one obstacle which Quriosity is hoping to overcome.

Large-scale photonic systems

Another area of focus involves harnessing high-dimensional degree of freedom of photons - such as their arrival rate or their frequency - for the processing of quantum information. “We know how to produce quantum states for light that are in coherent superposition over thousands or even millions of modes. The major challenge will be how to control the ‘noise’”, explains Romain Alléaume. In other words, to keep unwanted interactions with the external environment - which affect qubits during execution of an algorithm, caused by factors such as thermal agitation - to a minimum. “We hope to achieve this by combining these systems with digital methods that have the capacity to estimate and reduce errors, such as signal processing or machine learning “. Large-scale photonic systems could prove really effective when it comes to developing error-tolerant quantum processing architecture.

Finally, the team is also seeking to actively contribute to the theoretical research on the mathematical foundations of quantum computing and information. The long-term objective is to develop a deeper understanding of large entangled quantum systems - systems comprising hundreds of particles - in order to identify the best algorithmic properties and tolerance to errors when it comes to executing calculations. Such problems will be central to the quantum technology of the future. Cambyse Rouzé, who joined Quriosity in a permanent “Starting faculty position” role with Inria, is focusing his research in this field “on the characterization of noise in hybrid quantum computing models”. As he explains, “One particularly difficult problem, at the point where theoretical computer science meets physics, involves predicting the properties of molecules and complex solids at low temperatures. The team is developing new algorithms inspired by statistical physics in order to be able to approximate these properties. To give you an example, we are hoping to find new memories capable of storing  quantum information for longer periods of time.”

A national quantum ambition

The creation of Quriosity is also part of a wider effort aimed at accelerating research and industrial development in the field of quantum technology, guided by France’s National Quantum Plan, which was launched in 2021. Three main hubs have been identified for this in France: Paris-Centre, Grenoble and Paris-Saclay.

For Saclay, one of the key strategic challenges will be to consolidate its expertise in quantum computing through the development of specialist teams. Quriosity is the second team based at the Inria Saclay centre to focus on quantum, the first, QuaCS, having been created in 2021 with Paris-Saclay University. A third is expected to be launched soon with the Institut Polytechnique de Paris. This dynamic has been boosted by the recent launch of the Quantum-Saclay centre, which the Institut Polytechnique de Paris and Paris-Saclay University joined forces to create. As Romain Alléaume explains, this process is the evidence of “the motivation and strong drive of the Saclay ecosystem where leading quantum spin-offs such as Quandela and Pasqal are already  hosted, to move to another level within the quantum landscape”.

To know more

• [DECODE Quantum] Meet Romain Alleaume, researcher in quantum communications (podcast), FrenchWeb.fr, 16/3/2022.
• Seminar@SystemX with Romain Alléaume (video), “Quantum technology, a new frontier for information processing”, IRT SystemX, 25/1/2022.
• The creation of QUANTUM, Paris-Saclay University’s centre for quantum science and technology, Université Paris-Saclay, 7/12/2019.
• Quantum computers: practical progress on this enormous undertaking, The Conversation, 4/10/2022.