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Quantum Computing

Published on 1 October 2020

Towards large-scale quantum computers with silicon quantum bits

 What's quantum computing?

  • Founded in 2018, the Quantum Silicon Grenoble consortium brings together CEA-Leti / IRIG, CNRSNéel Institute, and UGA researchers, working towards the development of a 100-qubit processor. In an early success, the group encapsulated a single electron in a silicon circuit leveraging silicon-based CMOS technology. When this single electron reaches its quantum state, it is oriented towards the north and south magnetic poles at the same time. That is called a "state superposition".

  • When a superposition is reached, a qubit takes simultaneously both 0 and 1 values, unlike conventional bits, which can only take one of these values at a time.This physical phenomenon helps boost computing capacity of quantum computers exponentially, compared to conventional computers.


The strength of quantum technology resides in the intrinsic parallelism of operations which, wisely used with specific algorithms, enables an exponential acceleration of computations, compared to current computers. Ultimately, quantum computing is likely to bring improvements within various areas, including:

  • Simulation: i.e. helping to identify the best drug to eliminate viruses, bacteria or cure cancers; improving physics and materials science.
  • Machine learning and Big Data: Developing autonomous vehicles, improving traffic, weather and financial forecasts, mathematical calculations, etc.
  • Cybersecurity: cryptography, especially.

 The choice of silicon

There are four main ways to develop a quantum computer:

  • superconductors
  • photonics
  • trapped ions
  • electron spin within semiconductors (silicon)

The consortium has based its research on silicon because of its size, reliability, speed and operating temperature. So far, it is the only group of researchers that has demonstrated quantum operations in an electron spin system, trapped in a quantum circuit, leveraging standard microelectronics. Each member of the consortium brings the necessary skills and expertise for the development of a quantum computer:

  • CEA-Leti: microelectronics manufacturing technologies, circuit and system design
  • CEA-IRIG (Interdisciplinary Research Institute of Grenoble): quantum properties of silicon-based nanostructures and measurements at very low temperatures
  • CNRS (National Centre for Scientific Research) Néel Institute: quantum manipulation of individual objects
  • UGA (Université Grenoble Alpes): quantum algorithms close to hardware.

 What's next?

  • In 2018, the consortium developed the world's first silicon qubit with CMOS technology. The next major steps will be the demonstration of 6 qubits in 2021, then 100 qubits in 2024.

  • Many hurdles remain to be overcome. These include degrees of latitude, interactions, quality of materials, and number of connections between qubits, addressing methods, measurement methods, de-coherence, low-temperature control electronics, emission of control signals at room temperature, implementation of error-correcting codes, programming constraints, etc.

Key facts

  • ERC Synergy, 2018, Tristan Meunier (Néel Institute, CNRS), Silvano de Franceschi (CEA-IRIG), Maud Vinet (CEA-Leti)
  • Leadership of the QLSI project within the Quantum Flagship. Goal is to deliver a demonstrator featuring 16 qubits in 2024.
  • A dozen patents in a rapidly growing portfolio


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