Team : QI

Arrival date : 11/01/2018

Localisation :

Boîte courrier 169

Couloir 25-26, Étage 1, Bureau 104

4 place Jussieu

75252 PARIS CEDEX 05

FRANCE

**Supervision** : Damian MARKHAM

**Co-supervision** : PERDRIX Simon

In the last few years we have seen unprecedented advances in quantum information technologies. Already quantum key distribution systems are available commercially. In the near future we will see waves of new quantum devices, offering unparalleled benefits for security, communication, computation and sensing. A key question to the success of this technology is their verification and validation.
Quantum technologies encounter an acute verification and validation problem: On one hand, since classical computations cannot scale-up to the computational power of quantum mechanics, verifying the correctness of a quantum-mediated computation is challenging. On the other hand, the underlying quantum structure resists classical certification analysis.

This PhD will focus on developing methods for verification of quantum technologies, and the fundamental physical and mathematical frameworks behind these methods. The student will build on techniques developed by supervisors in LORIA and LIP6, based around the measurement based picture of quantum information.

The student will develop and extend notably two frameworks, the stabiliser framework and the ZX calculus (both partially developed by the supervisors) in order to explore how quanutm features that give an advantage in quantum technology an be certified. These will be used to tackle questions of optimisation, resource tradeoff and praticality in terms of implementation. The student will also consider extensions of these frameworks for the infinite dimensional implementation of quantum information known as Continuous Variables. The infinite dimesional case requires careful consideration as many finite dimensional results do not hold (for example continuity of entropy).

The student will start by developing these methods to understand the verification of sub-universal computations such as boson sampling, where experimental development is already reaching the stage of being beyond classical simulatability, where these techniques are required to see a quantum enhancement. After this the student will tackle braoder quantum information protocols such as delegated computation, sensing and communication.
The student will also be encouraged to consider practical implementation issues. The LIP6 group has strong collaborations with several experimental partners, which the student will have access to. We anticipate the development of proof of principal experiments to be derived from the student’s results.
The studentship will be split between LORIA and LIP6 with the student spending roughly equal time in both places.