Over the last two decades there has been an impressive progress in many-body quantum technologies. However, we do not yet have practical certification tools that allow us, in general, to ensure that the experimental quantum devices built actually work properly. In fact, since classical simulations of many-body quantum systems is a computationally difficult task the usual scientific paradigm of “predicting and comparing with the experiment” becomes inapplicable. The biggest challenge is to ensure that quantum machines with the declared goal of solving classically intractable problems really work properly. In this colloquium, I will speak about recent advances in both the direct certification and the characterisation of experimental many-body quantum state preparations. In particular, in the first half of the colloquium, I will briefly review fidelity witnesses for bosonic quantum simulations and present two recent applications of them: delegated continuous-variable quantum computation and quantum simulations of spin-1/2 chains. Then, in the second half, I will elaborate on a recently-developed technique for quantum state reconstruction assisted by (classical) probabilistic generative models originally native of unsupervised machine learning.


Seminar, June 26, 2019, 14:30. ICFO’s Seminar Room

Hosted by Prof. Antonio Acín