Learning mixed quantum states in large-scale experiments

by Prof. Benoît Vermersch (Université Grenoble Alpes & Quobly)

Wednesday 15 Oct 2025, 10:00 → 11:00 Europe/Zurich

ODRA/111

The randomized measurements toolbox is now routinely used in quantum experiments to estimate fundamental quantum properties, such as entanglement [1].

While experimentalists appreciate the simplicity and robustness aspects of such measurement protocols, a challenge for theorists is to design strategies for overcoming statistical errors using `cheap' polynomial resources in system size.

 

In this context, I will present recent upgrades to the randomized measurements toolbox that address this challenge for large-scale quantum states that are relevant to the field of quantum simulation. In particular, I will discuss efficient protocols for measuring entanglement [2] and performing state tomography [3]. 

 

[1] A. Elben, S. T. Flammia, H.-Y. Huang, R. Kueng, J. Preskill, B. Vermersch, and P. Zoller, The Randomized Measurement Toolbox, Nat Rev Phys 5, 9 (2022).

[2] B. Vermersch, M. Ljubotina, J. I. Cirac, P. Zoller, M. Serbyn, and L. Piroli, Many-Body Entropies and Entanglement from Polynomially Many Local Measurements, Phys. Rev. X 14, 031035 (2024).

[3] M. Votto, M. Ljubotina, C. Lancien, J. Ignacio Cirac, P. Zoller, M. Serbyn, L. Piroli, B. Vermersch,  arXiv:2507.12550