Giuseppe Vitagliano, "Spin-squeezing, entanglement and quantum metrology in many-body systems", Dip. di Fisica

 

Aula Careri edificio Marconi CU013 - 1°Piano

Data 12.01.2026

Oratori:

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I will present recent results on entanglement detection and quantification with collective measurements in many-body systems and discuss some applications, especially in the context of quantum metrology.
 

First I will give an introduction into entanglement and the idea of 'spin squeezing', which was introduced in the context of metrology, and explain the relation between the two concepts. I will show how the original spin squeezing criterion can be seen as a witness of entanglement and how it can be generalized in several respects, also allowing to quantify multipartite entanglement in different types of experimentally-controlled many-body systems, such as atomic clouds or solid-state materials. These entanglement witnesses are based on variances of collective operators, which can be extracted from average two-body correlation functions, which is the reason why they find widespread application in many-body systems, where higher-order correlation functions are generally very challenging to characterize. In particular I will present exemplary applications of these criteria to quantify entanglement in experiments with cold or ultracold atomic gases, as well as photonic systems. In the final part, I will focus on some recent extensions and applications of these methods, in quantum sensing but also in characterizing entanglement across phases of matter beyond typical approaches.