ELFT HÍRADÓ

[Király Beáta <kiraly.beata AT atomki.hu>]

Alternatives of entanglement depth and metrological entanglement criteria 

by Szalay Szilárd 
HUN-REN Wigner Research Centre for Physics > Institute for Solid State 
Physics and Optics > Theoretical Solid State Physics Department > Strongly 
Correlated Systems Research Group 



When: 2025-10-07 Tuesday 11:00 

Where: HUN-REN ATOMKI, nagyelőadó (Debrecen, Bem tér 18/c) 





Other information: 
Tea and cookies are offered 30 minutes before the seminar. 



Abstract: 


We show that the Quantum Fisher Information in quantum metrology, which can 
be bounded from below in experiments, provides a lower bound on the Average 
Size of Entangled Subsystems. This is a particular case of a new kind of 
multipartite entanglement criterion, restricting the relative weights of the 
pure states of different average sizes of entangled subsystems in the mixed 
state. We illustrate the strength of this convex criterion and compare it to 
the original metrological entanglement criterion given by the Entanglement 
Depth. 



Related publications: 
- Szalay Sz. Tóth G., [ https://doi.org/10.22331/q-2025-04-18-1718 | 
Alternatives of entanglement depth and metrological entanglement criteria ] , 
Quantum 9, Paper: 1718 , 50 p. (2025) 
- Szalay Sz., [ https://doi.org/10.22331/q-2019-12-02-204 | k-stretchability 
of entanglement and the duality of k-separability and k-producibility ] , 
Quantum 3, Paper: 204 , 25 p. (2019) 








--- 
Király Beáta, PhD 
HUN-REN ATOMKI / HUN-REN Atommagkutató Intézet 
C: 4026 Debrecen, Bem tér 18/c 
T: +36 52 509 200 
E: kiraly.beata AT atomki.hu 
W: [ http://www.atomki.hu/ | www.atomki.hu ]