ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI SeminarFrancesco PretiForschungszentrum Jülich, Németország (host: Kiss 
Tamás)Statistical evaluation and optimization of entanglement purification 
protocolsTuesday, 18 June 2024, 10:00, KFKI Campus, Bldg. 1, 2nd floor, 
Conference RoomWe introduce a quantitative characterization of two-qubit 
entanglement purification protocols based on the amount of entanglement they 
can retain/destroy. Our approach uses concurrence and the hit-and-run Monte 
Carlo algorithm applied to the convex set of all two-qubit states. We 
demonstrate that pioneering protocols are unable to improve the estimated 
initial average concurrence of almost uniformly sampled density matrices, 
however, as it is known,they still generate pairs of qubits in a state that 
is close to a Bell state. We also develop a more efficient protocol and 
investigate it numerically together with a recent proposal based on an 
entangling rank-two projector. Furthermore, we present a class of variational 
purification protocols with continuous parameters and optimize their output 
concurrence. These optimized algorithms turn out to surpass former proposals 
and our new protocol by means of not wasting too many entangled 
states. Minden érdeklődőt szívesen látunk! - Everyone is welcome to 
attend.Attila Nagysem-admin AT szfki.hu