ELFT HÍRADÓ

[Janos Asboth <asboth.janos AT ttk.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

márc. 8. péntek 10h15,

1111 Budapest, Budafoki út 8., BME F III. magasföldszint 01.,
Elméleti Fizika Tanszék szemináriumi szoba

Trényi Róbert  (UPV Bilbao/Wigner FK)
Activation of metrologically useful genuine multipartite entanglement

The metrological usefulness of a quantum state can be measured by the
amount it outperforms the most useful fully separable state. It is known
that maximal metrological usefulness necessitates genuine multipartite
entanglement (GME). In contrast, however, not all GME states exhibit
utility for metrology. In this work[1], to make non-useful entangled states
useful we consider an activation scheme by employing multiple copies of the
state. With this scheme, we identify a broad class of practically important
GME states that can attain the maximal metrological performance in the
limit of many copies, even though in the single copy case these states can
be non-useful. Thus, we essentially activate quantum metrologically useful
GME. Moreover, this maximal usefulness is reached exponentially fast with
the number of copies and the necessary measurements are simple correlation
observables. We also provide examples of states not living in the above
mentioned class that improve their usefulness. Our scheme can also be used
to protect certain quantum states against certain types of errors without
the use of full-fledged quantum error correction techniques.

[1] R Trényi, Á Lukács, P Horodecki, R Horodecki, T Vértesi, G Tóth, New J.
Phys. 26 023034 (2024)

Minden érdeklődőt szeretettel várunk.
Asbóth János,
 szemináriumi koordinátor