ELFT HÍRADÓ

[Balog Janos <balog.janos AT wigner.mta.hu>]

MTA Wigner FK RMI Elméleti Osztály Szemináriuma
Tisztelettel meghívjuk


                        Michal Oszmaniec
                       (ICFO, Barcelona)

  "Universal extensions of restricted classes of quantum operations -
              a group theoretical approach"


             címmel tartandó szemináriumára.

Abstract:
For numerous applications of quantum theory it is desirable to be able 
to apply arbitrary unitary operations on a given quantum system. 
However, in particular situations only a subset of unitary operations is 
easily accessible. This raises the question of what additional unitary 
gates should be added to a given gate-set in order to attain physical 
universality, i.e., to be able to perform arbitrary unitary 
transformation on the relevant Hilbert space. In this work, we study 
this problem for three paradigmatic cases of naturally occurring 
restricted gate-sets: (A) particle-number preserving  bosonic linear 
optics, (B) particle-number preserving fermionic linear optics, and (C) 
general (not necessarily particle-number preserving) fermionic linear 
optics. Using recently developed tools from group theory as well as from 
reachability and control theory [1,2] allows us to classify, in each of 
these scenarios, what sets of gates are generated, if an additional gate 
is added to the set of allowed transformations. This solves the 
universality problem completely for arbitrary number of particles and 
for arbitrary dimensions of the single-particle Hilbert space.

After the presentation of these results, I will show they can be useful 
in the context of quantum metrology [3] and for the model of quantum 
computation based on fermionic linear optics [4,5].

[1] A. Bouland, S. Aaronson, Phys. Rev. A 89, 062316 (2014)
[2] Z. Zimboras,  R. Zeier, T. Schulte-Herbruggen, D. Burgarth,  Phys. 
Rev. A 92, 042309 (2015)
[3] M. Oszmaniec, R. Augusiak, C. Gogolin, J. Kołodyński, A. Acin, and 
M. Lewenstein, Phys. Rev. X 6, 041044 (2016)
[4] Sergey Bravyi, Phys. Rev. A 73, 042313 (2006)
[5] F. de Melo, P. Ćwikliński, B. M. Terhal, New J. Phys. 15 013015 
(2013)



Helye: MTA Wigner FK RMI II.ép. Médiaterem
Ideje: 2017 május 5  péntek du. 14:00 óra



Szívesen látunk minden érdeklődőt.

                                            Balog János