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SUMMARY:Quantum Things 2 - The quantum monad on relational structures - Na
 dish de Silva (University of Cambridge)
DTSTART:20191115T140000Z
DTEND:20191115T150000Z
UID:TALK134608@talks.cam.ac.uk
CONTACT:Jean Pichon-Pharabod
DESCRIPTION:Note the unusual location.\n\nHomomorphisms between relational
  structures play a central role in finite model theory\, constraint satisf
 action and database theory. A central theme in quantum computation is to s
 how how quantum resources can be used to gain advantage in information pro
 cessing tasks. In particular\, non-local games have been used to exhibit q
 uantum advantage in boolean constraint satisfaction\, and to obtain quantu
 m versions of graph invariants such as the chromatic number. We show how q
 uantum strategies for homomorphism games between relational structures can
  be viewed as Kleisli morphisms for a quantum monad on the (classical) cat
 egory of relational structures and homomorphisms. We show a general connec
 tion between these notions and state-independent quantum realizations of s
 trong contextuality in the Abramsky-Brandenburger formulation of contextua
 lity. We use these results to exhibit a wide range of examples of contextu
 ality-powered quantum advantage\, and to unify several apparently diverse 
 strands of previous work. 
LOCATION:SS03
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