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VERSION:2.0
PRODID:Icfo
X-PUBLISHED-TTL:P1W
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UID:69ed661774628
DTSTART:20230306T100000Z
SEQUENCE:0
TRANSP:OPAQUE
DTEND:20230306T110000Z
LOCATION:Seminar Room
SUMMARY:ICFO | RAVI KUNJWAL
CLASS:PUBLIC
DESCRIPTION:Measurements in quantum theory can fail to be jointly measurabl
 e. Like entanglement\, this incompatibility of measurements is necessary b
 ut not sufficient for violating Bell inequalities. The structure of (in)co
 mpatibility relations among a set of measurements can be represented by a 
 joint measurability structure\, i.e.\, a hypergraph with its vertices deno
 ting measurements and its hyperedges denoting all and only compatible sets
  of measurements. Since incompatibility is necessary for a Bell violation\
 , we also have that the joint measurability structure on each wing of the 
 Bell experiment must necessarily be non-trivial\, i.e.\, it must admit a s
 ubset of incompatible vertices. We show that for any non-trivial joint mea
 surability structure with a finite set of vertices\, there exists a quantu
 m realization with a set of measurements that enables a Bell violation\, i
 .e.\, given that Alice has access to this incompatible set of measurements
 \, there exists a set of measurements for Bob and an entangled state share
 d between them such that they can jointly violate a Bell inequality. We th
 us establish a qualitative equivalence between incompatibility and Bell no
 nlocality: a non-trivial joint measurability structure is not only necessa
 ry for a Bell violation\, but also sufficient. We also provide a character
 ization of some qubit measurements that are useful for Bell inequality vio
 lations in the simplest joint measurability structure of interest\, i.e.\,
  Specker's scenario\, which consists of three pairwise compatible but trip
 lewise incompatible measurements.\n(Joint work with S.A. Yadavalli and N. 
 Andrejic.)
DTSTAMP:20260426T011047Z
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