BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//talks.cam.ac.uk//v3//EN
BEGIN:VTIMEZONE
TZID:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19700329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19701025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CATEGORIES:CQIF Seminar
SUMMARY:Self-testing of binary observables based on commut
ation - Jed Kaniewski
DTSTART;TZID=Europe/London:20170323T141500
DTEND;TZID=Europe/London:20170323T151500
UID:TALK70786AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/70786
DESCRIPTION:In this talk we consider the problem of certifying
binary\nobservables based on a Bell inequality vi
olation alone\, a task known as\nself-testing of m
easurements. We introduce a family of commutation-
\nbased measures\, which encode all the distinct a
rrangements of two\nprojective observables on a qu
bit. These quantities by construction\ntake into a
ccount the usual limitations of self-testing and s
ince they\nare `weighted' by the (reduced) state\,
they automatically deal with\nrank-deficient redu
ced density matrices. We show that these measures\
ncan be estimated from the observed Bell violation
in several scenarios.\nThe trade-offs turn out to
be tight and\, in particular\, they give non-\ntr
ivial statements for arbitrarily small violations.
On the other\nextreme\, observing the maximal vio
lation allows us to deduce precisely\nthe form of
the observables\, which immediately leads to a com
plete\nrigidity statement. In particular\, we show
that the n-partite Mermin-\nArdehali-Belinskii-Kl
yshko inequality self-tests the n-partite\nGreenbe
rger-Horne-Zeilinger state and maximally incompati
ble qubit\nmeasurements on every site for all n. O
ur results imply that any pair\nof projective obse
rvables on a qubit can be certified in a robust\nm
anner. Finally\, we show that commutation-based me
asures give a\nconvenient way of expressing relati
ons between more than two\nobservables. This talk
is based on https://arxiv.org/abs/1702.06845 .
LOCATION:MR5\, Centre for Mathematical Sciences\, Wilberfor
ce Road\, Cambridge
CONTACT:Steve Brierley
END:VEVENT
END:VCALENDAR