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CATEGORIES:CQIF Seminar
SUMMARY:Anomalous Distillation of Metrological Quantum Inf
ormation - David Arvidsson Shukur\, Hitachi Cambri
dge Laboratory
DTSTART;TZID=Europe/London:20220310T141500
DTEND;TZID=Europe/London:20220310T151500
UID:TALK170819AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/170819
DESCRIPTION:Quantum experiments that involve post-selection or
filtering have generated heated debate over the l
ast decades— from a foundational and a practical p
erspective. Pre- and post-selected expectation val
ues of a weakly measured observable can lie outsid
e an observable’s eigenspectrum. Classical theorie
s cannot explain this. In this talk\, I investigat
e post-selection within the framework of single- a
nd multi-parameter quantum learning.\n\nQuantum le
arning (in metrology and machine learning) involve
s estimating unknown parameters 𝜽 = (𝜃_1\, 𝜃_2\,…
\, 𝜃_𝑀) from measurements of quantum states 𝜌_𝜽. T
he quantum Fisher information matrix can bound the
average amount of information learnt about 𝜽 per
experimental trial. In several scenarios\, it is a
dvantageous to concentrate information in as few s
tates as possible\, for example\, to avoid detecto
r saturation. Here\, we present a “go-go” theorem
proving the possibility of unbounded and lossless
distillation of Fisher information about multiple
parameters in quantum learning. That is\, there is
no cap on how much quantum information can be dis
tilled into a subset of quantum particles. My\, an
d collaborators’\, results enable the construction
of filters that can reduce arbitrarily the number
of quantum states\, whilst retaining all initial
information. The fundamental resource underlying t
his unbounded information distillability\, I will
show\, is Kirkwood-Dirac negativity\, a narrower n
on-classicality concept than non-commutation.\n\nT
he recipe for lossless and unbounded distillation
of quantum information\, extends pre- and post-sel
ected techniques of weak-value amplification to th
e growing fields of quantum machine learning and q
uantum metrology. If time permits\, I will describ
e a proof-of-principle experiment where collaborat
ors and I demonstrate how the use of quantum-filte
ring can boost the information content of single p
hotons about an unknown polarisation rotation by a
factor of over 200.\n\nReferences:\n[1] https://w
ww.nature.com/articles/s41467-020-17559-w\n[2] htt
ps://arxiv.org/abs/1811.08046\n[3] https://arxiv.o
rg/abs/2111.01194\n[4] https://iopscience.iop.org/
article/10.1088/1751-8121/ac0289
LOCATION:MR2 Centre for Mathematical Sciences
CONTACT:Damian Pitalua-Garcia
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