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SUMMARY:An introduction to quantum reference frames and their application 
 in gauge theory and gravity
DTSTART:20250227T100000
DTEND:20250227T120000
DTSTAMP:20260406T160001Z
UID:b7da19aa94e02bf0aa16de071e2d4b0e03f1647c4ec283774bce0a5f
CATEGORIES:Conferences - Seminars
DESCRIPTION:Philipp Höhn\nQuantum reference frames (QRFs) are a universal
  tool for dealing with symmetries in quantum theory. While they originated
  in the foundations of quantum theory and quantum information\, they are p
 articularly useful in theories with gauge symmetries\, where they define a
  split between redundant and non-redundant information. Broadly\, QRFs cor
 respond to the degrees of freedom that one fixes in a gauge fixing procedu
 re or\, equivalently\, employs to dress non-invariant operators into invar
 iant ones.\nIn this lecture\, I will introduce QRFs and explain how their 
 identification in gauge systems as frames for the pertinent gauge group le
 ads to novel relational insights into gauge-invariant descriptions\, core 
 of which is a covariance under changes of QRFs. This leads to a QRF-depend
 ence of entanglement\, thermal properties and more generally of gauge-inva
 riant definitions of subsystem partitions. For illustration\, I will then 
 apply this to perturbative quantum gravity and clarify how the recent stor
 y about “observers” in gravitational algebras by Witten et al. is one 
 about QRFs.\nDepending on interest and time\, I may also explain what edge
  modes and finite regions in gauge theory and gravity have to do with QRFs
  and/or how QRFs permit to establish a correspondence between (group-based
 ) quantum error correction and gauge theories.\n 
LOCATION:BSP 727
STATUS:CONFIRMED
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