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SUMMARY:Dynamical frames in gravity: observables\, locality and covariance
DTSTART:20230220T140000
DTEND:20230220T150000
DTSTAMP:20260501T114855Z
UID:c83f1a5e842e5a571b7583941e676124dedd9908fd8d2acb36d12eba
CATEGORIES:Conferences - Seminars
DESCRIPTION:Philipp Höhn (Okinawa Institute of Science and Technology)\nA
 bstract: The notion of locality seems a priori in conflict with the gauge 
 symmetries of gravitational theories -- i.e. a group of diffeomorphisms --
 \, which move spacetime points around. A means of addressing this issue is
  to invoke dynamical reference frames\, which provide field-dependent coor
 dinatizations of spacetime. In this talk\, I will describe a completely ge
 neral framework for constructing such dynamical frames and their associate
 d relational observables in generally covariant theories. These observable
 s describe the remaining degrees of freedom in a gauge-invariant manner re
 lative to the frame and give rise to a relational notion of locality\, bas
 ed on the relationships between fields. Our framework unifies previous app
 roaches and naturally comes with the notion of relational atlases and dyna
 mical frame transformations that permit us to change between arbitrary rel
 ational frame perspectives. This can be viewed as establishing a genuinely
  relational -- and thus arguably more physical -- update of the usual noti
 on of general covariance. I will then comment on how dynamical frames can 
 be used to establish microcausality for gravitational observables and to d
 efine subsystems (i.e. subregions) in a gauge-invariant manner. 
LOCATION:BSP 727 https://plan.epfl.ch/?room==BSP%20727
STATUS:CONFIRMED
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