[institut] [phys4phys] Group for Gravitation, Particle and Fields on-line seminar, Wednasday 27 October 2021

[Marija Dimitrijevic Ciric]

Dear colleagues,

You are cordially invited to the online seminar of the Group for 
Gravitation, Particles and Fields, which will be held (note the unusual 
date and time) on Wednesday, 27 October 2021 at 13:00 via the 
BigBlueButton platform (link is given below).


The talk entitled

How the Immirzi Parameter deforms the SL(2,R) Boundary Symmetries on the 
Light Cone

will be given by Wolfgang Martin Wieland (AUSTRIAN ACADEMY OF SCIENCES, 
INSTITUTE FOR QUANTUM OPTICS AND QUANTUM INFORMATION VIENNA).

Abstract: This talk describes how the Barbero--Immirzi parameter deforms 
the SL(2,R) symmetries on a null surface boundary. Our starting point is 
the definition of the action and its boundary terms. The action that we 
use is the usual Holst action. Compared to metric gravity it contains an 
additional coupling constant -- the Barber Immirzi parameter. Given the 
action and the boundary conditions, we introduce the covariant phase 
space and explain how the Holst term alters the boundary symmetries on a 
null surface. This alteration only affects the algebra of the edge modes 
on a cross-section, whereas the algebra of the radiative modes is 
unchanged by the addition of the Barbero--Immirzi parameter. To compute 
the Poisson brackets explicitly, we work on an auxiliary phase space, 
where the SL(2,R) symmetries of the boundary fields are manifest. The 
physical phase space is obtained by imposing both first-class and 
second-class constraints. All gauge generators are at most quadratic in 
terms of the fundamental SL(2,R) variables. Finally, we discuss various 
strategies to quantise the system.
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Time: October 27, 2021 13:00 Belgrade

https://gravityserver.ipb.ac.rs/b/mar-xoo-t1v-vwn

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Best regards,

Marija Dimitrijevic Ciric

University of Belgrade
Faculty of Physics
Studentski trg 12-16
11000 Belgrade
Serbia