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FAU^2 Focus Workshop on quantum black holes and the relation to asymptotic infinity

25–27 Jun 2024
ECAP Laboratory Building
Europe/Berlin timezone

Contribution List

26 out of 26 displayed
  1. 8. Axial perturbations in hybrid Loop Quantum Cosmology
    Guillermo A. Mena Marugán (Instituto de Estructura de la Materia, CSIC)
    25/06/2024, 13:30
    Talk
    Session 1

    There is a growing interest in investigating homogeneous but anisotropic spacetimes owing to their relation with nonrotating, uncharged black hole interiors. In this context, we present a description of axial perturbations in Kantowski-Sachs spacetimes with a massless scalar field. We truncate the action at the quadratic perturbative order. Perturbations are expressed in terms of perturbative...

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  2. 10. A testable prediction from LQG?  20μg bound-states
    Carlo Rovelli (Zoom) (Aix-Marseille University)
    25/06/2024, 14:10
    Talk
    Session 1

    The life of a black hole is dominated by dissipative effects, hard to model exactly. I discuss their effects on the full life of a blackhole and its while hole remnant.

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  3. 27. Phenomenology of black hole remnants in the early universe
    Francesca Vidotto (Western University)
    25/06/2024, 14:50

    Understanding the properties of remnants resulting from the exhaustion of black holes can open new frontiers for quantum gravity phenomenology, both in terms of direct and indirect detection. In my talk,  I examine different possible ways in which black hole remnants may manifest their self in the early universe. I discuss possible constraints as well as possible desirable effects in relation...

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  4. 15. Reissner–Nordström black holes in LQG: the improved dynamics
    Javier Olmedo (Zoom) (Universidade de Granada)
    25/06/2024, 15:30

    In this talk we will discuss the quantization of a charged black hole within the improved dynamics of loop quantum gravity and several properties of its semiclassical effective geometries. Adopting a redefined scalar constraint, that renders the algebra of constraints into a Lie algebra, we apply loop quantum gravity techniques adhered to a novel improved dynamics scheme. The model is...

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  5. 31. Final discussion with all speakers of session 1
    25/06/2024, 16:10
  6. 9. Non-perturbative quantisation of impulsive radiative data
    Wolfgang Wieland (FAU Erlangen-Nürnbreg)
    25/06/2024, 17:10
    Talk
    Session 2

    This talk gives a broad introduction into an emerging field at the interface of quantum foundations and quantum gravity. What connects these different research areas are common questions of shared interest: What is the causal structure at the quantum level? What is the role of the equivalence principle at the quantum level? Are the reference frames classical or quantum? After a brief...

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  7. 36. Canonical structure, Dressing time and and quantization of null geometry.
    Laurent Freidel (Zoom) (Perimeter Institute )
    25/06/2024, 17:50

    In this talk, I will review our recent work with L. Ciambelli and R. Leigh, focusing on the non-perturbative characterization of the gravitational phase space along null boundaries.

    I will present the construction of the Carrollian curved geometry, the Poisson bracket and discuss the construction of a field-dependent time called dressing time that allows the construction of a positive...

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  8. 14. Spherical collapse and black hole evaporation
    Madhavan Varadarajan (Zoom) (RRI)
    25/06/2024, 18:30

    We consider spherically symmetric gravity coupled to a spherically symmetric scalar field with a specific coupling which depends on the Areal Radius. Suitable boundary conditions ensure the existence of an axis of symmetry and consequently a single asymptotic past and future (as opposed to a pair of left and right ones). The scalar field stress energy takes the form of null dust. Its classical...

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  9. 29. Final discussion with all speakers of session 2
    25/06/2024, 19:10
  10. 16. Isolated horizon state-counting in the presence of matter
    Hanno Sahlmann (Friedrich-Alexander-Universität Erlangen Nürnberg (FAU))
    26/06/2024, 13:30

    I will review some older results on counting states and calculating the entropy of isolated horizons in loop quantum gravity in the presence of charges/matter fields on the horizon. One question that I will answer at least partially in some examples is if the matter DOF contribute to the entropy, and if so, to what order.
    I will also briefly touch on some newer results and work in progress...

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  11. 20. Entanglement, soft modes and an infrared on-shell action in asymptotically flat spacetimes
    Ana-Maria Raclariu (Zoom) (Department of Mathematics, King's College London.)
    26/06/2024, 14:10

    In this talk I will show that edge modes in free Maxwell theory in 3+1 dimensions lead to correlated fluctuations in the large gauge charges of a subregion and its complement, and result in a non-trivial contribution to the entanglement entropy across a cut of future null infinity. I will then outline a generalization of these ideas to gravity. In particular, I will highlight a novel relation...

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  12. 25. Conformal Einstein's equations
    Wojciech Kaminski (University of Warsaw)
    26/06/2024, 14:50

    Einstein field equations are not conformally invariant. Despite this fact, conformal geometry plays an important role in description of asymptotics of the solutions via Penrose conformal compactification. Moreover, in many cases such conformal compactification of solution is smooth. It turns out that these facts are linked to a fundamental object in conformal geometry, Fefferman-Graham...

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  13. 30. Final discussion with speakers of session 3
    26/06/2024, 15:30
  14. 11. Quantum Field Theory of Black Hole Perturbations
    Thomas Thiemann (FAU Erlangen-Nuremberg)
    26/06/2024, 16:30
    Talk
    Session 4

    In order to increase our understanding of the black hole information loss paradox
    it appears mandatory to incorporate backreaction effects into the black hole evaporation process. We propose a natural extension of the well known linear,
    backreaction free, perturbation theory of black holes. The extended framework
    is based on the reduced phase space approach and therefore is able to...

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  15. 13. Entanglement of fields in evaporating black holes
    Beatriz Elizaga Navascués (Louisiana State University)
    26/06/2024, 17:10

    Understanding the quantum information aspects of fields in gravitational collapse scenarios remains an open issue to date. Here, we present a conservative QFT study about the entanglement structure of the Hawking effect in evaporating black holes. For this purpose, first we review the known concept of Hawking partners, as being the field modes that are entangled with, and thus purify, the...

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  16. 17. Is Planckian discreteness observable in cosmology?
    Alejandro Perez (Zoom) ( Centre de Physique Théorique )
    26/06/2024, 17:50

    A Planck scale inflationary era—in a quantum gravity theory predicting discreteness of quantum geometry at the fundamental scale—produces the scale invariant spectrum of inhomogeneities with very small tensor-to-scalar ratio of perturbations and a hot big bang leading to a natural dark matter genesis scenario. In this talk I evoke the possibility that some of the major puzzles in cosmology...

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  17. 32. Final discussion with all speakers of session 4
    26/06/2024, 18:30
  18. 23. Semiclassical and quantum black holes
    Jerzy Lewandowski (Zoom) (University of Warsaw)
    27/06/2024, 13:30

    TBA

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  19. 18. Spin foam amplitude of the black-to-white hole transition
    Cong Zhang (FAU Erlangen-Nürnberg)
    27/06/2024, 14:10

    It has been conjectured that quantum gravity effects may cause the black-to-white hole transition due to quantum tunneling. The transition amplitude of this process is explored within the framework of the spin foam model on a 2-complex containing 56 vertices. We develop a systematic way to construct the bulk triangulation from the boundary triangulation to obtain the 2-complex. By using...

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  20. 21. Criteria for Loop Quantization of Black Hole Systems
    Jonathan Engle (Zoom) (Florida Atlantic University)
    27/06/2024, 14:50

    Thus far, there is no proposal for a loop quantization -- even at the level of effective dynamics -- of Kantowski-Sachs that both is exactly covariant under residual diffeomorphisms and has the correct classical limit. The models of Chiou in 2008, Joe and Singh in 2015, and other models based on similar mu-bar schemes, are the former but not the latter. The model of Ashtekar, Olmedo, and Singh...

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  21. 33. Final discussion with all speakers of session 5
    27/06/2024, 15:30
  22. 12. Shell-crossings and shock formation during gravitational collapse
    Edward Wilson-Ewing (Zoom) (University of New Brunswick)
    27/06/2024, 16:30
    Talk
    Session 6

    Effective models of gravitational collapse in loop quantum gravity for the Lemaître-Tolman-Bondi spacetime predict that collapsing matter reaches a maximum finite density, bounces, and then expands outward. I will explain that in the marginally bound case, shell-crossing singularities commonly occur for inhomogeneous initial profiles of the dust energy density; this is the case in particular...

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  23. 39. Understanding shock waves in gravitational collapse
    Viqar Husain (Zoom) (University of New Brunswick)
    27/06/2024, 17:10

    Recent work on the gravitational collapse of dust with quantum gravity corrections provides evidence that black holes end in a shock wave. I will
    provide analytical evidence and describe the numerical procedure that leads to this conclusion.

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  24. 35. Generalized analysis of dust collapses in polymerized theory: non-marginally bound solutions, fate of shocks and covariance
    Hongguang Liu (FAU Erlangen)
    27/06/2024, 17:50

    Based on modifications inspired from loop quantum gravity (LQG), spherically symmetric models have recently been explored to understand the resolution of classical singularities and the fate of the spacetime beyond. While such phenomenological studies have provided useful insights, questions remain on whether such models exhibit some of the desired properties such as consistent LTB conditions,...

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  25. 34. Final discussion with all speakers of session 6
    27/06/2024, 18:30
  26. 37. Registration