München 2019 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 8: Quantum Cosmology and Quantum Gravity I

GR 8.5: Talk

Wednesday, March 20, 2019, 15:30–15:45, HS 4

Dynamics of Dirac observables in canonical cosmological perturbation theory — •David Winnekens and Kristina Giesel — University of Erlangen-Nürnberg, Institute for Quantum Gravity, Institute for Quantum Gravity, Staudtstr. 7, 91058 Erlangen

Canonical cosmological perturbation theory describes a Hamiltonian framework for cosmology. Ultimately, a link to the standard Lagrangian treatment is of interest. Proceeding into this direction, Pons et al [1] chose the extended ADM phase space as natural footing that allows for a complete treatment of cosmological gauges that also rely on perturbations of lapse and shift, as it treats them not only as Lagrange multipliers but as dynamical variables. A recent approach [2] generalized their formalism by using geometrical clocks as reference fields and constructing gauge invariant Dirac observables for all conjugate pairs of metric and matter perturbations. Choosing specific clocks corresponds to different Gauge fixings and thereby lead naturally to the respective gauge invariant variables. These are the Bardeen potential for the longitudinal gauge and the Mukhanov-Sasaki variable for the spatially flat gauge. We also present an efficient method to obtain the second order evolution equations of these variables and find accordance with the literature at linear order.

[1] J. M. Pons, D. C. Salisbury and K. A. Sundermeyer. Phys. Rev. D, 80:084015, 2009 & J. Phys.: Conf. Ser., 222, 2010 [2] K. Giesel, A. Herzog. Int. J. Mod. Phys., D27(08):1830005, 2018; K. Giesel, A. Herzog and P. Singh. Class. Quant. Grav., 35(15):155012, 2018 & K. Giesel, P. Singh and D. Winnekens. https://arxiv.org/abs/1811.07972