David Wallace, Quantum Gravity at Low Energies. QISS Seminar.

Abstract: I provide a conceptually-focused presentation of `low-energy quantum gravity’ (LEQG), the effective quantum field theory obtained from general relativity and which provides a well-defined theory of quantum gravity at energies well below the Planck scale. I emphasize the extent to which some such theory is required by the abundant observational evidence in astrophysics and cosmology for situations which require a simultaneous treatment of quantum-mechanical and gravitational effects, \emph{contra} the often-heard claim that all observed phenomena can be accounted for either by classical gravity or by non-gravitational quantum mechanics, and I give a detailed account of the way in which a treatment of the theory as fluctuations on a classical background emerges as an approximation to the underlying theory rather than being put in by hand. I discuss the search for a Planck-scale quantum-gravity theory from the perspective of LEQG and give an introduction to the Cosmological Constant problem as it arises within LEQG. ---------------------------------------------------------------------------------------------------------- For announcements of upcoming seminars you can visit http://www.qiss.fr/virtual-seminars.html or join our mailing list through https://groups.google.com/forum/#!for.... ---------------------------------------------------------------------------------------------------------- About QISS The Quantum Information Structure of Spacetime (http://www.qiss.fr) is an interdisciplinary research initiative among several universities and research institutes all over the world, supported by the John Templeton Foundation through the grant https://www.templeton.org/grant/the-q... , coordinated from The Samy Maroun Center for Space, Time and the Quantum (http://www.spacetimeandquantum.com). The goal of QISS is to explore and connect the research domains of Quantum Information/Computing, Quantum Gravity and Quantum Foundations. Main objectives are to found the physics of quantum spacetime on an information-theoretic basis, to bring within reach empirical access to quantum gravity in 'table-top' laboratory conditions by exploiting rapid advances in quantum computing related technologies and using quantum information theoretic concepts, and to promote an extensive interaction between physicists and philosophers on the conceptual role of information in spacetime physics.