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Tue, 25 Jul
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Visiting us:
Dr. Beatriz Elizaga de Navascues
Mon, 24 - Fri, 28 Jul
Affiliation: Instituto de Estructura de la Materia, CSIC
Room: 02.734 (phone: -28479)
Dr. Beatriz Elizaga de Navascues
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Group Seminar
Tue, 25 Jul (14:00 - 16:00)
Room: SR 01.683
Speaker: Prof. Klaus Mecke (FAU)
Wed, 26 Jul
>
Visiting us:
Dr. Beatriz Elizaga de Navascues
Mon, 24 - Fri, 28 Jul
Affiliation: Instituto de Estructura de la Materia, CSIC
Room: 02.734 (phone: -28479)
Dr. Beatriz Elizaga de Navascues
>
Visiting us:
Dr. Antonia Zipfel
Wed, 26 - Fri, 28 Jul
Affiliation: Florida Atlantic University, USA
Room: 02.734 (phone: -28479)
Dr. Antonia Zipfel
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Group Seminar
Wed, 26 Jul (16:00 - 18:00)
Room: SR 02.729
Speaker: Dr. Beatriz Elizaga de Navascues (Instituto de Estructura de la Materia, CSIC)
It is well known that linear canonical transformations are not generally implemented as unitary operators in QFT. Such transformations include the dynamics that arises from linear field equations on the background spacetime. This evolution is specially relevant in nonstationary backgrounds, where there is no time-translational symmetry that can be exploited to select a quantum theory. We investigate whether it is possible to find a Fock representation for the canonical anticommutation relations of a Dirac field, propagating on homogeneous and isotropic cosmological backgrounds, on the one hand, and on tridimensional conformally ultrastatic spacetimes, on the other hand, such that the field evolution is unitarily implementable. First, we restrict our attention to Fock representations that are invariant under the group of symmetries of the system. Then, we prove that there indeed exist Fock representations such that the dynamics is implementable as a unitary operator. Finally, once a convention for the notion of particles and antiparticles is set, we show that these representations are all unitarily equivalent.
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Group Seminar
Wed, 26 Jul (18:00 - 20:00)
Room: SR 02.729
Speaker: Dr. Antonia Zipfel (Florida Atlantic University, USA)
Symmetry reduction plays an important role in classical as well as quantum gravity. Due to the elimination of degrees of freedom, symmetry reduced models are often easier to quantise. However, by quantising the reduced models one suppresses quantum fluctuation around the corresponding symmetry sector from the very beginning. Furthermore, the relation of such models to full quantum gravity is often unclear. Building on a recent proposal for a quantum reduction to spherical symmetry, we investigate the relation between a quantisation of spherically symmetric general relativity and a quantum reduction of loop quantum gravity in the so-called radial gauge.
Thu, 27 Jul
>
Visiting us:
Dr. Beatriz Elizaga de Navascues
Mon, 24 - Fri, 28 Jul
Affiliation: Instituto de Estructura de la Materia, CSIC
Room: 02.734 (phone: -28479)
Dr. Beatriz Elizaga de Navascues
>
Visiting us:
Dr. Antonia Zipfel
Wed, 26 - Fri, 28 Jul
Affiliation: Florida Atlantic University, USA
Room: 02.734 (phone: -28479)
Dr. Antonia Zipfel
Fri, 28 Jul
>
Visiting us:
Dr. Beatriz Elizaga de Navascues
Mon, 24 - Fri, 28 Jul
Affiliation: Instituto de Estructura de la Materia, CSIC
Room: 02.734 (phone: -28479)
Dr. Beatriz Elizaga de Navascues
>
Visiting us:
Dr. Antonia Zipfel
Wed, 26 - Fri, 28 Jul
Affiliation: Florida Atlantic University, USA
Room: 02.734 (phone: -28479)
Dr. Antonia Zipfel
Mon, 31 Jul
Tue, 1 Aug
Wed, 2 Aug
Thu, 3 Aug
Fri, 4 Aug
Mon, 7 Aug

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