Universität zu Köln

Journal Article

Albarran, Imanol ORCID: 0000-0003-4278-9372, Bouhmadi-Lopez, Mariam ORCID: 0000-0002-1529-1889, Kiefer, Claus ORCID: 0000-0001-6163-9519, Marto, Joao ORCID: 0000-0003-3974-9177 and Moniz, Paulo Vargas (2016). Classical and quantum cosmology of the little rip abrupt event. Phys. Rev. D, 94 (6). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2470-0029

Barton, Simon, Kiefer, Claus, Kleihaus, Burkhard and Kunz, Jutta (2022). Symmetric wormholes in Einstein-vector-Gauss-Bonnet theory. Eur. Phys. J. C, 82 (9). NEW YORK: SPRINGER. ISSN 1434-6052

Bouhmadi-Lopez, Mariam ORCID: 0000-0002-1529-1889, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Kraemer, Manuel (2014). Resolution of type IV singularities in quantum cosmology. Phys. Rev. D, 89 (6). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1550-2368

Bouhmadi-López, Mariam, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Martín-Moruno, Prado ORCID: 0000-0001-8073-4896 (2019). Phantom singularities and their quantum fate: general relativity and beyond—a CANTATA COST action topic. General Relativity and Gravitation, 51 (10). Springer. ISSN 0001-7701

Brizuela, David, Kiefer, Claus and Kramer, Manuel ORCID: 0000-0002-4442-277X (2016). Quantum-gravitational effects on gauge-invariant scalar and tensor perturbations during inflation: The de Sitter case. Phys. Rev. D, 93 (10). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2470-0029

Brizuela, David, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Kramer, Manuel ORCID: 0000-0002-4442-277X (2016). Quantum-gravitational effects on gauge-invariant scalar and tensor perturbations during inflation: The slow-roll approximation. Phys. Rev. D, 94 (12). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2470-0029

Brizuela, David, Kiefer, Claus, Krämer, Manuel and Robles-Pérez, Salvador (2019). Quantum-gravity effects for excited states of inflationary perturbations. Physical Review D, 99 (10). APS. ISSN 2470-0010

Calcagni, Gianluca ORCID: 0000-0003-2631-4588, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Steinwachs, Christian F. (2014). Quantum cosmological consistency condition for inflation. J. Cosmol. Astropart. Phys. (10). BRISTOL: IOP PUBLISHING LTD. ISSN 1475-7516

Eckart, Andreas, Hüttemann, Andreas, Kiefer, Claus, Britzen, Silke, Zajaček, Michal, Lämmerzahl, Claus, Stöckler, Manfred, Valencia-S, Monica, Karas, Vladimir and García-Marín, Macarena (2017). The Milky Way’s Supermassive Black Hole: How Good a Case Is It? Foundations of Physics, 47 (5). pp. 553-624. Springer. ISSN 0015-9018

Eingorn, Maxim ORCID: 0000-0002-1545-7818 and Kiefer, Claus ORCID: 0000-0001-6163-9519 (2015). Scalar perturbations in cosmological models with dark energy-dark matter interaction. J. Cosmol. Astropart. Phys. (7). BRISTOL: IOP PUBLISHING LTD. ISSN 1475-7516

Eingorn, Maxim, Kiefer, Claus and Zhuk, Alexander (2017). Cosmic screening of the gravitational interaction. International Journal of Modern Physics D, 26 (12). p. 1743012. World Scientific. ISSN 0218-2718

Eingorn, Maxim, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Zhuk, Alexander (2016). Scalar and vector perturbations in a universe with discrete and continuous matter sources. J. Cosmol. Astropart. Phys. (9). BRISTOL: IOP PUBLISHING LTD. ISSN 1475-7516

Hehl, Friedrich W. and Kiefer, Claus (2018). Comparison of the DeWitt metric in general relativity with the fourth-rank constitutive tensors in electrodynamics and in elasticity theory. General Relativity and Gravitation, 50 (1). Springer. ISSN 0001-7701

Kamenshchik, Alexander, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Kwidzinski, Nick (2016). Classical and quantum cosmology of Born-Infeld type models. Phys. Rev. D, 93 (8). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1550-2368

Kiefer, Claus (2010). Can Quantum Theory be Applied to the Universe as a Whole? Found. Phys., 40 (9-10). S. 1410 - 1419. NEW YORK: SPRINGER. ISSN 0015-9018

Kiefer, Claus ORCID: 0000-0001-6163-9519 (2014). Concept of Law in Physics On the Concept of Law in Physics. Eur. Rev., 22. S. S26 - 7. CAMBRIDGE: CAMBRIDGE UNIV PRESS. ISSN 1474-0575

Kiefer, Claus (2019). Does the quantum mechanical wave function exist? Zagadnienia Filozoficzne Nauce (66). S. 111 - 129. KRAKOW: COPERNICUS CENTER PRESS. ISSN 2451-0602

Kiefer, Claus (2012). Emergence of a classical Universe from quantum gravity and cosmology. Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci., 370 (1975). S. 4566 - 4576. LONDON: ROYAL SOC. ISSN 1364-503X

Kiefer, Claus and Kraemer, Manuel (2012). CAN EFFECTS OF QUANTUM GRAVITY BE OBSERVED IN THE COSMIC MICROWAVE BACKGROUND? Int. J. Mod. Phys. D, 21 (11). SINGAPORE: WORLD SCIENTIFIC PUBL CO PTE LTD. ISSN 1793-6594

Kiefer, Claus and Kwidzinski, Nick (2019). Singularity avoidance in anisotropic quantum cosmology. Journal of Physics: Conference Series, 1275. 012011. IOP. ISSN 1742-6588

Kiefer, Claus, Kwidzinski, Nick and Piechocki, Włodzimierz (2018). On the dynamics of the general Bianchi IX spacetime near the singularity. The European Physical Journal C, 78 (9). Springer. ISSN 1434-6044

Kiefer, Claus, Kwidzinski, Nick and Piontek, Dennis (2019). Singularity avoidance in Bianchi I quantum cosmology. The European Physical Journal C, 79 (8). Springer. ISSN 1434-6044

Kiefer, Claus and Nikolić, Branislav (2017). Conformal and Weyl-Einstein gravity: Classical geometrodynamics. Physical Review D, 95 (8). 084018. APS. ISSN 2470-0010

Kiefer, Claus and Nikolić, Branislav (2017). Quantum geometrodynamics of Einstein and conformal (Weyl-squared) gravity. Journal of Physics: Conference Series, 880. 012002. IOP. ISSN 1742-6588

Kiefer, Claus ORCID: 0000-0001-6163-9519 and Peter, Patrick ORCID: 0000-0002-7136-8326 (2022). Time in Quantum Cosmology. Universe, 8 (1). BASEL: MDPI. ISSN 2218-1997

Kiefer, Claus and Sandhoefer, Barbara (2022). Quantum cosmology. Z. Naturfors. Sect. A-J. Phys. Sci., 77 (6). S. 543 - 560. BERLIN: WALTER DE GRUYTER GMBH. ISSN 1865-7109

Kiefer, Claus and Schmitz, Tim (2019). Singularity avoidance for collapsing quantum dust in the Lemaître-Tolman-Bondi model. Physical Review D, 99 (12). ISSN 2470-0010

Kiefer, Claus ORCID: 0000-0001-6163-9519 and Vardanyan, Tatevik (2022). Power spectrum for perturbations in an inflationary model for a closed universe. Gen. Relativ. Gravit., 54 (4). NEW YORK: SPRINGER/PLENUM PUBLISHERS. ISSN 1572-9532

Kiefer, Claus ORCID: 0000-0001-6163-9519 and Wichmann, David (2018). Semiclassical approximation of the Wheeler–DeWitt equation: arbitrary orders and the question of unitarity. General Relativity and Gravitation, 50 (6). Springer. ISSN 0001-7701

Menezes, Gabriel, Kiefer, Claus and Marino, Jamir (2017). Thermal and nonthermal scaling of the Casimir-Polder interaction in a black hole spacetime. Physical Review D, 95 (8). 085014. APS. ISSN 2470-0010