74 citations · 579 across the 34 of their papers we have counts for
16 papers · 1 filter
Relative Entropy in de Sitter is a Noether Charge
Markus Fröb, Albert Much, Kyriakos Papadopoulos
We compute the relative entropy between the vacuum and a coherent state for a massive scalar field in de Sitter spacetime, using Tomita-Takesaki modular theory and the Araki-Uhlman…
Non-commutative Geometry from Perturbative Quantum Gravity in de Sitter spacetime
Markus Fröb, William C. C. Lima, Albert Much +1
We show that a non-commutative structure arises naturally from perturbative quantum gravity in a de Sitter background metric. Our work builds on recent advances in the construction…
Non-commutative coordinates from quantum gravity
Markus B. Fröb, Albert Much, Kyriakos Papadopoulos
Local observables in (perturbative) quantum gravity are notoriously hard to define, since the gauge symmetry of gravity -- diffeomorphisms -- moves points on the manifold. In parti…
Synchronous coordinates and gauge-invariant observables in cosmological spacetimes
Markus B. Fröb, William C. C. Lima
We consider the relational approach to construct gauge-invariant observables in cosmological perturbation theory using synchronous coordinates. We construct dynamical synchronous c…
Non-commutative Geometry from Perturbative Quantum Gravity
Markus Fröb, Albert Much, Kyriakos Papadopoulos
Trying to connect a fundamentally non-commutative spacetime with the conservative perturbative approach to quantum gravity, we are led to the natural question: are non-commutative…
On well-posedness and algebraic type of the five-dimensional charged rotating black hole with two equal-magnitude angular momenta
Markus B. Fröb, Igor Khavkine, Tomáš Málek +1
We study various mathematical aspects of the charged rotating black hole with two equal-magnitude angular momenta in five dimensions. We introduce a coordinate system that is regul…
Cosmological Perturbations and Invariant Observables in Geodesic Lightcone Coordinates
Markus B. Fröb, William C. C. Lima
We consider a recent approach to the construction of gauge-invariant relational observables in gravity in the context of cosmological perturbation theory. These observables are con…
Approaches to linear local gauge-invariant observables in inflationary cosmologies
Markus B. Fröb, Thomas-Paul Hack, Igor Khavkine
We review and relate two recent complementary constructions of linear local gauge-invariant observables for cosmological perturbations in generic spatially flat single-field inflat…
Propagators for gauge-invariant observables in cosmology
Markus B. Fröb, William C. C. Lima
We make a proposal for gauge-invariant observables in perturbative quantum gravity in cosmological spacetimes, building on the recent work of Brunetti et al. [JHEP 08 (2016) 032].…
Gauge-invariant quantum gravitational corrections to correlation functions
Markus B. Fröb
A recent proposal for gauge-invariant observables in inflation [R. Brunetti et al., JHEP 1608 (2016) 032] is examined. We give a generalisation of their construction to general bac…
Green's functions and Hadamard parametrices for vector and tensor fields in general linear covariant gauges
Markus B. Fröb, Mojtaba Taslimi Tehrani
We determine the retarded and advanced Green's functions and Hadamard parametrices in curved spacetimes for linearized massive and massless gauge bosons and linearized Einstein gra…
Riemann correlator in de Sitter including loop corrections from conformal fields
Markus B. Fröb, Albert Roura, Enric Verdaguer
The Riemann correlator with appropriately raised indices characterizes in a gauge-invariant way the quantum metric fluctuations around de Sitter spacetime including loop correction…
Mode-sum construction of the two-point functions for the Stueckelberg vector fields in the Poincaré patch of de Sitter space
Markus B. Fröb, Atsushi Higuchi
We perform canonical quantization of the Stueckelberg Lagrangian for massive vector fields in the conformally flat patch of de Sitter space in the Bunch-Davies vacuum and find thei…
Nonperturbative semiclassical stability of de Sitter spacetime for small metric deviations
Markus B. Fröb, Demetrios B. Papadopoulos, Albert Roura +1
We consider the linearized semiclassical Einstein equations for small deviations around de Sitter spacetime including the vacuum polarization effects of conformal fields. Employing…
One-loop gravitational wave spectrum in de Sitter spacetime
Markus B. Fröb, Albert Roura, Enric Verdaguer
The two-point function for tensor metric perturbations around de Sitter spacetime including one-loop corrections from massless conformally coupled scalar fields is calculated exact…
Analytical approximation of the exterior gravitational field of rotating neutron stars
C. Teichmüller, M. B. Fröb, F. Maucher
It is known that Bäcklund transformations can be used to generate stationary axisymmetric solutions of Einstein's vacuum field equations with any number of constants. We will use t…