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Related papers: Boundary contributions in the causal set action

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We derive a formula for the spacetime volume of a small causal cone. We use this formula within the context of causal set theory to construct causal set expressions for certain geometric quantities relating to a spacetime with a spacelike…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Ian Jubb

Connes' functional formula of the Riemannian distance is generalized to the Lorentzian case using the so-called Lorentzian distance, the d'Alembert operator and the causal functions of a globally hyperbolic spacetime. As a step of the…

General Relativity and Quantum Cosmology · Physics 2014-11-17 V. Moretti

We give a new short proof of the theorem due to Marquis and Sabok, which states that the orbit equivalence relation induced by the action of a finitely generated hyperbolic group on its Gromov boundary is hyperfinite. Our methods permit…

Group Theory · Mathematics 2023-06-06 Petr Naryshkin , Andrea Vaccaro

Employing a conformal map to hyperbolic space cross a circle, we compute the universal contribution to the vacuum entanglement entropy (EE) across a sphere in even-dimensional conformal field theory. Previous attempts to derive the EE in…

High Energy Physics - Theory · Physics 2016-03-23 Christopher P. Herzog , Kuo-Wei Huang , Kristan Jensen

Considering a generalization of the Gibbons-Hawking-York covariant boundary action that depends on both the extrinsic and the intrinsic geometry of the boundary, we derive boundary conditions for the cosmological background and tensor…

General Relativity and Quantum Cosmology · Physics 2023-05-26 David Brizuela , Marco de Cesare

We study expansions near the boundary of solutions to the Dirichlet problem for the constant mean curvature equation in the hyperbolic space. With a characterization of remainders of the expansion by multiple integrals, we establish optimal…

Analysis of PDEs · Mathematics 2016-08-30 Qing Han , Yue Wang

We establish the convergence to the equilibrium for various linear collisional kinetic equations (including linearized Boltzmann and Landau equations) with physical local conservation laws in bounded domains with general Maxwell boundary…

Analysis of PDEs · Mathematics 2021-02-16 Armand Bernou , Kleber Carrapatoso , Stéphane Mischler , Isabelle Tristani

We extend Pearl's definition of causal influence to the quantum domain, where two quantum systems $A$, $B$ with finite-dimensional Hilbert space are embedded in a common environment $C$ and propagated with a joint unitary $U$. For finite…

Quantum Physics · Physics 2022-12-28 Llorenç Escolà-Farràs , Daniel Braun

In this work we provide the full description of the upper levels of the classical causal ladder for spacetimes in the context of Lorenztian length spaces, thus establishing the hierarchy between them. We also show that global hyperbolicity,…

General Relativity and Quantum Cosmology · Physics 2020-10-16 L. Ake Hau , Armando J. Cabrera Pacheco , Didier A. Solis

Well-posedness of the initial (boundary) value problem is an essential property, both of meaningful physical models and of numerical applications. To prove well-posedness of wave-type equations their level of hyperbolicity is an essential…

General Relativity and Quantum Cosmology · Physics 2013-03-20 Ronny Richter , David Hilditch

We find the generalization of Einstein equations to Finsler spaces by variational means and, based on the invariance of the Finslerian Hilbert action to infinitesimal transformations, we find the analogue of the energy- momentum…

General Relativity and Quantum Cosmology · Physics 2011-11-08 Nicoleta Voicu

The cosmological constant and the Boltzmann entropy of a Newtonian Universe filled with a perfect fluid are computed, under the assumption that spatial sections are copies of 3-dimensional hyperbolic space.

General Relativity and Quantum Cosmology · Physics 2022-09-07 J. C. Castro-Palacio , P. Fernandez de Cordoba , R. Gallego Torrome , J. M. Isidro

We consider simply connected bodies or regions of finite extent in space or space-time and write conservation laws associated with the equations in Parts I-IV. We review earlier work where, for elliptic equations,the boundary value problem…

Mathematical Physics · Physics 2021-09-24 Graeme W. Milton

We prove that a globally hyperbolic spacetime with its causality relation is a bicontinuous poset whose interval topology is the manifold topology. This provides an abstract mathematical setting in which one can study causality independent…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Keye Martin , Prakash Panangaden

We consider a reaction-diffusion system where some components react and diffuse on the boundary of a region, while other components diffuse in the interior and react with those on the boundary through mass transport. We establish criteria…

Analysis of PDEs · Mathematics 2015-12-31 Vandana Sharma , Jeff Morgan

The continuum limit of a 4-dimensional, discrete d'Alembertian operator for scalar fields on causal sets is studied. The continuum limit of the mean of this operator in the Poisson point process in 4-dimensional Minkowski spacetime is shown…

General Relativity and Quantum Cosmology · Physics 2016-12-14 Alessio Belenchia , Dionigi M. T. Benincasa , Fay Dowker

We derive the generalization of Wigner's causality bounds and Bethe's integral formula for the effective range parameter to arbitrary dimension and arbitrary angular momentum. We also discuss the impact of these constraints on the…

Nuclear Theory · Physics 2015-05-18 H. -W. Hammer , Dean Lee

We study the inverse problems for the second order hyperbolic equations of general form with time-dependent coefficients assuming that the boundary data are given on a part of the boundary. The main result of this paper is the determination…

Analysis of PDEs · Mathematics 2017-07-18 Gregory Eskin

We study in details the long-time asymptotic behavior of a relativistic diffusion taking values in the unitary tangent bundle of a curved Lorentzian manifold, namely a spatially flat and fast expanding Robertson-Walker space-time. We prove…

Probability · Mathematics 2014-05-02 Jürgen Angst

We consider the projectivization of Minkowski space with the analytic continuation of the hyperbolic metric and call this an extended hyperbolic space. We can measure the volume of a domain lying across the boundary of the hyperbolic space…

Metric Geometry · Mathematics 2007-05-23 Yunhi Cho , Hyuk Kim