TY - JOUR A1 - Huber, Albert T1 - Remark on the quasilocal calculation of tidal heating: Energy transfer through the quasilocal surface JF - American Physical Society - Physical Review D N2 - In this paper, using the quasilocal formalism of Brown and York, the flow of energy through a closed surface containing a gravitating physical system is calculated in a way that augments earlier results on the subject by Booth and Creighton. To this end, by performing a variation of the total gravitational Hamiltonian (bulk plus boundary part), it is shown that associated tidal heating and deformation effects generally are larger than expected. This is because the aforementioned variation leads to previously unrecognized correction terms, including a bulk-to-boundary inflow term that does not appear in the original calculation of the time derivative of the Brown-York energy and leads to corrective extensions of Einstein’s quadrupole formula in the large sphere limit. KW - gravitation KW - cosmology KW - fields Y1 - VL - 105 IS - 2 ER - TY - JOUR A1 - Huber, Albert T1 - The gravitational field of a massless particle on the horizon of a stationary black hole JF - Classical and Quantum Gravity N2 - In this work, the field of a gravitational shockwave generated by a massless point-like particle is calculated at the event horizon of a stationary Kerr–Newman black hole. Using the geometric framework of generalized Kerr–Schild deformations in combination with the spin-coefficient formalism of Newman and Penrose, it is shown that the field equations of the theory, at the event horizon of the black hole, can be reduced to a single linear ordinary differential equation for the so-called profile function of the geometry. This differential relation is solved exactly. Based on the results obtained, a physical interpretation is given for the found shockwave spacetime, and it is clarified how these results lead back to those of previous works on the subject, which deal with the much simpler cases of gravitational shockwaves in static black hole backgrounds. KW - Gravitation Y1 - ER - TY - JOUR A1 - Huber, Albert T1 - Junction Conditions and local Spacetimes in General Relativity JF - The European Physical Journal C N2 - In the present work, a theoretical framework focussing on local geometric deformations is introduced in order to cope with the problem of how to join spacetimes with different geometries and physical properties. This framework is used to show that two Lorentzian manifolds can be matched by considering local deformations of the associated spacetime metrics. Based on the fact that metrics can be suitably matched in this way, it is shown that the underlying geometric approach allows the characterization of local spacetimes in general relativity. Furthermore, it is shown that said approach not only extends the conventional thin shell formalism, but also allows the treatment of geometric problems that cannot be treated with standard gluing techniques. KW - Relativity Y1 - ER - TY - JOUR A1 - Huber, Albert T1 - Hidden Killing fields, geometric symmetries and black hole mergers JF - Annals of Physics N2 - In the present work, using the recently introduced framework of local geometric deformations, special types of vector fields – so-called hidden Killing vector fields – are constructed, which solve the Killing equation not globally, but only locally, i.e. in local subregions of spacetime. Taking advantage of the fact that the vector fields coincide locally with Killing fields and therefore allow the consideration of integral laws that convert into exact physical conservation laws on local scales, balance laws in dynamical systems without global Killing symmetries are derived that mimic as closely as possible the conservation laws for energy and angular momentum of highly symmetric models. The utility of said balance laws is demonstrated by a concrete geometric example, namely a toy model for the binary merger of two extremal Reissner–Nordström black holes. KW - Hidden Killing KW - Vectors Phantom symmetries KW - Conservation laws Y1 - VL - 434 ER - TY - JOUR A1 - Huber, Albert T1 - Quasilocal corrections to Bondi’s mass-loss formula and dynamical horizons JF - Physical Review D KW - Bondi´s mass-loss formula KW - quasilocal KW - dynamical horizons Y1 - U6 - http://dx.doi.org/https://doi.org/10.1103/PhysRevD.108.084056 VL - Vol. 108 IS - issue 8 ER -