Carsten Gundlach

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As first discovered by Choptuik, the black hole threshold in the space of initial data for general relativity shows both surprising structure and surprising simplicity. Universality, power-law scaling of the black hole mass, and scale echoing have given rise to the term "critical phenomena". They are explained by the existence of exact solutions which are(More)
M. Alcubierre, S. Brandt, B. Brügmann, C. Gundlach, J. Massó, E. Seidel, P. Walker Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Schlaatzweg 1, 14473 Potsdam, Germany (2) National Center for Supercomputing Applications, Beckman Institute, 405 N. Mathews Ave., Urbana, IL 61801 (3) Departments of Astronomy and Physics, University of(More)
I construct a spherically symmetric solution for a massless real scalar field minimally coupled to general relativity which is discretely self-similar (DSS) and regular. This solution coincides with the intermediate attractor found by Choptuik in critical gravitational collapse. The echoing period is ∆ = 3.4453 ± 0.0005. The solution is continued to the(More)
During plastic deformation of metals and alloys, dislocations arrange in ordered patterns. How and when these self-organization processes take place have remained elusive, because in situ observations have not been feasible. We present an x-ray diffraction method that provided data on the dynamics of individual, deeply embedded dislocation structures.(More)
The apparent horizon boundary condition (AHBC) appears to be one of the fundamental techniques required for evolving black hole spacetimes using numerical techniques. In this paper, we present work on an AHBC in the context of the recently formulated Bona-Massó (BM) hyperbolic system for the Einstein Evolution equations, however in doing so, we present a(More)
By fine-tuning generic Cauchy data, critical phenomena have recently been discovered in the black hole/no black hole “phase transition” of various gravitating systems. For the spherisymmetric real scalar field system, we find the “critical” spacetime separating the two phases by demanding discrete scale-invariance, analyticity, and an additional(More)
In many situations of astrophysical interest, spherical symmetry is a good approximation for modeling a star in general relativity. One possible direction in which to go beyond that approximation is to allow for arbitrary linear perturbations, in order to add gravitational radiation to the picture. This introduces new physics, as the star can now lose(More)
We observed the in situ growth of a grain during recrystallization in the bulk of a deformed sample. We used the three-dimensional x-ray diffraction microscope located at the European Synchrotron Radiation Facility in Grenoble, France. The results showed a very heterogeneous growth pattern, contradicting the classical assumption of smooth and spherical(More)