Stability and Thermodynamics of AdS Black Holes with Scalar Hair

Recently a class of static spherical black hole solutions with scalar hair was found in four and five dimensional gauged supergravity with modified, but AdS invariant boundary conditions. These black holes are fully specified by a single conserved charge, namely their mass, which acquires a contribution from the scalar field. Here we report on a more detailed study of some of the properties of these solutions. A thermodynamic analysis shows that in the canonical ensemble the standard Schwarzschild-AdS black hole is stable against decay into a hairy black hole. We also study the stability of the hairy black holes and find there always exists an unstable radial fluctuation, in both four and five dimensions. We argue, however, that Schwarzschild-AdS is probably not the endstate of evolution under this instability.Comment: 18 pages, 4 figure

Violation of Energy Bounds in Designer Gravity

We continue our study of the stability of designer gravity theories, where one considers anti-de Sitter gravity coupled to certain tachyonic scalars with boundary conditions defined by a smooth function W. It has recently been argued there is a lower bound on the conserved energy in terms of the global minimum of W, if the scalar potential arises from a superpotential P and the scalar reaches an extremum of P at infinity. We show, however, there are superpotentials for which these bounds do not hold.Comment: 16 pages, 4 figures, v2: discussion of vacuum decay included, typos corrected, reference adde

Particle Production near an AdS Crunch

We numerically study the dual field theory evolution of five-dimensional asymptotically anti-de Sitter solutions of supergravity that develop cosmological singularities. The dual theory is an unstable deformation of the N = 4 gauge theory on R $\times$ S3, and the big crunch singularity in the bulk occurs when a boundary scalar field runs to infinity. Consistent quantum evolution requires one imposes boundary conditions at infinity. Modeling these by a steep regularization of the scalar potential, we find that when an initially nearly homogeneous wavepacket rolls down the potential, most of the potential energy of the initial configuration is converted into gradient energy during the first oscillation of the field. This indicates there is no transition from a big crunch to a big bang in the bulk for dual boundary conditions of this kind.Comment: 20 pages, 6 figure

Origin of Spin Ice Behavior in Ising Pyrochlore Magnets with Long Range Dipole Interactions: an Insight from Mean-Field Theory

Recent experiments suggest that the Ising pyrochlore magnets ${\rm Ho_{2}Ti_{2}O_{7}}$ and ${\rm Dy_{2}Ti_{2}O_{7}}$ display qualitative properties of the ferromagnetic nearest neighbor spin ice model proposed by Harris {\it et al.}, Phys. Rev. Lett. {\bf 79}, 2554 (1997). The manifestation of spin ice behavior in these systems {\it despite} the energetic constraints introduced by the strength and the long range nature of dipole-dipole interactions, remains difficult to understand. We report here results from a mean field analysis that shed some light on the origin of spin ice behavior in (111) Ising pyrochlores. Specifically, we find that there exist a large frustrating effect of the dipolar interactions beyond the nearest neighbor, and that the degeneracy established by effective ferromagnetic nearest neighbor interactions is only very weakly lifted by the long range interactions. Such behavior only appears beyond a cut-off distance corresponding to $O(10^2)$ nearest neighbor. Our mean field analysis shows that truncation of dipolar interactions leads to spurious ordering phenomena that change with the truncation cut-off distance.Comment: 7 Color POSTSCRIPT figures included. To appear in Canadian Journal of Physics for the Proceedings of the {\it Highly Frustrated Magnetism 2000 Conference}, Waterloo, Ontario, Canada, June 11-15, 2000 Contact: [email protected]

Multinationals are Multicultural Units: Some Indications from a Cross-Cultural Study

This paper makes a case for the value of looking at culture and multinationals from a management and organizational perspective because it is one which could direct greater attention towards culture as a significant factor in future investigation on multinational corporations. We attempt to illustrate that multinationals are fundamentally multicultural units in more ways than one. This paper is based on selected materials from a qualitative study of culture and learning in organizations and management. The study investigated four selected Dutch firms in Thailand using evidences collected through observations and open-ended interviews. All evidences were analysed under grounded theory procedure. Parts of the evidences and theorization from the study are presented in this paper, which begins with two cultural riddles from one of the cases as a backdrop for subsequent discussions. Following the riddles is an abridge version of the key finding of the study-a grounded theory of cross-cultural intelligence. Then the two riddles are revisited, this time to illustrate how the proposed theory could illuminate an understanding of their covert meanings vis-à-vis culture and learning in multinationals. Last, we reinstate how our study and its theoretical and empirical findings can elucidate the central thesis that multinationals are essentially multicultural units.case study, culture, corporate culture, cultural intelligence, multinationals, Netherlands, Thailand

Portrait of an Odd-Eyed Cat: Cultural Crossing as a Trademark for a Dutch-Thai Strategic Alliance

This chapter attempts a step forward in seeking a richer understanding of the dynamics of strategic alliances, specifically when viewed from a cross-cultural perspective. We report selected materials from a study designed to build a theory of culture and learning in organizations based on observations of and open-ended interviews with Dutch and Thai employees working for four selected Dutch firms in Thailand. Here we present one of those cases, a Dutch-Thai joint venture that thrived by weaving together the many intricate cultural webs to achieve a unique pattern of partnership which, metaphorically speaking, became its indispensible trademark. The case illustrates how the three levels of culture – national, organizational, and professional cultures – could all interlace in a real world setting and serve as an instrumental force of success amidst tension in one particular cross-border strategic alliance. First, we adopt a thick descriptive style of case narration to present the case of a Dutch- Thai joint venture, Chuchawal-De Weger Internationaal (CDW), painting a portrait of its origin, evolution and characteristics. Next, we turn to elaborate on the particular issue of cultural crossing, its exact theorized properties, dimensions and implications. Finally, we relate the case of CDW to the proposed theory and conclude with a reflection on how this case and our interpretation of it illuminate the complex role culture can play in the dynamics of strategic alliances.cross-cultural management, culture, qualitative case study, strategic alliance, thick-description

Populating the Landscape: A Top Down Approach

We put forward a framework for cosmology that combines the string landscape with no boundary initial conditions. In this framework, amplitudes for alternative histories for the universe are calculated with final boundary conditions only. This leads to a top down approach to cosmology, in which the histories of the universe depend on the precise question asked. We study the observational consequences of no boundary initial conditions on the landscape, and outline a scheme to test the theory. This is illustrated in a simple model landscape that admits several alternative inflationary histories for the universe. Only a few of the possible vacua in the landscape will be populated. We also discuss in what respect the top down approach differs from other approaches to cosmology in the string landscape, like eternal inflation.Comment: 22 pages, 1 figur

Phase transitions near black hole horizons

The Reissner-Nordstrom black hole in four dimensions can be made unstable without violating the dominant energy condition by introducing a real massive scalar with non-renormalizable interactions with the gauge field. New stable black hole solutions then exist with greater entropy for fixed mass and charge than the Reissner-Nordstrom solution. In these new solutions, the scalar condenses to a non-zero value near the horizon. Various generalizations of these hairy black holes are discussed, and an attempt is made to characterize when black hole hair can occur.Comment: 30 pages, 6 figures. v2: minor corrections, references adde