Extending the isolated horizon phase space to string-inspired gravity models

An isolated horizon (IH) is a null hypersurface at which the geometry is held fixed. This generalizes the notion of an event horizon so that the black hole is an object that is in local equilibrium with its (possibly) dynamic environment. The first law of IH mechanics that arises from the framework relates quantities that are all defined at the horizon. IHs have been extensively studied in Einstein gravity with various matter couplings and rotation, and in asymptotically flat and asymptotically anti-de Sitter (ADS) spacetimes in all dimensions $D\geq3$. Motivated by the nonuniqueness of black holes in higher dimensions and by the black-hole/string correspondence principle, we devote this thesis to the extension of the framework to include IHs in string-inspired gravity models, specifically to Einstein-Maxwell-Chern-Simons (EMCS) theory and to Einstein-Gauss-Bonnet (EGB) theory in higher dimensions. The focus is on determining the generic features of black holes that are solutions to the field equations of the theories under consideration. We obtain various results for non-extremal, extremal and supersymmetric IHs in EM-CS theory, and for non-rotating IHs in EGB theory. (An extended abstract is given in the PDF file.)Comment: Ph.D dissertation; Memorial University of Newfoundland; 63 pages; 1 figure; v2: typos correcte

First-order action and Euclidean quantum gravity

We show that the on-shell path integral for asymptotically flat Euclidean spacetimes can be given in the first-order formulation of general relativity, without assuming the boundary to be isometrically embedded in Euclidean space and without adding infinite counter-terms. For illustrative examples of our approach, we evaluate the first-order action for the four-dimensional Euclidean Schwarzschild and NUT-charged spacetimes to derive the corresponding on-shell partition functions, and show that the correct thermodynamic quantities for the solutions are reproduced.Comment: 8 pages; v2: references added; minor corrections; v3: typos corrected in eqns (20) and (21); v4: substantially revised; addition of NUT-charged spacetimes; to appear in Classical and Quantum Gravit

Induced current and redefinition of electric and magnetic fields from non-compact Kaluza-Klein theory: An experimental signature of the fifth dimension

The field equations for gravitation and electromagnetism with sources in four dimensions can be interpreted as arising from the vacuum Einstein equations in five dimensions. Gauge invariance of the electromagnetic potentials leads to a ``generalized'' electromagnetic field tensor. We use the action principle to derive the equations of motion for free electromagnetic fields in flat spacetime, and isolate an effective electromagnetic current with a source that is purely higher-dimensional in origin. This current provides, at least in principle, a means of detecting extra dimensions experimentally.Comment: 6 pages; to appear in Physics Letters

An empirical assessment of alternative exchange rate regimes in medium term in Albania

This paper examines the alternative exchange rate regimes and their feasibility to be applied in Albania in medium term. In all empirical work done until now is been found a very low relationship between money and inflation in Albania before and after using the indirect instruments of monetary control. As a result, the motivation for finding other strategies for monetary policy and exchange rate policy is strong and has opened the debate of practitioners in this field. We argue that moving from freely floating exchange rate regime and informal IT strategy in formal IT strategy would be a more preferable strategy that will deal better with the fragile sustainability of current account deficit in Albania but not without problems to be applied. --

TFP AND ENDOGENOUS GROWTH IN SOUTH EAST EUROPEAN COUNTRIES WITH SPECIAL FOCUS ON ALBANIA

The main objective of this paper is to determine the forces that have driven the economic growth in Albania relative to Southeast and Central European countries from the beginning of transition period year 1993 until 2008, before the global crises was spread in developing countries. We are based in Growth –Accounting approach in order to specify the role of total factor productivity (TPF) as growth enhancing factor in different phases of their economic development and an econometric analyze of major growth factors based on endogenous growth theory. The main findings of this paper are: (1) TFP and capital accumulation has been playing an important role for all countries under survey, the impact of labor as growth enhancing factor has been limited (2) macroeconomic stability,trade openness, and investment in infrastructure matters to growth. Therefore we support the idea that Albania government should give priority of scare government resources towards these sectors.Productivity, economic growth, panel data analyze

Astrophysical Implications of Higher-Dimensional Gravity

We review the implications of modern higher-dimensional theories of gravity for astrophysics and cosmology. In particular, we discuss the latest developments of space-time-matter theory in connection with dark matter, particle dynamics and the cosmological constant, as well as related aspects of quantum theory. There are also more immediate tests of extra dimensions, notably involving perturbations of the cosmic 3K microwave background and the precession of a supercooled gyroscope in Earth orbit. We also outline some general features of embeddings, and include pictures of the big bang as viewed from a higher dimension.Comment: 23 pages, 2 figures; to appear in Space Science Reviews; v3: typos corrected and minor changes to text, expanded derivation of fundamental mode adde

Modeling the Behavior of Inflation Rate in Albania Using Time Series

In this paper, time series theory is used to modelling monthly inflation data in Albania during the period from January 2000 to December 2016. The autoregressive conditional heteroscedastic (ARCH) and their extensions, generalized autoregressive conditional heteroscedasticity (GARCH)) models are used to better fit the data. The study reveals that the inflation series is stationary, non-normality and has serial correlation.   Based on minimum AIC and SIC values the best model turn to be GARCH (1, 1) model with mean equation ARMA (2, 1)x(2, 0)12. Based on the selected model one year of inflation is forecasted (from January 2016 to December 2016)