Classical integrable theories fail to thermalize. This situation can be attributed to the presence of the extensive number of integrals of motion that preclude exploration of the phase space. The...Show moreClassical integrable theories fail to thermalize. This situation can be attributed to the presence of the extensive number of integrals of motion that preclude exploration of the phase space. The further question to ask is what happens in the quantum integrable case. The answer turns to be more sophisticated than in the classical case and may, in particular, depend on a) what one means by thermalization and b) which local observables are considered. The no-go condition presented in this thesis will help to clarify these conditions when thermalization is defined in a particular way. This no-go condition will be applied to several examples of quantum integrable models.Show less
Adopting some key ideas of the AdS/CFT correspondence, such as the geometrization of the RG formalism and having an AdS background spacetime, mappings of the 1D and 2D Ising model onto a network...Show moreAdopting some key ideas of the AdS/CFT correspondence, such as the geometrization of the RG formalism and having an AdS background spacetime, mappings of the 1D and 2D Ising model onto a network model were developed. The mappings primarily serve to engineer a 2D phase transition into a higher dimensional tree network and show what holographic properties are obtained by merely invoking some conceptual ’ingredients’ from the holographic duality. The networks were studied by MC simulation of the Ising model and subsequent construction. This thesis then further reports on efforts to describe the network ensemble seeded off the Ising model independently, by a(n) (exponential) random graph model.Show less
In this thesis a detailed description of the KKLT scenario is given as well as as a comparison with later papers critiquing this model. An attempt is made to provide a some clarity in 17 years...Show moreIn this thesis a detailed description of the KKLT scenario is given as well as as a comparison with later papers critiquing this model. An attempt is made to provide a some clarity in 17 years worth of debate. It concludes with a summary of the findings and possible directions for further research.Show less
This masters thesis aims to give a coherent review of the much discussed Sachdev-Ye-Kitaev (SYK) models. The focus will be on detailed calculations leading to the most important results of...Show moreThis masters thesis aims to give a coherent review of the much discussed Sachdev-Ye-Kitaev (SYK) models. The focus will be on detailed calculations leading to the most important results of different types of SYK models. These calculations are done in a way that should be comprehensible to theoretical physics master students and starting PhD students. After doing so we will discuss some versions of SYK chains. In the end of this thesis we direct our attention to the conductivity through one such chain.Show less
An overview of Quantum Field Theory dualities is given, highlighting the tools physicists have been using to derive them and the importance of symmetries in searching for such dualities. Most...Show moreAn overview of Quantum Field Theory dualities is given, highlighting the tools physicists have been using to derive them and the importance of symmetries in searching for such dualities. Most duality derivations take place in 2+1d where one may use flux attachment to realise dualities between fermionic and bosonic theories. The phase transition method for finding dualities is then discussed in 2+1d and 3+1d, and a novel derivation of the Montonen-Olive duality is given using this method.Show less
We describe a complete strategy to numerically compute the collapse of a massless U(1) charged scalar field into a black brane final state in 4+1-dimensional anti-de Sitter space. We implement this...Show moreWe describe a complete strategy to numerically compute the collapse of a massless U(1) charged scalar field into a black brane final state in 4+1-dimensional anti-de Sitter space. We implement this strategy to investigate the formation of scalar hair, corresponding to a superconducting order parameter in a dual conformal field theory. We show that the approach to the final state takes the form of damped oscillations, with the degree of damping being strongly dependent on the temperature of the final state, as well as on the near-boundary shape of the initial distribution.Show less
The main aim of this thesis is to review the Fuzzball proposal, an alternative description for the black holes.After a brief look to basic black hole solutions of general relativity, we present the...Show moreThe main aim of this thesis is to review the Fuzzball proposal, an alternative description for the black holes.After a brief look to basic black hole solutions of general relativity, we present the two paradoxes that arise in their classical description.The Entropy Problem and the Information Paradox.Then we proceed by constructing black hole solutions in the string theory’s framework. There we compute the entropy both macroscopically and microscopically and find a remarkable agreement that save us from the Entropy Problem.In the last chapter we examine the fuzzball conjecture.According to that, the true nature of a black hole is that of a family of horizonless regular solutions,that asymptotically look like the usual black hole metric but differ from it up to the horizon region. We argue how this radical change in our description can give us a way out of the Information Paradox and save the unitarity of quantum theory.Show less
The Low energy effective Lagrangian of a supersymmetric variation of a Yang--Mills--Higgs Lagrangian, will be derived, where both Lagrangians are still N=2 supersymmetric massless Lagrangians. The...Show moreThe Low energy effective Lagrangian of a supersymmetric variation of a Yang--Mills--Higgs Lagrangian, will be derived, where both Lagrangians are still N=2 supersymmetric massless Lagrangians. The effective Lagrangian is the fixed in a couple of steps in an indirect way. First quantum field theoretic perturbation theory is used for asymptotic behaviour near some identified singularities. Then, with the use of a family of cubic curves as manifolds, and some complex analysis on holomorphic functions, the effective Lagrangian is fixed.Show less
