587 research outputs found
Backreacting p-wave Superconductors
We study the gravitational backreaction of the non-abelian gauge field on the
gravity dual to a 2+1 p-wave superconductor. We observe that as in the
system a second order phase transition exists between a superconducting and a
normal state. Moreover, we conclude that, below the phase transition
temperature the lowest free energy is achieved by the p-wave solution. In
order to probe the solution, we compute the holographic entanglement entropy.
For both and systems the entanglement entropy satisfies an area law.
For any given entangling surface, the p-wave superconductor has lower
entanglement entropy.Comment: Minor Typos corrected, version published in JHE
Stability of Charged Global AdS Spacetimes
We study linear and nonlinear stability of asymptotically AdS solutions
in Einstein-Maxwell-scalar theory. After summarizing the set of static
solutions we first examine thermodynamical stability in the grand canonical
ensemble and the phase transitions that occur among them. In the second part of
the paper we focus on nonlinear stability in the microcanonical ensemble by
evolving radial perturbations numerically. We find hints of an instability
corner for vanishingly small perturbations of the same kind as the ones present
in the uncharged case. Collapses are avoided, instead, if the charge and mass
of the perturbations come to close the line of solitons. Finally we examine the
soliton solutions. The linear spectrum of normal modes is not resonant and
instability turns on at extrema of the mass curve. Linear stability extends to
nonlinear stability up to some threshold for the amplitude of the perturbation.
Beyond that, the soliton is destroyed and collapses to a hairy black hole. The
relative width of this stability band scales down with the charge Q, and does
not survive the blow up limit to a planar geometry.Comment: 43 pg, 22 fig. Published version. Appendix adde
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Molyneuxâs Question in Berkeleyâs Theory of Vision
Propongo una lectura del Ensayo sobre una nueva teorĂa de la visiĂłn de Berkeley en la que las preguntas tipoMolyneux son interpretadas como experimentos mentales en lugar de argumentos. Primero, presento la estrategia argumentativa general en el NTV, y ofrezco motivos para la lectura tradicional. Segundo, atiendo a algunos roles de los experimentos mentales, y clasifico las preguntas tipo-Molyneux en el NTV como experimentos mentales constructivos conjeturales. Tercero, sostengo que (i) no hay distinciĂłn entre tesis de la Heterogeneidad DĂ©bil y Fuerte en el NTV; (ii) que la Heterogeneidad Fuerte es la base de la teorĂa de Berkeley; y (iii) que las preguntas tipo-Molyneux actĂșan como ilustraciones de la Heterogeneidad Fuerte.; I propose a reading of Berkeleyâs Essay towards a New Theory of Vision in which Molyneux-type questions are interpreted as thought experiments instead of arguments. First, I present the general argumentative strategy in the NTV, and provide grounds for the traditional eading. Second, I consider some roles of thought experiments, and classify Molyneux-type questions in the NTV as constructive conjectural thought experiments. Third, I argue that (i) there is no distinction between Weak and Strong Heterogeneity theses in the NTV; (ii) that Strong Heterogeneity is the basis of Berkeleyâs theory; and (iii) that Molyneux-type questions act as illustrations of Strong Heterogeneit
Emotions as functional kinds: A meta-theoretical approach to constructing scientific theories of emotions
In this dissertation, I address the question of how to construct scientific theories of emotions that are both conceptually sound and empirically fruitful. To do this, I offer an analysis of the main challenges scientific theories of emotions face, and I propose a meta-theoretical framework to construct scientific concepts of emotions as explications of folk emotion concepts. Part I discusses the main challenges theories of emotions in psychology and neuroscience encounter. The first states that a proper scientific theory of emotions must explain all and only the phenomena under the vernacular term âemotionâ with a common set of conceptual resources and under an overarching generic concept of emotion. The second demands that each emotion category corresponds to well-coordinated sets of neural, physiological, and behavioral patterns of responses. I argue that none of the best contemporary theories of emotions in psychology and neuroscience overcomes these challenges. As a result, a new theory of emotions is required. In Part II, I develop the meta-theoretical framework to construct a theory of emotions that overcomes the challenges above. First, I propose a pluralistic account of scientific kinds based on different patterns of projection that various disciplines may take to justify inductive inferences. These are essentialist, historical, and social patterns. Each of these patterns provides a framework to construct different types of scientific concepts. I argue that among the frameworks for scientific kinds available, the one that is best suited to explicate emotion concepts is a functional framework. Consequently, I conclude by recommending scientists pursue functionalist theories of emotions over essentialist, historical, or social theories
Anisotropic Unruh temperatures
The relative entropy between very high-energy localized excitations and the vacuum, where both states are reduced to a spatial region, gives place to a precise definition of a local temperature produced by vacuum entanglement across the boundary. This generalizes the Unruh temperature of the Rindler wedge to arbitrary regions. The local temperatures can be read off from the short distance leading have a universal geometric expression that follows by solving a particular eikonal type equation in Euclidean space. This equation generalizes to any dimension the holomorphic property that holds in two dimensions. For regions of arbitrary shapes the local temperatures at a point are direction dependent. We compute their explicit expression for the geometry of a wall or strip.Fil: Arias, RaĂșl Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; ArgentinaFil: Casini, Horacio German. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Bariloche; ArgentinaFil: Huerta, Marina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Bariloche; ArgentinaFil: Pontello, Diego Esteban. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Bariloche; Argentin
Intermediate scalings for solv, nil, and SL2 (R) black branes
In this work, we will study black brane solutions that are not translationally invariant in the spatial directions along which it extends. Instead, we require homogeneity, which still allows points along the spatial directions to be related to each other by symmetries. We find Einstein-Maxwell-anti-de Sitter black hole solutions of which the near-horizon geometry corresponds to solv (Bianchi V1-1), nil (Bianchi II), or SL2(R) (Bianchi VIII). Interestingly, we observe that at intermediate temperatures our solutions have an scaling regime where different spacetime directions scale differently. We also compute the dc conductivities for these charged solutions and study how they scale in this intermediate regime.Fil: Arias, RaĂșl Eduardo. Scuola Internazionale Superiore Di Studi Avanzati; Italia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; ArgentinaFil: Landea, Ignacio Salazar. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Bariloche; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; Argentin
Hydrodynamic modes of a holographic pâwave superfluid
In this work we analyze the hydrodynamics of a pâ wave superfluid on its strongly coupled regime by considering its holographic description. We obtain the poles of the retarded Green function through the computation of the quasi-normal modes of the dual AdS black hole background finding diffusive, pseudo-diffusive and sound modes. For the sound modes we compute the speed of sound and its attenuation as function of the temperature. For the diffusive and pseudo-diffusive modes we find that they acquire a non-zero real part at certain finite momentum.Instituto de FĂsica La Plat
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