Low temperature properties of holographic condensates

In the current work we study various models of holographic superconductors at low temperature. Generically the zero temperature limit of those models are solitonic solution with a zero sized horizon. Here we generalized simple version of those zero temperature solutions to small but non-zero temperature T. We confine ourselves to cases where near horizon geometry is AdS^4. At a non-zero temperature a small horizon would form deep inside this AdS^4 which does not disturb the UV physics. The resulting geometry may be matched with the zero temperature solution at an intermediate length scale. We understand this matching from separation of scales by setting up a perturbative expansion in gauge potential. We have a better analytic control in abelian case and quantities may be expressed in terms of hypergeometric function. From this we calculate low temperature behavior of various quatities like entropy, charge density and specific heat etc. We also calculate various energy gaps associated with p-wave holographic superconductor to understand the underlying pairing mechanism. The result deviates significantly from the corresponding weak coupling BCS counterpart.Comment: 17 Page

Holographic phase transition from dyons in an AdS black hole background

We construct a dyon solution for a Yang-Mills-Higgs theory in a 4 dimensional Schwarzschild-anti-de Sitter black hole background with temperature T. We then apply the AdS/CFT correspondence to describe the strong coupling regime of a 2+1 quantum field theory which undergoes a phase transition exhibiting the condensation of a composite charge operator below a critical temperature $T_c$.Comment: 19 pages, 7 figures. Minor corrections, references added. Version published in JHEP

The Dreaming Variational Autoencoder for Reinforcement Learning Environments

Reinforcement learning has shown great potential in generalizing over raw sensory data using only a single neural network for value optimization. There are several challenges in the current state-of-the-art reinforcement learning algorithms that prevent them from converging towards the global optima. It is likely that the solution to these problems lies in short- and long-term planning, exploration and memory management for reinforcement learning algorithms. Games are often used to benchmark reinforcement learning algorithms as they provide a flexible, reproducible, and easy to control environment. Regardless, few games feature a state-space where results in exploration, memory, and planning are easily perceived. This paper presents The Dreaming Variational Autoencoder (DVAE), a neural network based generative modeling architecture for exploration in environments with sparse feedback. We further present Deep Maze, a novel and flexible maze engine that challenges DVAE in partial and fully-observable state-spaces, long-horizon tasks, and deterministic and stochastic problems. We show initial findings and encourage further work in reinforcement learning driven by generative exploration.Comment: Best Student Paper Award, Proceedings of the 38th SGAI International Conference on Artificial Intelligence, Cambridge, UK, 2018, Artificial Intelligence XXXV, 201

p-wave Holographic Superconductors and five-dimensional gauged Supergravity

We explore five-dimensional ${\cal N}=4$ $SU(2)\times U(1)$ and ${\cal N}=8$ SO(6) gauged supergravities as frameworks for condensed matter applications. These theories contain charged (dilatonic) black holes and 2-forms which have non-trivial quantum numbers with respect to U(1) subgroups of SO(6). A question of interest is whether they also contain black holes with two-form hair with the required asymptotic to give rise to holographic superconductivity. We first consider the ${\cal N}=4$ case, which contains a complex two-form potential $A_{\mu\nu}$ which has U(1) charge $\pm 1$. We find that a slight generalization, where the two-form potential has an arbitrary charge $q$, leads to a five-dimensional model that exhibits second-order superconducting transitions of p-wave type where the role of order parameter is played by $A_{\mu\nu}$, provided $q \gtrsim 5.6$. We identify the operator that condenses in the dual CFT, which is closely related to ${\cal N}=4$ Super Yang-Mills theory with chemical potentials. Similar phase transitions between R-charged black holes and black holes with 2-form hair are found in a generalized version of the ${\cal N}=8$ gauged supergravity Lagrangian where the two-forms have charge $q\gtrsim 1.8$.Comment: 35 pages, 14 figure

Metacarpophalangeal pattern profile analysis of a sample drawn from a North Wales population

This is tha author's PDF version of an article published in Annals of human biology© 2001. The definitive version is available at http://www.tandf.co.uk/journalsSexual dimorphism and population differences were investigated using metacarpophalangeal pattern profile (MCPP) analysis. Although it is an anthropmetric technique, MCPP analysis is more frequently used in genetic syndrome analysis and has been under-used in the study of human groups. The present analysis used a series of hand radiographics from Gwynedd, North Wales, to make comparisons, first, between the sexes within the sample and then with previously reported data from Japan. The Welsh sexes showed MCPP analyses that indicated size and shape differences but certain similarities in shape were also evident. Differences with the Japanese data were more marked. MCPP anlysis is a potentially useful anthropmetric technique but requires further statistical development

The sum of the parts is greater than the whole: Multi-scalar socio-spatial definitions of identity in Karachi's Muhajir majority areas

Notions of identity and community like space consist of varying scales of definition and interaction ranging from concepts of nationhood and nationality through to local solidarities and affiliations of religion, trade, caste etc. Space Syntax research suggests that most people belong to communities that are both spatial and transpatial in nature where inhabitants of an area are bound not only to the people and spaces they physically inhabit but are simultaneously part of a larger transpatial community independent of the immediate physical context. In the context of Karachi's Muhajir community, an ethno-political entity that has evolved through spatio-political constraints applied to an amalgam of assorted post-Partition urban minority groups, these socio-spatial variations in definition of identity can be studied across the changing scale of the city. Using space syntax methodologies, this paper examines the spatial definitions of identity, i.e. how affiliations and solidarities vary across the changing scales of the city and, how the use and positioning of communal tools of identification organize and articulate spatial clusters. This study used a range of sources to map religious and political institutions as well as on-site documentation of political propaganda and related the location of these features to space syntax models of the city and four case study settlements. The intention was to analyse the accessibility and clustering of various communal spaces, how spatial configuration defines the social role communal spaces play within the community and how they may define the spatial limits of sub-clusters and internal social hierarchies of the community. This multi-scalar analysis will show that not only does the nature of the muhajir cluster change across the various scales of the city, the nature and scale of the interface between the community and the city changes too. At the city scale communal institutions articulate broad residential clusters often synonymous with political territories, indicative of spaces of dispute, at the scale of the settlement, the configuration of communal spaces describes and dictates the manner in which these communities interact, organize and define themselves internally. Identity is therefore multi-scalar; a group may present as one ethno-political entity at the scale of the city, it may simultaneously exist as multiple ethno-religious groups at the scale of the settlement. Whilst neither definition negates the other, analysis shows that broad political definitions hide richer, more nuanced definitions of identity that persist at the scale of the settlement

A Report on the Preliminary design of Composite Cocured LCA Fin

A report on the preliminary design of composite cocured LCA fin is presented. A six spar structural configuration involving laminated carbon composite construction is employed in the design of torsion box. The design studies are carried out using a strength of materials based analysis. Three critical loading cases have been considered in the investigation. Results for various cases studied are presented and discussed

Karachi: The transformation and spatial politics of a Post-colonial migrant city

The partition of the Indian Sub-continent in 1947 resulted in the mass movement of people between India and Pakistan with a number of Urdu-speaking, Muslim communities choosing to re-settle in Karachi, Pakistan. These Muhajir or "refugee" communities have now been resident in the city for over 60 years and whilst the term traditionally means "refugee" in Urdu-their mother-tongue-in the context of Karachi today, it refers specifically to the descendants of these first wave (Partition, 1947) Urdu-speaking migrants from India. The community was initially seen as a landless, rootless people but, over time, they have become one of the key actors in the ethno-political landscape of urban Sindh, in Pakistan today. Whilst the political exploits of this community have been extensively reported and documented by anthropologists and journalist as part of Karachi's tumultuous political history, little has been written about the settlements and spatial practices of this amalgam of diverse, primarily North Indian migrant communities and how their arrival, and occupation has impacted and transformed the manner in which the city has developed. Using space syntax analysis and information drawn from master-plans, urban development reports, historical accounts, and political, religious and linguistic identity-markers associated with the Muhajir community, this study analyses how the city of Karachi has grown and developed through the last 65 years of its post-Partition history and tracks the settlement patterns of the Muhajir community into and around the city. The study shows that, whilst Karachi may be considered a Muhajir city, the community established clusters in very specific areas of the city at the time of their first settlement in the early 1950s and, whilst newer areas have been added to the city, these community-based clusters have persisted and densified over time. The manner in which the community has consolidated and marked its spaces in the city and the way their presence has impacted its growth seems to suggest that the community's identity has gone through a process of transformation and concretisation from Muhajirs as disadvantaged refugees to Muhajirs as a formidable ethnic group with considerable political clout that they exercise with regard to decisions that pertain to the growth and development of the city today

Sequences of dipole black rings and Kaluza-Klein bubbles

We construct new exact solutions to 5D Einstein-Maxwell equations describing sequences of Kaluza-Klein bubbles and dipole black rings. The solutions are generated by 2-soliton transformations from vacuum black ring - bubble sequences. The properties of the solutions are investigated. We also derive the Smarr-like relations and the mass and tension first laws in the general case for such configurations of Kaluza-Klein bubbles and dipole black rings. The novel moment is the appearance of the magnetic flux in the Smarr-like relations and the first laws.Comment: 26 pages, 1 figur