Real-Time Dynamics of Plasma Balls from Holography

Plasma balls are droplets of deconfined plasma surrounded by a confining vacuum. We present the first holographic simulation of their real-time evolution via the dynamics of localized, finite-energy black holes in the five-dimensional anti–de Sitter (AdS) soliton background. The dual gauge theory is four-dimensional N = 4 super Yang-Mills theory compactified on a circle with supersymmetry-breaking boundary conditions. We consider horizonless initial data sourced by a massless scalar field. Prompt scalar field collapse produces an excited black hole at the bottom of the geometry together with gravitational and scalar radiation. The radiation disperses to infinity in the noncompact directions and corresponds to particle production in the dual gauge theory. The black hole evolves toward the dual of an equilibrium plasma ball on a time scale longer than naively expected. This feature is a direct consequence of confinement and is caused by long-lived, periodic disturbances bouncing between the bottom of the AdS soliton and the AdS boundary

Nonspherically Symmetric Collapse in Asymptotically AdS Spacetimes

We numerically simulate gravitational collapse in asymptotically anti-de Sitter spacetimes away from spherical symmetry. Starting from initial data sourced by a massless real scalar field, we solve the Einstein equations with a negative cosmological constant in five spacetime dimensions and obtain a family of non-spherically symmetric solutions, including those that form two distinct black holes on the axis. We find that these configurations collapse faster than spherically symmetric ones of the same mass and radial compactness. Similarly, they require less mass to collapse within a fixed time

String-theory-based predictions for nonhydrodynamic collective modes in strongly interacting Fermi gases

Very different strongly interacting quantum systems such as Fermi gases, quark-gluon plasmas formed in high-energy ion collisions, and black holes studied theoretically in string theory are known to exhibit quantitatively similar damping of hydrodynamic modes. It is not known if such similarities extend beyond the hydrodynamic limit. Do nonhydrodynamic collective modes in Fermi gases with strong interactions also match those from string theory calculations? In order to answer this question, we use calculations based on string theory to make predictions for modes outside the hydrodynamic regime in trapped Fermi gases. These predictions are amenable to direct testing with current state-of-the-art cold atom experiments.United States. Department of Energy (Grant DE-SC0008132)United States. Department of Energy (Contract DESC0011090

Cauchy evolution of asymptotically global AdS spacetimes with no symmetries

We present the first proof-of-principle Cauchy evolutions of asymptotically global anti–de Sitter (AdS) spacetimes with no imposed symmetries, employing a numerical scheme based on the generalized harmonic form of the Einstein equations. In this scheme, the main difficulty in removing all symmetry assumptions can be phrased in terms of finding a set of generalized harmonic source functions that are consistent with AdS boundary conditions. In four spacetime dimensions, we detail an explicit set of source functions that achieves evolution in full generality. A similar prescription should also lead to stable evolution in higher spacetime dimensions, in various couplings with matter fields, and on the Poincaré patch. We apply this scheme to obtain the first long-time stable 3 + 1 simulations of four-dimensional spacetimes with a negative cosmological constant, using initial data sourced by a massless scalar field. We present preliminary results of gravitational collapse with no symmetry assumptions, and the subsequent quasinormal mode ringdown to a static black hole in the bulk, which corresponds to evolution toward a homogeneous state on the boundary

Holographic heavy-ion collisions: Analytic solutions with longitudinal flow, elliptic flow and vorticity

We consider phenomenological consequences arising from simple analytic solutions for holographic heavy-ion collisions. For these solutions, early-time longitudinal flow is initially negative (inward), sizable direct, elliptic, and quadrangular flow is generated, and the average vorticity of the system is tunable by a single parameter. Despite large vorticity and angular momentum, we show that the system does not complete a single rotation

Simulation of Asymptotically AdS5 Spacetimes with a Generalized Harmonic Evolution Scheme

Motivated by the gauge/gravity duality, we introduce a numerical scheme based on generalized harmonic evolution to solve the Einstein field equations on asymptotically anti-de Sitter (AdS) spacetimes. We work in global AdS5, which can be described by the (t,r,\chi,\theta,\phi) spherical coordinates adapted to the R{\times}S3 boundary. We focus on solutions that preserve an SO(3) symmetry that acts to rotate the 2-spheres parametrized by \theta,\phi. In the boundary conformal field theory (CFT), the way in which this symmetry manifests itself hinges on the way we choose to embed Minkowski space in R{\times}S3. We present results from an ongoing study of prompt black hole formation via scalar field collapse, and explore the subsequent quasi-normal ringdown. Beginning with initial data characterized by highly distorted apparent horizon geometries, the metrics quickly evolve, via quasi-normal ringdown, to equilibrium static black hole solutions at late times. The lowest angular number quasi-normal modes are consistent with the linear modes previously found in perturbative studies, whereas the higher angular modes are a combination of linear modes and of harmonics arising from non-linear mode-coupling. We extract the stress energy tensor of the dual CFT on the boundary, and find that despite being highly inhomogeneous initially, it nevertheless evolves from the outset in a manner that is consistent with a thermalized N=4 SYM fluid. As a first step towards closer contact with relativistic heavy ion collision physics, we map this solution to a Minkowski piece of the R{\times}S3 boundary, and obtain a corresponding fluid flow in Minkowski space

Dryland Agriculture: Dynamics, Challenges and Priorities

The developments in the dryland region reflect the pervasiveness of poverty, which is demonstrated by the growing constraints of water, land degradation, continuing concerns about malnutrition, migration due to frequent droughts, lack of infrastructure, poor dissemination of improved technologies, and effects of government policies and further economic liberalization on the competitiveness of dryland crops. This research bulletin reviews past trends, summarizes the major constraints to income growth, food security, poverty alleviation, and environmental sustainability, and identifies future strategies and priorities. The discussion uses the semi-arid tropics as a focal point where poverty, food insecurity, child malnutrition and gender inequalities are widespread. A synthesis of evidence and lessons learned from ICRISAT Village Level Studies (VLS), conducted since 1975, is presented to provide empirical evidence on the vulnerability of the poor to various risks and shocks, as well as their capacity to access physical, financial and social resources and networks in the risky environments of the drylands. An analysis of available evidences provided a basis for identifying major policy issues that need to be addressed. Priority development interventions are identified to accelerate the pace of development of dryland agriculture: a) water as a catalyst for development; b) reorientation of public policies and better targeting of development interventions to dryland farmers, especially since they relate to key factors constraining agricultural productivity, and hence poverty reduction; c) diversification with a higher focus on crop-livestock development; d) innovative, cost effective and community based management of wastelands and common property resources; e) marketing, commercial orientation and competitiveness of dryland agriculture; and f)institutional innovations, building partnerships, linkages and capacity. The development of dryland agriculture requires synergy among technologies, marketing systems, input supplies, credit, policies and institutions. A broadbased sustainable growth and development in the drylands of Asia and sub-Saharan Africa is viewed as a key strategy for addressing rural poverty in the Asian and sub-Saharan region

Dryland Agriculture: Dynamics, Challenges and Priorities

The developments in the dryland region reflect the pervasiveness of poverty, which is demonstrated by the growing constraints of water, land degradation, continuing concerns about malnutrition, migration due to frequent droughts, lack of infrastructure, poor dissemination of improved technologies, and effects of government policies and further economic liberalization on the competitiveness of dryland crops. This research bulletin reviews past trends, summarizes the major constraints to income growth, food security, poverty alleviation, and environmental sustainability, and identifies future strategies and priorities. The discussion uses the semi-arid tropics as a focal point where poverty, food insecurity, child malnutrition and gender inequalities are widespread. A synthesis of evidence and lessons learned from ICRISAT Village Level Studies (VLS), conducted since 1975, is presented to provide empirical evidence on the vulnerability of the poor to various risks and shocks, as well as their capacity to access physical, financial and social resources and networks in the risky environments of the drylands. An analysis of available evidences provided a basis for identifying major policy issues that need to be addressed. Priority development interventions are identified to accelerate the pace of development of dryland agriculture: a) water as a catalyst for development; b) reorientation of public policies and better targeting of development interventions to dryland farmers, especially since they relate to key factors constraining agricultural productivity, and hence poverty reduction; c) diversification with a higher focus on crop-livestock development; d) innovative, cost effective and community based management of wastelands and common property resources; e) marketing, commercial orientation and competitiveness of dryland agriculture; and f)institutional innovations, building partnerships, linkages and capacity. The development of dryland agriculture requires synergy among technologies, marketing systems, input supplies, credit, policies and institutions. A broadbased sustainable growth and development in the drylands of Asia and sub-Saharan Africa is viewed as a key strategy for addressing rural poverty in the Asian and sub-Saharan region

Seasonal Migration and Moving Out of Poverty in Rural India: Insights from Statistical Analysis

Rural households in many countries have used temporary or seasonal migration as a strategy to cope with natural shocks such as drought, means of employment and income generation during lean season, and to move out of poverty. This paper studies the linkages between migration, employment in economic activities, asset accumulation, and poverty reduction among rural households in a droughtprone village of India over the last four decades. The Dokur Village of Mahbubnagar District in Telangana State of India experienced persistent drought over a decade. To cope with this situation, many households of the village temporarily migrated to the nearby and faraway cities. ICRISAT had conducted household surveys in Dokur under the Village Level Studies (VLS) and Village Dynamics Studies (VDS) program since 1975. The present study has used the VLS-VDS dataset (1975–2012) and reorganized sample households into 46 dynasty households. Based on their participation in migration, sample households were grouped into two categories: migrant and non-migrant households. Household income was computed by sources for all households for all the study years. Contribution of migratory income and remittances to the total household income was quantified. To identify the factors responsible for migration decision, probit analysis was carried out. For each year, sample households were grouped into poor and non-poor category using both lower (USD 1.25 ppp per day per person) and upper (USD 2.00 ppp per day per person) poverty line. The study revealed that seasonal out-migration helped many households to come out of poverty even though they had experienced a decade of drought. In-depth analysis of asset accumulation behaviour of the households over time revealed important insights regarding their coping mechanism and the process of moving out of poverty

Value Chain Management in Production and Marketing of Groundnut in Raichur District of Karnataka

The study has investigated the value chain management in production and marketing of groundnut in the Raichur district of Karnataka during kharif 2008. In groundnut, TMV-2 is the ruling variety occupying 85 per cent of the area in the district, but it is prone to pests and cut worm leaf minor; disease such as groundnut bud necrosis and leaf spot cause damage to the extent of 25 per cent of the yield. This has led to a decline in area under groundnut in the district, especially during kharif in comparison with rabi/summer season. Therefore, it is necessary to replace TMV-2 with high-yielding varieties incorporating the traits preferred along the value chain, i.e., production, consumption and marketing of groundnut. The existing seed supply system is meeting the seed requirement only to the extent of 7 per cent. Therefore, there is a need to strengthen the existing seed supply system for speedy seed multiplication and distribution of seeds to the farming communit