scholarly journals STRING THEORY EFFECTS ON FIVE-DIMENSIONAL BLACK HOLE PHYSICS

2008 ◽  
Vol 23 (05) ◽  
pp. 613-691 ◽  
Author(s):  
ALEJANDRA CASTRO ◽  
JOSHUA L. DAVIS ◽  
PER KRAUS ◽  
FINN LARSEN
Keyword(s):  
Black Holes ◽  
Black Hole Physics ◽  
Conformal Supergravity ◽  
Anomaly Cancellation ◽  
String Corrections ◽  
Dimensional Black Hole ◽  
Recent Developments ◽  
The One ◽  
Shell Formulation ◽  
M Theory

We review recent developments in understanding quantum/string corrections to BPS black holes and strings in five-dimensional supergravity. These objects are solutions to the effective action obtained from M-theory compactified on a Calabi–Yau threefold, including the one-loop corrections determined by anomaly cancellation and supersymmetry. We introduce the off-shell formulation of this theory obtained through the conformal supergravity method and review the methods for investigating supersymmetric solutions. This leads to quantum/string corrected attractor geometries, as well as asymptotically flat black strings and spinning black holes. With these solutions in hand, we compare our results with analogous studies in four-dimensional string-corrected supergravity, emphasizing the distinctions between the four- and five-dimensional theories.

scholarly journals Higher-derivative supergravity, AdS4 holography, and black holes

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Nikolay Bobev ◽  
Anthony M. Charles ◽  
Kiril Hristov ◽  
Valentin Reys
Keyword(s):  
Black Holes ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Conformal Supergravity ◽  
Supergravity Theory ◽  
Higher Derivative ◽  
All Solutions ◽  
M Theory ◽  
Supergravity Action

Abstract We use conformal supergravity techniques to study four-derivative corrections in four-dimensional gauged supergravity. We show that the four-derivative Lagrangian for the propagating degrees of freedom of the $$ \mathcal{N} $$ N = 2 gravity multiplet is determined by two real dimensionless constants. We demonstrate that all solutions of the two-derivative equations of motion in the supergravity theory also solve the four-derivative equations of motion. These results are then applied to explicitly calculate the regularized on-shell action for any asymptotically locally AdS4 solution of the two-derivative equations of motion. The four-derivative terms in the supergravity Lagrangian modify the entropy and other thermodynamic observables for the black hole solutions of the theory. We calculate these corrections explicitly and demonstrate that the quantum statistical relation holds for general stationary black holes in the presence of the four-derivative corrections. Employing an embedding of this supergravity model in M-theory we show how to use supersymmetric localization results in the holographically dual three-dimensional SCFT to determine the unknown coefficients in the four-derivative supergravity action. This in turn leads to new detailed results for the first subleading $$ {N}^{\frac{1}{2}} $$ N 1 2 correction to the large N partition function of a class of three-dimensional SCFTs on compact Euclidean manifolds. In addition, we calculate explicitly the first subleading correction to the Bekenstein-Hawking entropy of asymptotically AdS4 black holes in M-theory. We also discuss how to add matter multiplets to the supergravity theory in the presence of four-derivative terms and to generalize some of these results to six- and higher-derivative supergravity.

scholarly journals The near-horizon geometry of supersymmetric rotating AdS4 black holes in M-theory

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Christopher Couzens ◽  
Eric Marcus ◽  
Koen Stemerdink ◽  
Damian van de Heisteeg
Keyword(s):  
Black Holes ◽  
Equations Of Motion ◽  
Sufficient Conditions ◽  
Internal Space ◽  
Rotating Black Holes ◽  
Newman Black Hole ◽  
The One ◽  
Necessary And Sufficient ◽  
Horizon Geometry ◽  
M Theory

Abstract We classify the necessary and sufficient conditions to obtain the near-horizon geometry of extremal supersymmetric rotating black holes embedded in 11d supergravity which are associated to rotating M2-branes. Such rotating black holes admit an AdS2 near-horizon geometry which is fibered by the transverse spacetime directions. In this paper we allow for the most general fibration over AdS2 with a flux configuration permitting rotating M2-branes. Using G-structure techniques we rewrite the conditions for supersymmetry in terms of differential equations on an eight-dimensional balanced space. The 9d compact internal space is a U(1)-fibration over this 8d base. The geometry is constrained by a master equation reminiscent of the one found in the non-rotating case. We give a Lagrangian from which the equations of motion may be derived, and show how the asymptotically AdS4 electrically charged Kerr-Newman black hole in 4d $$ \mathcal{N} $$ N = 2 supergravity is embedded in the classification. In addition, we present the conditions for the near-horizon geometry of rotating black strings in Type IIB by using dualities with the 11d setup.

Biosecurity: tools, behaviours and concepts

2020 ◽  
Vol 4 (5) ◽  
pp. 449-452
Author(s):  
Alan MacLeod ◽  
Nicola Spence
Keyword(s):  
Plant Protection ◽  
Human Life ◽  
Animal Health ◽  
Early Warning Systems ◽  
Policy Makers ◽  
Recent Developments ◽  
Surveillance Programs ◽  
Harmful Organisms ◽  
The One ◽  
Biosecurity Practices

COVID 19 has raised the profile of biosecurity. However, biosecurity is not only about protecting human life. This issue brings together mini-reviews examining recent developments and thinking around some of the tools, behaviours and concepts around biosecurity. They illustrate the multi-disciplinary nature of the subject, demonstrating the interface between research and policy. Biosecurity practices aim to prevent the spread of harmful organisms; recognising that 2020 is the International Year of Plant Health, several focus on plant biosecurity although invasive species and animal health concerns are also captured. The reviews show progress in developing early warning systems and that plant protection organisations are increasingly using tools that compare multiple pest threats to prioritise responses. The bespoke modelling of threats can inform risk management responses and synergies between meteorology and biosecurity provide opportunities for increased collaboration. There is scope to develop more generic models, increasing their accessibility to policy makers. Recent research can improve pest surveillance programs accounting for real-world constraints. Social science examining individual farmer behaviours has informed biosecurity policy; taking a broader socio-cultural approach to better understand farming networks has the potential to change behaviours in a new way. When encouraging public recreationists to adopt positive biosecurity behaviours communications must align with their values. Bringing together the human, animal, plant and environmental health sectors to address biosecurity risks in a common and systematic manner within the One Biosecurity concept can be achieved through multi-disciplinary working involving the life, physical and social sciences with the support of legislative bodies and the public.

scholarly journals One-loop string corrections to AdS amplitudes from CFT

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
J.M. Drummond ◽  
H. Paul
Keyword(s):  
Stress Tensor ◽  
Analytic Structure ◽  
Position Space ◽  
Yang Mills ◽  
String Corrections ◽  
The One ◽  
Loop Amplitudes

Abstract We consider α′ corrections to the one-loop four-point correlator of the stress- tensor multiplets in $$ \mathcal{N} $$ N = 4 super Yang-Mills at order 1/N4. Holographically, this is dual to string corrections of the one-loop supergravity amplitude on AdS5 × S5. While this correlator has been considered in Mellin space before, we derive the corresponding position space results, gaining new insights into the analytic structure of AdS loop amplitudes. Most notably, the presence of a transcendental weight three function involving new singularities is required, which has not appeared in the context of AdS amplitudes before. We thereby confirm the structure of string corrected one-loop Mellin amplitudes, and also provide new explicit results at orders in α′ not considered before.

scholarly journals Islands in linear dilaton black holes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Georgios K. Karananas ◽  
Alex Kehagias ◽  
John Taskas
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Entanglement Entropy ◽  
Von Neumann Entropy ◽  
Two Dimensional ◽  
Extremal Case ◽  
Von Neumann ◽  
Dimensional Black Hole ◽  
Linear Dilaton ◽  
Linear Dilaton Black Hole

Abstract We derive a novel four-dimensional black hole with planar horizon that asymptotes to the linear dilaton background. The usual growth of its entanglement entropy before Page’s time is established. After that, emergent islands modify to a large extent the entropy, which becomes finite and is saturated by its Bekenstein-Hawking value in accordance with the finiteness of the von Neumann entropy of eternal black holes. We demonstrate that viewed from the string frame, our solution is the two-dimensional Witten black hole with two additional free bosons. We generalize our findings by considering a general class of linear dilaton black hole solutions at a generic point along the σ-model renormalization group (RG) equations. For those, we observe that the entanglement entropy is “running” i.e. it is changing along the RG flow with respect to the two-dimensional worldsheet length scale. At any fixed moment before Page’s time the aforementioned entropy increases towards the infrared (IR) domain, whereas the presence of islands leads the running entropy to decrease towards the IR at later times. Finally, we present a four-dimensional charged black hole that asymptotes to the linear dilaton background as well. We compute the associated entanglement entropy for the extremal case and we find that an island is needed in order for it to follow the Page curve.

scholarly journals Progenitors and Hydrodynamics of Type II and lb Supernovae

1996 ◽  
Vol 145 ◽  
pp. 137-147
Author(s):  
S. E. Woosley ◽  
T. A. Weaver ◽  
R. G. Eastman
Keyword(s):  
Black Holes ◽  
Light Curve ◽  
Mass Loss ◽  
Massive Stars ◽  
The Other ◽  
Shock Interaction ◽  
Type Ii ◽  
Residual Hydrogen ◽  
Ordinary Type ◽  
The One

We review critical physics affecting the observational characteristics of those supernovae that occur in massive stars. Particular emphasis is given to 1) how mass loss, either to a binary companion or by a radiatively driven wind, affects the type and light curve of the supernova, and 2) the interaction of the outgoing supernova shock with regions of increasing pr3 in the stellar mantle. One conclusion is that Type II-L supernovae may occur in mass exchanging binaries very similar to the one that produced SN 1993J, but with slightly larger initial separations and residual hydrogen envelopes (∼1 Mʘ and radius ∼ several AU). The shock interaction, on the other hand, has important implications for the formation of black holes in explosions that are, near peak light, observationally indistinguishable from ordinary Type II-p and lb supernovae.

scholarly journals A Business Model Framework to Characterize Digital Multisided Platforms

2020 ◽  
Vol 6 (1) ◽  
pp. 10 ◽  
Author(s):  
Marco Ardolino ◽  
Nicola Saccani ◽  
Federico Adrodegari ◽  
Marco Perona
Keyword(s):  
Information And Communication Technologies ◽  
Assessment Tool ◽  
Empirical Studies ◽  
Communication Technologies ◽  
Model Framework ◽  
Recent Developments ◽  
Information And Communication ◽  
Multiple Case ◽  
The One

Businesses grounded upon multisided platforms (MSPs) are found in a growing number of industries, thanks to the recent developments in Internet and digital technologies. Digital MSPs enable multiple interactions among users of different sides through information and communication technologies. The understanding of the characteristics and constituents of MSPs is fragmented along different literature streams. Moreover, very few empirical studies have been carried out to date. In order to fill this gap, this paper presents a three-level framework that describes a digital MSP. The proposed framework is based on literature analysis and multiple case study. On the one hand, the framework can be used to describe MSP as it provides an operationalization of the concept through the identification of specific dimensions, variables and items; on the other hand, it can be used as an assessment tool by practitioners, as exemplified by the three empirical applications presented in this paper.

scholarly journals Theology at Thresholds: Learning from a Practice ‘In Transition’

2017 ◽  
Vol 4 (1) ◽  
pp. 45-62 ◽  
Author(s):  
Rachel Muers ◽  
Rhiannon Grant
Keyword(s):  
Decision Making ◽  
The Other ◽  
Small Scale ◽  
Theological Ethics ◽  
Reciprocal Influence ◽  
Core Practices ◽  
Recent Developments ◽  
Collective Process ◽  
The One ◽  
Over Time

Recent developments in contemporary theology and theological ethics have directed academic attention to the interrelationships of theological claims, on the one hand, and core community-forming practices, on the other. This article considers the value for theology of attending to practice at the boundaries, the margins, or, as we prefer to express it, the threshold of a community’s institutional or liturgical life. We argue that marginal or threshold practices can offer insights into processes of theological change – and into the mediation between, and reciprocal influence of, ‘church’ and ‘world’. Our discussion focuses on an example from contemporary British Quakerism. ‘Threshing meetings’ are occasions at which an issue can be ‘threshed out’ as part of a collective process of decision-making. Drawing on a 2015 small-scale study (using a survey and focus group) of British Quaker attitudes to and experiences of threshing meetings, set in the wider context of Quaker tradition, we interpret these meetings as a space for working through – in context and over time – tensions within Quaker theology, practice and self-understandings, particularly those that emerge within, and in relation to, core practices of Quaker decision-making.

FEMINISM IN EUROPE: FACING NEW CHALLENGES

2020 ◽  
Vol 3 (1) ◽  
pp. 38-46
Author(s):  
DARIA POTAPOVA ◽  
◽  
SERGEY SHPAGIN
Keyword(s):  
European Society ◽  
Early Period ◽  
Political Movements ◽  
Left Wing ◽  
Muslim Countries ◽  
Women's Equality ◽  
State Budgets ◽  
Recent Developments ◽  
Migration Crisis ◽  
The One

The article is devoted to topical issues of the development of the ideology of feminism in modern conditions. The purpose of the work is to identify the factors of the dynamics of the ideology of feminism at the beginning of the 21st century. The main versions of classical feminism are characterized: liberal, Marxist and radical. There is a close connection between the origins of feminism and Marxism, but even in the early period the interaction of these ideological and political movements was problematic. There is also an interaction of feminism with new social movements in the West in the 20th century. The contradictory consequences of the development of the women's movement for the ideology of feminism are noted: on the one hand, the actualization of the feminist agenda in Western countries created the conditions for significant successes in protecting women's rights and recognizing feminism as a real political force, on the other hand, these same successes reduced the relevance of the liberal version of feminism. Recent developments in Europe have a significant impact on the feminist agenda. Globalization and, in particular, the migration crisis of the 2010s are considered as one of the new factors in the ideological dynamics of feminism. The influx of migrants from Muslim countries not only places a burden on state budgets and reduces the level of security of life on the continent, but also erodes the civilizational identity of European society. Muslim migrants do not seek to integrate into European society, often ignore the fundamental values of European civilization, and above all, women's equality. This situation creates incentives not only to renew the political goals of feminists, but also to revise the ideological foundations of their ideology itself. In particular, it is possible to move away from the traditional reliance on left-wing political slogans and replace the popular Marxist phraseology among radical Islamists with values related to the protection of democratic gains of European society.

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