552 research outputs found
Smart Institutions for Smart Cities
Smart cities employ creativity of the population for innovations supporting social and economic development. In this context, this paper explores the role of framework conditions on special supply effects of university hospitals, which can invite further research institutions for intense collaboration, thereby stimulating innovations. The case study, comparing a hospital in Russia with one in Germany, is based on the concept of the employment multiplier. The results show that exogenously given, but, more importantly, also modifiable framework conditions lead to large differences regarding the employment multiplier. Thus, it should be the concern of smart cities to make smart use of their institutions, such as university hospitals, by adjusting the conditions, under which they are operating. © 2018 Institute of Physics Publishing. All rights reserved
On The Phase Structure and Thermodynamic Geometry of R-Charged Black Holes
We study the phase structure and equilibrium state space geometry of
R-charged black holes in , 4 and 7 and the corresponding rotating ,
and branes. For various charge configurations of the compact black
holes in the canonical ensemble we demonstrate new liquid-gas like phase
coexistence behaviour culminating in second order critical points. The critical
exponents turn out to be the same as that of four dimensional asymptotically
AdS black holes in Einstein Maxwell theory. We further establish that the
regions of stability for R-charged black holes are, in some cases, more
constrained than is currently believed, due to properties of some of the
response coefficients. The equilibrium state space scalar curvature is
calculated for various charge configurations, both for the case of compact as
well as flat horizons and its asymptotic behaviour with temperature is
established.Comment: 1 + 33 pages, LaTeX, 25 figures. References adde
On the Thermodynamic Geometry and Critical Phenomena of AdS Black Holes
In this paper, we study various aspects of the equilibrium thermodynamic
state space geometry of AdS black holes. We first examine the
Reissner-Nordstrom-AdS (RN-AdS) and the Kerr-AdS black holes. In this context,
the state space scalar curvature of these black holes is analysed in various
regions of their thermodynamic parameter space. This provides important new
insights into the structure and significance of the scalar curvature. We
further investigate critical phenomena, and the behaviour of the scalar
curvature near criticality, for KN-AdS black holes in two mixed ensembles,
introduced and elucidated in our earlier work arXiv:1002.2538 [hep-th]. The
critical exponents are identical to those in the RN-AdS and Kerr-AdS cases in
the canonical ensemble. This suggests an universality in the scaling behaviour
near critical points of AdS black holes. Our results further highlight
qualitative differences in the thermodynamic state space geometry for electric
charge and angular momentum fluctuations of these.Comment: 1 + 37 Pages, LaTeX, includes 31 figures. A figure and a
clarification added
An Exact Fluctuating 1/2-BPS Configuration
This work explores the role of thermodynamic fluctuations in the two
parameter giant and superstar configurations characterized by an ensemble of
arbitrary liquid droplets or irregular shaped fuzzballs. Our analysis
illustrates that the chemical and state-space geometric descriptions exhibit an
intriguing set of exact pair correction functions and the global correlation
lengths. The first principle of statistical mechanics shows that the possible
canonical fluctuations may precisely be ascertained without any approximation.
Interestingly, our intrinsic geometric study exemplifies that there exist exact
fluctuating 1/2-BPS statistical configurations which involve an ensemble of
microstates describing the liquid droplets or fuzzballs. The Gaussian
fluctuations over an equilibrium chemical and state-space configurations
accomplish a well-defined, non-degenerate, curved and regular intrinsic
Riemannian manifolds for all physically admissible domains of black hole
parameters. An explicit computation demonstrates that the underlying chemical
correlations involve ordinary summations, whilst the state-space correlations
may simply be depicted by standard polygamma functions. Our construction
ascribes definite stability character to the canonical energy fluctuations and
to the counting entropy associated with an arbitrary choice of excited boxes
from an ensemble of ample boxes constituting a variety of Young tableaux.Comment: Minor changes, added references, 30 pages, 4 figures, PACS numbers:
04.70.-s: Physics of black holes; 04.70.-Bw: Classical black holes; 04.50.Gh
Higher-dimensional black holes, black strings, and related objects; 04.60.Cf
Gravitational aspects of string theory, accepted for publication in JHE
Expanding the palette of phenanthridinium cations
5,6-Disubstituted phenanthridinium cations have a range of redox, fluorescence and biological properties. Some properties rely on phenanthridiniums intercalating into DNA, but the use of these cations as exomarkers for the reactive oxygen species (ROS), superoxide, and as inhibitors of acetylcholine esterase (AChE) do not require intercalation. A versatile modular synthesis of 5,6-disubstituted phenanthridiniums that introduces diversity by Suzuki–Miyaura coupling, imine formation and microwave-assisted cyclisation is presented. Computational modelling at the density functional theory (DFT) level reveals that the novel displacement of the aryl halide by an acyclic N-alkylimine proceeds by an SNAr mechanism rather than electrocyclisation. It is found that the displacement of halide is concerted and there is no stable Meisenheimer intermediate, provided the calculations consistently use a polarisable solvent model and a diffuse basis set
Thermodynamics of a class of non-asymptotically flat black holes in Einstein-Maxwell-Dilaton theory
We analyse in detail the thermodynamics in the canonical and grand canonical
ensembles of a class of non-asymptotically flat black holes of the
Einstein-(anti) Maxwell-(anti) Dilaton theory in 4D with spherical symmetry. We
present the first law of thermodynamics, the thermodynamic analysis of the
system through the geometrothermodynamics methods, Weinhold, Ruppeiner,
Liu-Lu-Luo-Shao and the most common, that made by the specific heat. The
geometric methods show a curvature scalar identically zero, which is
incompatible with the results of the analysis made by the non null specific
heat, which shows that the system is thermodynamically interacting, does not
possess extreme case nor phase transition. We also analyse the local and global
stability of the thermodynamic system, and obtain a local and global stability
for the normal case for 0<\gamma<1 and for other values of \gamma, an unstable
system. The solution where \gamma=0 separates the class of locally and globally
stable solutions from the unstable ones.Comment: 18 pages, version accepted for publication in General Relativity and
Gravitatio
Neutral Pions and Eta Mesons as Probes of the Hadronic Fireball in Nucleus-Nucleus Collisions around 1A GeV
Chemical and thermal freeze-out of the hadronic fireball formed in symmetric
collisions of light, intermediate-mass, and heavy nuclei at beam energies
between 0.8A GeV and 2.0A GeV are discussed in terms of an equilibrated,
isospin-symmetric ideal hadron gas with grand-canonical baryon-number
conservation. For each collision system the baryochemical potential mu_B and
the chemical freeze-out temperature T_c are deduced from the inclusive neutral
pion and eta yields which are augmented by interpolated data on deuteron
production. With increasing beam energy mu_B drops from 800 MeV to 650 MeV,
while T_c rises from 55 MeV to 90 MeV. For given beam energy mu_B grows with
system size, whereas T_c remains constant. The centrality dependence of the
freeze-out parameters is weak as exemplified by the system Au+Au at 0.8A GeV.
For the highest beam energies the fraction of nucleons excited to resonance
states reaches freeze-out values of nearly 15 %, suggesting resonance densities
close to normal nuclear density at maximum compression. In contrast to the
particle yields, which convey the status at chemical freeze-out, the shapes of
the related transverse-mass spectra do reflect thermal freeze-out. The observed
thermal freeze-out temperatures T_th are equal to or slightly lower than T_c,
indicative of nearly simultaneous chemical and thermal freeze-out.Comment: 42 pages, 12 figure
Thermodynamic Geometry and Phase Transitions in Kerr-Newman-AdS Black Holes
We investigate phase transitions and critical phenomena in Kerr-Newman-Anti
de Sitter black holes in the framework of the geometry of their equilibrium
thermodynamic state space. The scalar curvature of these state space Riemannian
geometries is computed in various ensembles. The scalar curvature diverges at
the critical point of second order phase transitions for these systems.
Remarkably, however, we show that the state space scalar curvature also carries
information about the liquid-gas like first order phase transitions and the
consequent instabilities and phase coexistence for these black holes. This is
encoded in the turning point behavior and the multi-valued branched structure
of the scalar curvature in the neighborhood of these first order phase
transitions. We re-examine this first for the conventional Van der Waals
system, as a preliminary exercise. Subsequently, we study the Kerr-Newman-AdS
black holes for a grand canonical and two "mixed" ensembles and establish novel
phase structures. The state space scalar curvature bears out our assertion for
the first order phase transitions for both the known and the new phase
structures, and closely resembles the Van der Waals system.Comment: 1 + 41 pages, LaTeX, 46 figures. Discussions, clarifications and
references adde
State-space Manifold and Rotating Black Holes
We study a class of fluctuating higher dimensional black hole configurations
obtained in string theory/ -theory compactifications. We explore the
intrinsic Riemannian geometric nature of Gaussian fluctuations arising from the
Hessian of the coarse graining entropy, defined over an ensemble of brane
microstates. It has been shown that the state-space geometry spanned by the set
of invariant parameters is non-degenerate, regular and has a negative scalar
curvature for the rotating Myers-Perry black holes, Kaluza-Klein black holes,
supersymmetric black holes, - configurations and the
associated BMPV black holes. Interestingly, these solutions demonstrate that
the principal components of the state-space metric tensor admit a positive
definite form, while the off diagonal components do not. Furthermore, the ratio
of diagonal components weakens relatively faster than the off diagonal
components, and thus they swiftly come into an equilibrium statistical
configuration. Novel aspects of the scaling property suggest that the
brane-brane statistical pair correlation functions divulge an asymmetric
nature, in comparison with the others. This approach indicates that all above
configurations are effectively attractive and stable, on an arbitrary
hyper-surface of the state-space manifolds. It is nevertheless noticed that
there exists an intriguing relationship between non-ideal inter-brane
statistical interactions and phase transitions. The ramifications thus
described are consistent with the existing picture of the microscopic CFTs. We
conclude with an extended discussion of the implications of this work for the
physics of black holes in string theory.Comment: 44 pages, Keywords: Rotating Black Holes; State-space Geometry;
Statistical Configurations, String Theory, M-Theory. PACS numbers: 04.70.-s
Physics of black holes; 04.70.Bw Classical black holes; 04.70.Dy Quantum
aspects of black holes, evaporation, thermodynamics; 04.50.Gh
Higher-dimensional black holes, black strings, and related objects. Edited
the bibliograph
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