5,079 research outputs found
The Bulgarian monarchy: a politically motivated revision of a historical image in a post-socialist transitional society
Book description: The relationship between states, societies, and individuals in Central and Eastern Europe has been characterised by periods of change and redefinition. The current political, economic, social and cultural climate necessitates a discussion of these issues, both past and present. It is this theme which the proposed publication intends to discuss using a selection of papers given at the 5 th Annual Postgraduate Conference on Central and Eastern Europe held at the UCL School of Slavonic and East European Studies (SSEES) in 2003. The papers represent work from young international scholars from Europe and North America writing on Central and Eastern Europe. The book consists of seven papers and develops an interdisciplinary framework reflecting the range of topics discussed during the conference. It embraces the regional breadth of Central and Eastern Europe containing analyses of Russia, the former Soviet Republics, Central Europe and South Eastern Europe. The papers chosen cover a variety of fields and adopt a corresponding range of approaches with a view to assessing from a multidisciplinary perspective the relationship between state, society and individuals. The papers in the book have been ordered chronologically. The volume starts with an analysis by Julia Mannherz of social conflict in late imperial Russia and moves on to Sergei Zhuk’s discussion of the Stundist movement in Ukraine. The third paper from Stefan Detchev is a discussion of the late-nineteenth-century politics of commemoration surrounding the Bulgarian war of independence. The theme of the politics of commemoration is also present in Andrzej Michalczyk’s analysis of the commemoration of the plebiscite in Silesia by Germans and Poles during the interwar period. Michalczyk examines how a shared event is commemorated and interpreted differently by the two national groups. The idea of common and shared histories is further developed by Rüdiger Ritter in his study of the history and the historiography of post-Communist Poland, Belarus and Lithuania. The move into the contemporary period is completed in the final two papers. The use of historical imagery for political purposes is explored in Markus Wien’s study of the King Simeon II Party in Bulgaria as well as the way in which the historical image of the monarchy has been changed for political purposes during the transition from communism to democracy. The final paper by Maria Aluchna continues the discussion of the process of transition by examining the economic transformation from a communist command economic system to a modern capitalist economy
Holographic confinement in inhomogenous backgrounds
As noted by Witten, compactifying a -dimensional holographic CFT on an
gives a class of -dimensional confining theories with gravity
duals. The prototypical bulk solution dual to the ground state is a double Wick
rotation of the AdS Schwarzschild black hole known as the AdS soliton.
We generalize such examples by allowing slow variations in the size of the
, and thus in the confinement scale. Coefficients governing the second
order response of the system are computed for using a
derivative expansion closely related to the fluid-gravity correspondence. The
primary physical results are that i) gauge-theory flux tubes tend to align
orthogonal to gradients and along the eigenvector of the Hessian with the
lowest eigenvalue, ii) flux tubes aligned orthogonal to gradients are attracted
to gradients for but repelled by gradients for , iii) flux
tubes are repelled by regions where the second derivative along the tube is
large and positive but are attracted to regions where the eigenvalues of the
Hessian are large and positive in directions orthogonal to the tube, and iv)
for , inhomogeneities act to raise the total energy of the confining
vacuum above its zeroth order value.Comment: 16 pages, 6 figures, typos correcte
The Torus Operator in Holography
We consider the non-local operator defined in 2-dimensional
CFTs by the path integral over a torus with two punctures. Using the AdS/CFT
correspondence, we study the spectrum and ground state of this operator in
holographic such CFTs in the limit of large central charge . In one region
of moduli space, we argue that the operator retains a finite gap and has a
ground state that differs from the CFT vacuum only by order one corrections. In
this region the torus operator is much like the cylinder operator. But in
another region of moduli space we find a puzzle. Although our is
of the manifestly positive form , studying the most tractable
phases of suggests that has
negative eigenvalues. It seems clear that additional phases must become
relevant at large , perhaps leading to novel behavior associated with a
radically different ground state or a much higher density of states. By
studying the action of two such torus operators on the CFT ground state, we
also provide evidence that, even at large , the relevant bulk saddles have
surfaces with small genus.Comment: 42 pages, 24 figures, introduction rewritten for clarity, appendix
adde
Adiabatic corrections to holographic entanglement in thermofield doubles and confining ground states
We study entanglement in states of holographic CFTs defined by Euclidean path
integrals over geometries with slowly varying metrics. In particular, our CFT
spacetimes have fibers whose size varies along one direction () of
an base. Such examples respect an
Euclidean symmetry. Treating the direction as time leads to a thermofield
double state on a spacetime with adiabatically varying redshift, while treating
another direction as time leads to a confining ground state with slowly varying
confinement scale. In both contexts the entropy of slab-shaped regions defined
by exhibits well-known phase transitions at length scales characterizing the CFT entanglements. For the thermofield double, the
numerical coefficients governing the effect of variations in on the
transition are surprisingly small and exhibit an interesting change of sign:
gradients reduce for but increase for .
This means that, while for general they significantly increase
the mutual information of opposing slabs as one would expect, for
gradients cause a small decrease near the phase transition. In contrast, for
the confining ground states gradients always decrease , with the
effect becoming more pronounced in higher dimensions.Comment: 32 pages, 16 figures, typos fixed and reg. procedure refine
Quantization and the Issue of Time for Various Two-Dimensional Models of Gravity
It is shown that the models of 2D Liouville Gravity, 2D Black Hole- and
-Gravity are {\em embedded} in the Katanaev-Volovich model of
2D NonEinsteinian Gravity. Different approaches to the formulation of a
quantum theory for the above systems are then presented: The Dirac constraints
can be solved exactly in the momentum representation, the path integral can be
integrated out, and the constraint algebra can be {\em explicitely} canonically
abelianized, thus allowing also for a (superficial) reduced phase space
quantization. Non--trivial dynamics are obtained by means of time dependent
gauges. All of these approaches lead to the {\em same} finite dimensional
quantum mechanical system.Comment: 4 pages, LaTeX, Talk given at the Journ\'ees Relativistes '93,
TUW930
All Symmetries of Non-Einsteinian Gravity in
The covariant form of the field equations for two--dimensional --gravity
with torsion as well as its Hamiltonian formulation are shown to suggest the
choice of the light--cone gauge. Further a one--to--one correspondence between
the Hamiltonian gauge symmetries and the diffeomorphisms and local Lorentz
transformations is established, thus proving that there are no hidden local
symmetries responsible for the complete integrability of the model. Finally the
constraint algebra is shown to have no quantum anomalies so that Dirac's
quantization should be applicable.Comment: LaTex, 16 pages, TUW9207, (Some smaller corrections, cross-references
updated
Handlebody phases and the polyhedrality of the holographic entropy cone
The notion of a holographic entropy cone has recently been introduced and it
has been proven that this cone is polyhedral. However, the original definition
was fully geometric and did not strictly require a holographic duality. We
introduce a new definition of the cone, insisting that the geometries used for
its construction should be dual to states of a CFT. As a result, the
polyhedrality of this holographic cone does not immediately follow. A numerical
evaluation of the Euclidean action for the geometries that realize extremal
rays of the original cone indicates that these are subdominant bulk phases of
natural path integrals. The result challenges the expectation that such
geometries are in fact dual to CFT states.Comment: 20 pages, 7 figures, minor change, added ref, published versio
Holographic Holes and Differential Entropy
Recently, it has been shown by Balasubramanian et al. and Myers et al. that
the Bekenstein-Hawking entropy formula evaluated on certain closed surfaces in
the bulk of a holographic spacetime has an interpretation as the differential
entropy of a particular family of intervals (or strips) in the boundary theory.
We first extend this construction to bulk surfaces which vary in time. We then
give a general proof of the equality between the gravitational entropy and the
differential entropy. This proof applies to a broad class of holographic
backgrounds possessing a generalized planar symmetry and to certain classes of
higher-curvature theories of gravity. To apply this theorem, one can begin with
a bulk surface and determine the appropriate family of boundary intervals by
considering extremal surfaces tangent to the given surface in the bulk.
Alternatively, one can begin with a family of boundary intervals; as we show,
the differential entropy then equals the gravitational entropy of a bulk
surface that emerges from the intersection of the neighboring entanglement
wedges, in a continuum limit.Comment: 62 pages; v2: minor improvements to presentation, references adde
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