172 research outputs found
Non-Markovian decoherence of a two-level system in a Lorentzian bosonic reservoir and a stochastic environment with finite correlation time
In this paper we investigate non-Markovian evolution of a two-level system (qubit) in a bosonic bath under influence of an external classical fluctuating environment. The interaction with the bath has the Lorentzian spectral density, and the fluctuating environment (stochastic field) is represented by a set of Ornstein-Uhlenbeck processes. Each of the subenvironments of the composite environment is able to induce non-Markovian dynamics of the two-level system. By means of the numerically exact method of hierarchical equations of motion, we study steady states of the two-level system, evolution of the reduced density matrix and the equilibrium emission spectra in dependence on the frequency cutoffs and the coupling strengths of the subenvironments. Additionally, we investigate the impact of the rotating wave approximation (RWA) for the interaction with the bath on accuracy of the results
BPS Electromagnetic Waves on Giant Gravitons
We find new 1/8-BPS giant graviton solutions in , carrying
three angular momenta along , and investigate their properties.
Especially, we show that nonzero worldvolume gauge fields are admitted
preserving supersymmetry. These gauge field modes can be viewed as
electromagnetic waves along the compact D3 brane, whose Poynting vector
contributes to the BPS angular momenta. We also analyze the (nearly-)spherical
giant gravitons with worldvolume gauge fields in detail. Expressing the
in Hopf fibration ( fibred over ), the wave propagates along the
fiber.Comment: 25 pages, no figures, v2: references adde
Holography in 4D (Super) Higher Spin Theories and a Test via Cubic Scalar Couplings
The correspondences proposed previously between higher spin gauge theories
and free singleton field theories were recently extended into a more complete
picture by Klebanov and Polyakov in the case of the minimal bosonic theory in
D=4 to include the strongly coupled fixed point of the 3d O(N) vector model.
Here we propose an N=1 supersymmetric version of this picture. We also
elaborate on the role of parity in constraining the bulk interactions, and in
distinguishing two minimal bosonic models obtained as two different consistent
truncations of the minimal N=1 model that retain the scalar or the
pseudo-scalar field. We refer to these models as the Type A and Type B models,
respectively, and conjecture that the latter is holographically dual to the 3d
Gross-Neveu model. In the case of the Type A model, we show the vanishing of
the three-scalar amplitude with regular boundary conditions. This agrees with
the O(N) vector model computation of Petkou, thereby providing a non-trivial
test of the Klebanov-Polyakov conjecture.Comment: 30p
Dual giant gravitons in AdS Y (Sasaki-Einstein)
We consider BPS motion of dual giant gravitons on Ad where
represents a five-dimensional Sasaki-Einstein manifold. We find that the
phase space for the BPS dual giant gravitons is symplectically isomorphic to
the Calabi-Yau cone over , with the K\"{a}hler form identified with the
symplectic form. The quantization of the dual giants therefore coincides with
the K\"{a}hler quantization of the cone which leads to an explicit
correspondence between holomorphic wavefunctions of dual giants and
gauge-invariant operators of the boundary theory. We extend the discussion to
dual giants in where is a seven-dimensional
Sasaki-Einstein manifold; for special motions the phase space of the dual
giants is symplectically isomorphic to the eight-dimensional Calabi-Yau cone.Comment: 14 pages. (v2) typo's corrected; factors of AdS radius reinstated for
clarity; remarks about dual giant wavefunctions in T^{1,1} expanded and put
in a new subsectio
Counting 1/8-BPS Dual-Giants
We count 1/8-BPS states in type IIB string theory on AdS_5 x S^5 background
which carry three independent angular momenta on S^5. These states can be
counted by considering configurations of multiple dual-giant gravitons up to N
in number which share at least four supersymmetries. We map this counting
problem to that of counting the energy eigen states of a system of N bosons in
a 3-dimensional harmonic oscillator. We also count 1/8-BPS states with two
independent non-zero spins in AdS_5 and one non-zero angular momentum on S^5 by
considering configurations of arbitrary number of giant gravitons that share at
least four supersymmetries.Comment: 19 page
Оказание медицинской помощи пациентам с акне. Результаты экспертизы качества медицинской помощи
Goal. To obtain information on typical errors in medical aid rendered to acne patients in dermatovenerology dispensaries in St. Petersburg in order to develop measures to improve the quality of medical aid rendered to this group of patients. Materials and methods. The authors conducted a special expert examination of 55 patients with acne who received treatment at St. Petersburg dermatovenerology dispensaries in 2013. The quality of medical aid was assessed using the Automated Expert Examination Technique (hereinafter referred to as AEET). Major results. The percentage of cases when medical aid of due quality was rendered to acne patients was 49%. Treatment and diagnostics errors prevailed in the structure of errors in medical aid. Errors in treatment were mainly a wrong combination of drugs, simultaneous administration of external and systemic antibacterial drugs, delayed comedolytic therapy and pathogenically infeasible therapy. Errors in diagnostics included absence of indications of the form and/or severity of acne. The most important error in the collection of information was absence of gynecology examinations for women to determine whether peroral contraceptives were necessary including in case of the administration of isotretinoin. Conclusion. The similarity of errors in medical aid rendered for acne as well as high percentage of errors relating to medical aid rendered to patients demand the development of consistent measures to improve the quality of medical aid rendered to such patients and repeated expert examination using preliminary (prompt) control of the quality of medical aid.Цель. Получение информации о типичных ошибках оказания медицинской помощи пациентам с акне в кожно-венерологических диспансерах (КВД) Санкт-Петербурга для разработки мер, направленных на улучшение качества медицинской помощи (КМП) данной группе пациентов. Материал и методы. Проведена тематическая экспертиза КМП 55 наблюдений пациентов с акне, которые получали лечение в КВД Санкт-Петербурга в 2013 г. Изучение КМП проводилось с применением Автоматизированной технологии экспертизы КМП. Результаты. Доля случаев оказания медицинской помощи надлежащего качества пациентам с акне составляла 49%. В структуре ошибок оказания медицинской помощи преобладали ошибки лечения и диагноза. Ошибки лечения были представлены преимущественно неверным сочетанием препаратов, наиболее часто одномоментным назначением антибактериальных препаратов для наружного и системного применения, поздним назначением комедолитической терапии, а также применением патогенетически необоснованной терапии. Ошибками постановки диагноза считали отсутствие указаний на форму и/или степень тяжести акне, наиболее важными ошибками сбора информации - отсутствие обследования женщин у гинеколога для решения вопроса о необходимости применения комбинированных оральных контрацептивов, в том числе и при назначении изотретиноина. Заключение. Сходство характера ошибок медицинской помощи при акне, а также их высокий удельный вес при оказании медицинской помощи пациентам требуют разработки системных мероприятий по улучшению КМП этим больным и повторной экспертизы с применением индикаторов промежуточного (оперативного) контроля КМП
At the horizon of a supersymmetric AdS_5 black hole: Isometries and half-BPS giants
The near-horizon geometry of an asymptotically AdS_5 supersymmetric black
hole discovered by Gutowski and Reall is analysed. After lifting the solution
to 10 dimensions, we explicitly solve the Killing spinor equations in both
Poincare and global coordinates. It is found that exactly four supersymmetries
are preserved which is twice the number for the full black hole. The full set
of isometries is constructed and the isometry supergroup is shown to be
SU(1,1|1) X SU(2) X U(3). We further study half-BPS configurations of D3-branes
in the near-horizon geometry in Poincare and global coordinates. Both giant
graviton probes and dual giant graviton probes are found.Comment: 26 pages. v2:Typos corrected, minor change
1/16-BPS Black Holes and Giant Gravitons in the AdS_5 X S^5 Space
We explore 1/16-BPS objects of type IIB string theory in AdS_5 * S^5. First,
we consider supersymmetric AdS_5 black holes, which should be 1/16-BPS and have
a characteristic that not all physical charges are independent. We point out
that the Bekenstein-Hawking entropy of these black holes admits a remarkably
simple expression in terms of (dependent) physical charges, which suggests its
microscopic origin via certain Cardy or Hardy-Ramanujan formula. We also note
that there is an upper bound for the angular momenta given by the electric
charges. Second, we construct a class of 1/16-BPS giant graviton solutions in
AdS_5 * S^5 and explore their properties. The solutions are given by the
intersections of AdS_5 * S^5 and complex 3 dimensional holomorphic hyperspaces
in C^{1+5}, the latter being the zero loci of three holomorphic functions which
are homogeneous with suitable weights on coordinates. We investigate examples
of giant gravitons, including their degenerations to tensionless strings.Comment: 25 pages, no figures, v2: references added, comments added in the
conclusio
AdS Branes Corresponding to Superconformal Defects
We investigate an AdS_4 x L_2 D5-brane in AdS_5 x X_5 space-time, in the
context of AdS/dCFT correspondence. Here, X_5 is a Sasaki-Einstein manifold and
L_2 is a submanifold of X_5. This brane has the same supersymmetry as the
3-dimensional N=1 superconformal symmetry if L_2 is a special Legendrian
submanifold in X_5. In this case, this brane is supposed to correspond to a
superconformal wall defect in 4-dimensional N=4 super Yang-Mills theory. We
construct these new string backgrounds and show they have the correct
supersymmetry, also in the case with non-trivial gauge flux on L_2. The
simplest new example is AdS_4 x T^2 brane in AdS_5 x S^5. We construct the
brane solution expressing the RG flow between two different defects. We also
perform similar analysis for an AdS_3 x L_3 M5-brane in AdS_4 x X_7, for a weak
G_2 manifold X_7 and its submanifold L_3. This system has the same
supersymmetry as 2-dimensional N=(1,0) global superconformal symmetry, if L_3
is an associative submanifold.Comment: 22 pages, LaTeX, 3 figures. v2: typos corrected, references added.
v3: typos correcte
Entropy of near-extremal black holes in AdS_5
We construct the microstates of near-extremal black holes in AdS_5 x S^5 as
gases of defects distributed in heavy BPS operators in the dual SU(N)
Yang-Mills theory. These defects describe open strings on spherical D3-branes
in the S^5, and we show that they dominate the entropy by directly enumerating
them and comparing the results with a partition sum calculation. We display new
decoupling limits in which the field theory of the lightest open strings on the
D-branes becomes dual to a near-horizon region of the black hole geometry. In
the single-charge black hole we find evidence for an infrared duality between
SU(N) Yang-Mills theories that exchanges the rank of the gauge group with an
R-charge. In the two-charge case (where pairs of branes intersect on a line),
the decoupled geometry includes an AdS_3 factor with a two-dimensional CFT
dual. The degeneracy in this CFT accounts for the black hole entropy. In the
three-charge case (where triples of branes intersect at a point), the decoupled
geometry contains an AdS_2 factor. Below a certain critical mass, the
two-charge system displays solutions with naked timelike singularities even
though they do not violate a BPS bound. We suggest a string theoretic
resolution of these singularities.Comment: LaTeX; v2: references and a few additional comments adde
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