Fast Scramblers Of Small Size

We investigate various geometrical aspects of the notion of `optical depth' in the thermal atmosphere of black hole horizons. Optical depth has been proposed as a measure of fast-crambling times in such black hole systems, and the associated optical metric suggests that classical chaos plays a leading role in the actual scrambling mechanism. We study the behavior of the optical depth with the size of the system and find that AdS/CFT phase transitions with topology change occur naturally as the scrambler becomes smaller than its thermal length. In the context of detailed AdS/CFT models based on D-branes, T-duality implies that small scramblers are described in terms of matrix quantum mechanics.Comment: 14 pages, 3 figures. Added reference

Повернення в Ніжин (корпус документів з епістолярію І.Г. Спаського)

Підготовка до друку та переднє слово Наталії ДМИТРЕНКО (Ніжин), коментарі Сергія ЗОЗУЛІ (Київ–Ніжин): Уперше вводиться до наукового обігу корпус джерел з епістолярію українського та російського радянського історика-нумізмата, музейника І.Г. Спаського. Корпус джерел який містить кореспонденцію, отриману відомим науковцем від кореспондентів-ніжинців, і де, здебільшого, відображена “ніжинська тематика” – проблеми збереження культурної спадщини Ніжина, післявоєнного розвитку міста тощо.Подготовка к печати и предисловие Наталии ДМИТРЕНКО (Нежин), комментарии Сергея ЗОЗУЛИ (Киев–Нежин): Впервые вводится в научный оборот корпус источников из эпистолярия украинского и российского советского историка-нумизмата, музейщика И.Г. Спасского. Корпус источников содержит корреспонденцию, полученную известным ученым от корреспондентов-нежинцев, и в котором преимущественно отображена “нежинская тематика” – проблемы сохранения культурного наследия Нежина, послевоенного развития города и т.п.Preparation to the print and preface of Nataliya DMYTRENKO (Nizhyn), comments of Serhiy ZOZULYA (Kyiv–Nizhyn): The corps of sources from the epistolary legacy of the Ukrainian and Russian soviet historiannumismatist and museum worker I.G. Spas’kiy is entered to the scientific appeal in the first time. This corps of sources contains correspondence got the known scientist from Nizhynians and contains mostly “Nizhyn themes” – problems of protect of Nizhyn’s cultural legacy, post-war development of this town etc

Exploring Curved Superspace

We systematically analyze Riemannian manifolds M that admit rigid supersymmetry, focusing on four-dimensional N=1 theories with a U(1)_R symmetry. We find that M admits a single supercharge, if and only if it is a Hermitian manifold. The supercharge transforms as a scalar on M. We then consider the restrictions imposed by the presence of additional supercharges. Two supercharges of opposite R-charge exist on certain fibrations of a two-torus over a Riemann surface. Upon dimensional reduction, these give rise to an interesting class of supersymmetric geometries in three dimensions. We further show that compact manifolds admitting two supercharges of equal R-charge must be hyperhermitian. Finally, four supercharges imply that M is locally isometric to M_3 x R, where M_3 is a maximally symmetric space.Comment: 39 pages; minor change

Weak Field Black Hole Formation in Asymptotically AdS Spacetimes

We use the AdS/CFT correspondence to study the thermalization of a strongly coupled conformal field theory that is forced out of its vacuum by a source that couples to a marginal operator. The source is taken to be of small amplitude and finite duration, but is otherwise an arbitrary function of time. When the field theory lives on $R^{d-1,1}$, the source sets up a translationally invariant wave in the dual gravitational description. This wave propagates radially inwards in $AdS_{d+1}$ space and collapses to form a black brane. Outside its horizon the bulk spacetime for this collapse process may systematically be constructed in an expansion in the amplitude of the source function, and takes the Vaidya form at leading order in the source amplitude. This solution is dual to a remarkably rapid and intriguingly scale dependent thermalization process in the field theory. When the field theory lives on a sphere the resultant wave either slowly scatters into a thermal gas (dual to a glueball type phase in the boundary theory) or rapidly collapses into a black hole (dual to a plasma type phase in the field theory) depending on the time scale and amplitude of the source function. The transition between these two behaviors is sharp and can be tuned to the Choptuik scaling solution in $R^{d,1}$.Comment: 50 pages + appendices, 6 figures, v2: Minor revisions, references adde

Recurrent Plasmacytomas after Allografting in a Patient with Multiple Myeloma

Extramedullary recurrence in multiple myeloma patients has been reported after both autologous and allogeneic hematopoietic cell transplantation and, more recently, after treatment with so-called new drugs with potent antimyeloma activity. Only a very few sizable reports focused on its clinical presentation and its incidence, which may be highly underestimated, and most observations are based on single patients reported from several institutions. Given the unusual sites of recurrence, diagnosis may be rather difficult and delayed treatment may play a relevant role in prognosis. Here we report a case of a myeloma patient, initially treated with an allograft, who enjoyed an eleven-year disease-free remission with very good quality of life. She eventually relapsed first with an extramedullary plasmacytoma in the breast and, two years later, with a right atrial cardiac mass

Supersymmetric QCD: Exact Results and Strong Coupling

We revisit two longstanding puzzles in supersymmetric gauge theories. The first concerns the question of the holomorphy of the coupling, and related to this the possible definition of an exact (NSVZ) beta function. The second concerns instantons in pure gluodynamics, which appear to give sensible, exact results for certain correlation functions, which nonetheless differ from those obtained using systematic weak coupling expansions. For the first question, we extend an earlier proposal of Arkani-Hamed and Murayama, showing that if their regulated action is written suitably, the holomorphy of the couplings is manifest, and it is easy to determine the renormalization scheme for which the NSVZ formula holds. This scheme, however, is seen to be one of an infinite class of schemes, each leading to an exact beta function; the NSVZ scheme, while simple, is not selected by any compelling physical consideration. For the second question, we explain why the instanton computation in the pure supersymmetric gauge theory is not reliable, even at short distances. The semiclassical expansion about the instanton is purely formal; if infrared divergences appear, they spoil arguments based on holomorphy. We demonstrate that infrared divergences do not occur in the perturbation expansion about the instanton, but explain that there is no reason to think this captures all contributions from the sector with unit topological charge. That one expects additional contributions is illustrated by dilute gas corrections. These are infrared divergent, and so difficult to define, but if non-zero give order one, holomorphic, corrections to the leading result. Exploiting an earlier analysis of Davies et al, we demonstrate that in the theory compactified on a circle of radius beta, due to infrared effects, finite contributions indeed arise which are not visible in the formal limit that beta goes to infinity.Comment: 28 pages, two references added, one typo correcte

Exact Results in D=2 Supersymmetric Gauge Theories

We compute exactly the partition function of two dimensional N=(2,2) gauge theories on S^2 and show that it admits two dual descriptions: either as an integral over the Coulomb branch or as a sum over vortex and anti-vortex excitations on the Higgs branches of the theory. We further demonstrate that correlation functions in two dimensional Liouville/Toda CFT compute the S^2 partition function for a class of N=(2,2) gauge theories, thereby uncovering novel modular properties in two dimensional gauge theories. Some of these gauge theories flow in the infrared to Calabi-Yau sigma models - such as the conifold - and the topology changing flop transition is realized as crossing symmetry in Liouville/Toda CFT. Evidence for Seiberg duality in two dimensions is exhibited by demonstrating that the partition function of conjectured Seiberg dual pairs are the same.Comment: 78 pages, LaTeX; v2: small corrections and references added; v3: JHEP version, discussing factorization further in new appendix F; v4: sign corrected for non simply-connected gauge grou

The Omega Deformation From String and M-Theory

We present a string theory construction of Omega-deformed four-dimensional gauge theories with generic values of \epsilon_1 and \epsilon_2. Our solution gives an explicit description of the geometry in the core of Nekrasov and Witten's realization of the instanton partition function, far from the asymptotic region of their background. This construction lifts naturally to M-theory and corresponds to an M5-brane wrapped on a Riemann surface with a selfdual flux. Via a 9-11 flip, we finally reinterpret the Omega deformation in terms of non-commutative geometry. Our solution generates all modified couplings of the \Omega-deformed gauge theory, and also yields a geometric origin for the quantum spectral curve of the associated quantum integrable system.Comment: LaTeX, 35 pages, 1 figure. Appendix on couplings of hypermultiplets in N=4 SYM adde

Supergravity for Effective Theories

Higher-derivative operators are central elements of any effective field theory. In supersymmetric theories, these operators include terms with derivatives in the K\"ahler potential. We develop a toolkit for coupling such supersymmetric effective field theories to supergravity. We explain how to write the action for minimal supergravity coupled to chiral superfields with arbitrary numbers of derivatives and curvature couplings. We discuss two examples in detail, showing how the component actions agree with the expectations from the linearized description in terms of a Ferrara-Zumino multiplet. In a companion paper, we apply the formalism to the effective theory of inflation.Comment: 26 page

Accelerating universe emergent from the landscape

We propose that the existence of the string landscape suggests the universe can be in a quantum glass state, where an extremely large viscosity is generated, and long distance dynamics slows down. At the same time, the short distance dynamics is not altered due to the separation of time scales. This scenario can help to understand some controversies in cosmology, for example the natural existence of slow roll inflation and dark energy in the landscape, the apparent smallness of the cosmological constant. We see also that moduli stabilization is no longer necessary. We further identify the glass transition point, where the viscosity diverges, as the location of the cosmic horizon. We try to reconstruct the geometry of the accelerating universe from the structure of the landscape, and find that the metric should have an infinite jump when crossing the horizon. We predict that the static coordinate metric for dS space breaks down outside the horizon.Comment: 20 pages, no figures, harvma