Minimal Submanifolds asymptotic to AdS4xS2 in AdS5xS5

In this work, as an attempt in understanding the interplay between deformations of the external and internal spaces associated with the probe-brane embedding submanifold, we construct the zero-temperature phase diagram for the coupled phase between two two-dimensional defects stacked parallel in a four-dimensional ambient spacetime. Different UV parameters are turned on for different defects. We study the system in the quenched strong coupling limit, using holography with probe brane approximation, realized explicitly through the D3/D5 system. This coupled phase is holographic dual to the presence of spontaneous symmetry breaking of the individual ultraviolet flavor symmetries associated with the double heterostructure of the defect layers. We characterize this solution by its infrared geometric data, and present the numerical result showing a first-order phase transition between the asymmetrically coupled phase and the more mundane decoupled phase.Comment: 12 pages, 4 figure

Entanglement Entropy for Probe Branes

We give a prescription for calculating the entanglement entropy in holographic probe brane systems by systematically taking the leading order backreaction of the probe brane into account. We find a simple compact double integral formula, which is insensitive to many details of the backreaction, most notably the internal space or the non-metric fields sourced by the probe. We validate our method by comparing to exact results in solvable toy models. We also determine the entanglement entropies for a sphere and a strip in the top-down D3/D7 and D3/D5 system. For the sphere the entanglement entropy has also been obtained by other methods and we find perfect agreement.Comment: 31 page

From Maxwell-Chern-Simons theory in AdS3AdS_3 towards hydrodynamics in 1+1 dimensions

We study Abelian Maxwell-Chern-Simons theory in three-dimensional $AdS$ black hole backgrounds for both integer and non-integer Chern-Simons coupling. Such theories can be derived from various string theory constructions, which we review in the present work. In particular we find exact solutions in the low frequency, low momentum limit, $\omega, k \ll T$(hydrodynamic limit). Using the holographic principle, we translate our results into correlation functions of vector and scalar operators in the dual strongly coupled 1+1-dimensional quantum field theory with a chiral anomaly at non-zero temperature $T$. Starting from the conformal case we show applicability of the hydrodynamic limit and discuss extensions to the non-conformal case. Correlation functions in the conformal case are compared to an exact field theoretic computation.Comment: 41 pages + appendix, 4 figures, 1 tabl

The LPM effect in sequential bremsstrahlung 2: factorization

The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. In this paper, we continue analysis of the case when the coherence lengths of two consecutive splitting processes overlap (which is important for understanding corrections to standard treatments of the LPM effect in QCD), avoiding soft-gluon approximations. In particular, this paper analyzes the subtle problem of how to precisely separate overlapping double splitting (e.g.\ overlapping double bremsstrahlung) from the case of consecutive, independent bremsstrahlung (which is the case that would be implemented in a Monte Carlo simulation based solely on single splitting rates). As an example of the method, we consider the rate of real double gluon bremsstrahlung from an initial gluon with various simplifying assumptions (thick media; $\hat q$ approximation; large $N_c$; and neglect for the moment of processes involving 4-gluon vertices) and explicitly compute the correction $\Delta\,d\Gamma/dx\,dy$ due to overlapping formation times.Comment: 59 pages, 37 figures. The major changes from v1: new section I.A.4 added to give kinetic theory analogy to better explain the importance of the subtraction defining Delta[d(Gamma)/dx dy]; new appendix F added to compare/contrast with issues raised by Blaizot, Dominguez, Iancu, and Mehtar-Tani [22

The LPM effect in sequential bremsstrahlung: dimensional regularization

The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. Of recent interest is the case when the coherence lengths of two consecutive splitting processes overlap (which is important for understanding corrections to standard treatments of the LPM effect in QCD). In previous papers, we have developed methods for computing such corrections without making soft-gluon approximations. However, our methods require consistent treatment of canceling ultraviolet (UV) divergences associated with coincident emission times, even for processes with tree-level amplitudes. In this paper, we show how to use dimensional regularization to properly handle the UV contributions. We also present a simple diagnostic test that any consistent UV regularization method for this problem needs to pass.Comment: 59 pages, 8 figures [main change from v1: addition of the new appendix B summarizing more about use of the i*epsilon prescription in earlier work

Flavored N=4 SYM -- a highly entangled quantum liquid

We study N=4 SYM theory coupled to fundamental N=2 hypermultiplets in a state of finite charge density. The setup can be described holographically as a configuration of D3 and D7 branes with a non-trivial worldvolume gauge field on the D7. The phase has been identified as a new form of quantum liquid, where certain properties are those of a Fermi liquid while others are clearly distinct. We focus on the entanglement among the flavors, as quantified by the entanglement entropy. The expectation for a Fermi liquid would be a logarithmic enhancement of the area law, but we find a more drastic enhancement instead. The leading contributions are volume terms with a non-trivial shape dependence, signaling extensive entanglement among the flavors. At finite temperature these correlations are confined to a region of size given by the inverse temperature.Comment: 16 pages, 2 figures; published version, references adde

Out-of-hospital Cardiac Arrest in the Elderly

SummaryBackgroundTo investigate the characteristics of out-of-hospital cardiac arrest (OHCA) in the elderly, we retrospectively studied a 6-month series of cases in an emergency department (ED) of a medical center in northern Taiwan.MethodsThere were 145 OHCA cases sent to our ED from January 1, 2007 to June 30, 2007. Of these, 28 traumarelated and five pediatric cases were excluded, and 112 cases were eventually enrolled into our study. The 112 cases were divided into an elderly group (≥ 65 years) of 81 cases and a non-elderly group of 31 cases. There were 64 males and 48 females (male/female ratio, 1.33:1) aged 24–99 years. We collected the laboratory data and made comparisons between the elderly and non-elderly group in arterial blood gas, hemoglobin, potassium, glucose, and troponin I. We used the statistical software SPSS version 11.5.0 (SPSS Inc., Chicago, IL, USA) with t test analysis. The clinical significance was set at p < 0.05.ResultsReturn of spontaneous circulation (ROSC) occurred in 46 cases (41%) after standard resuscitation by advanced cardiac life support. The elderly group had a higher ROSC rate than the non-elderly group, but this was not significant (44% vs. 32%; p = 0.335). The elderly group had less acidosis, less hypercapnia, less hyperkalemia, less hyperglycemia and a higher rate of elevated troponin I than the non-elderly group, but the differences were not significant. The elderly group had significantly lower hemoglobin levels than the non-elderly group (10.52 ± 3.04 vs. 12.6 ± 3.32g/dL; p = 0.003). The glucose levels of the ROSC group were significantly higher than the non-ROSC group in the elderly (230.14 ± 130.4 vs. 195.1 ± 147.7mg/dL; p = 0.049). In the group of acute coronary syndrome (ACS)-related OHCA, the ROSC rate in the elderly group was significantly higher than that of the non-elderly (54.2% vs. 40%; p = 0.014). The elderly group had a slightly lower rate of survival than the non-elderly group (7.4% vs. 9.7%; p = 0.159).ConclusionThe elderly OHCA cases had an anemic status. The elderly had a higher ROSC rate in cases with relative hyperglycemia and ACS-related OHCA. This finding provides us with the theory of trialing administration of glucose water during resuscitation in OHCA cases