21,278 research outputs found
Charged black rings in supergravity with a single non-zero gauge field
General charged black ring solution with two angular momenta, a charge and a
dipole charge is found by the inverse scattering method. The solution is
presented in a relatively concise form in which its symmetries are manifest.
The regularity conditions are found and the physical characteristics of the
regular solution are expressed via its parameters.Comment: Misprints corrected, references added, JHEP forma
Holographic Superconductors
A holographic model of superconductors based on the action proposed by
Benini, Herzog, and Yarom [arXiv:1006.0731] is studied. This model has a
charged spin two field in an AdS black hole spacetime. Working in the probe
limit, the normalizable solution of the spin two field in the bulk gives rise
to a superconducting order parameter at the boundary of the AdS. We
calculate the fermion spectral function in this\ superconducting background and
confirm the existence of fermi arcs for non-vanishing Majorana couplings. By
changing the relative strength of the and condensations, the
position and the size of the fermi arcs are changed. When , the
spectrum becomes isotropic and the spectral function is s-wave like. By
changing the fermion mass, the fermi momentum is changed. We also calculate the
conductivity for these holographic superconductors where time reversal
symmetry has been broken spontaneously. A non-vanishing Hall conductivity is
obtained even without an external magnetic field.Comment: 24 pages,17 figures, Add more discussions on hall conductivity, two
new figures, Matched with published versio
Fermion correlators in non-abelian holographic superconductors
We consider fermion correlators in non-abelian holographic superconductors.
The spectral function of the fermions exhibits several interesting features
such as support in displaced Dirac cones and an asymmetric distribution of
normal modes. These features are compared to similar ones observed in angle
resolved photoemission experiments on high T_c superconductors. Along the way
we elucidate some properties of p-wave superconductors in AdS_4 and discuss the
construction of SO(4) superconductors.Comment: 49 pages, 11 figure
Photoluminescence and lasing characteristics of single nonpolar GaN microwires
published_or_final_versio
Domain Wall Holography for Finite Temperature Scaling Solutions
We investigate a class of near-extremal solutions of Einstein-Maxwell-scalar
theory with electric charge and power law scaling, dual to charged IR phases of
relativistic field theories at low temperature. These are exact solutions of
theories with domain wall vacua; hence, we use nonconformal holography to
relate the bulk and boundary theories. We numerically construct a global
interpolating solution between the IR charged solutions and the UV domain wall
vacua for arbitrary physical choices of Lagrangian parameters. By passing to a
conformal frame in which the domain wall metric becomes that of AdS, we uncover
a generalized scale invariance of the IR scaling solution, indicating a
connection to the physics of Lifshitz fixed points. Finally, guided by
effective field theoretic principles and the physics of nonconformal D-branes,
we argue for the applicability of domain wall holography even in theories with
AdS critical points, namely those theories for which a scalar potential is
dominated by a single exponential term over a large range
Holographic Superconductors with Power-Maxwell field
With the Sturm-Liouville analytical and numerical methods, we investigate the
behaviors of the holographic superconductors by introducing a complex charged
scalar field coupled with a Power-Maxwell field in the background of
-dimensional Schwarzschild AdS black hole. We note that the Power-Maxwell
field takes the special asymptotical solution near boundary which is different
from all known cases. We find that the larger power parameter for the
Power-Maxwell field makes it harder for the scalar hair to be condensated. We
also find that, for different , the critical exponent of the system is still
1/2, which seems to be an universal property for various nonlinear
electrodynamics if the scalar field takes the form of this paper.Comment: 14 pages, 1 figure, and 2 table
Flavor brane on the baryonic branch of moduli space
We study an extra flavor in the cascading SU((k+1)M)xSU(k M) gauge theory by
adding probe D7-brane to the geometry. By finding a solution to the
kappa-symmetry equation we establish that the D7-brane is mutually
supersymmetric with the background everywhere on the baryonic branch of moduli
space. We also discuss possible applications of this result.Comment: 15 pages; v2 typo corrected, references adde
Holographic Correlation Functions for Open Strings and Branes
In this paper, we compute holographically the two-point and three-point
functions of giant gravitons with open strings. We consider the maximal giant
graviton in and the string configurations corresponding to the ground
states of Z=0 and Y=0 open spin chain, and the spinning string in AdS
corresponding to the derivative type impurities in Y=0 or Z=0 open spin chain
as well. We treat the D-brane and open string contribution separately and find
the corresponding D3-brane and string configurations in bulk which connect the
composite operators at the AdS boundary. We apply a new prescription to
treat the string state contribution and find agreements for the two-point
functions. For the three-point functions of two giant gravitons with open
strings and one certain half-BPS chiral primary operator, we find that the
D-brane contributions to structure constant are always vanishing and the open
string contribution for the Y=0 ground state is in perfect match with the
prediction in the free field limit.Comment: 25 page
Virologically confirmed population-based burden of hospitalization caused by influenza a and b among children in Hong Kong
Background. We sought to determine the virologically confirmed hospitalization rates associated with influenza virus infection among Hong Kong children. Methods. Patients <18 years of age who lived on Hong Kong Island (a separate island within Hong Kong) and were admitted to either of the only 2 public hospitals on the island for a febrile acute respiratory infection on 1 fixed day of the week in each hospital from October 2003 through September 2006 were prospectively recruited. These 2 hospitals together accounted for 72.5% of all general pediatric admissions in Hong Kong Island with a known population denominator. Nasopharyngeal aspirates were obtained from all recruited patients and were tested for influenza A and influenza B viruses by direct antigen detection and culture. Results. All cases of influenza A during 2003-2004 were caused by H3N2 virus, whereas 85.7% of cases during 2004-2005 were due to H3N2 virus, and 93.5% during 2005-2006 were due to H1N1 virus. During 2004-2005, infants <1 year of age had the highest rate of hospitalization for influenza A (103.8 cases per 10,000 population), whereas children 1 year of age had the highest rate of hospitalization during the other 2 seasons (95.5 and 54.6 cases per 10,000 population during 2003-2004 and 2005-2006, respectively). A protection rate of 25%, presumably attributable to maternal antibodies, was seen in infants <1 year of age who were hospitalized during 2003-2004 with infection due to an H3N2 virus that had been in circulation. The hospitalization rates for influenza B were highest among children 2-4 years of age. Conclusions. This population-based study of hospitalizations due to virologically confirmed influenza demonstrated a very high burden of disease among young children in Hong Kong. The morbidity varied with virus type, subtype, and antigenic variants. © 2009 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio
Pseudo-Killing Spinors, Pseudo-supersymmetric p-branes, Bubbling and Less-bubbling AdS Spaces
We consider Einstein gravity coupled to an n-form field strength in D
dimensions. Such a theory cannot be supersymmetrized in general, we
nevertheless propose a pseudo-Killing spinor equation and show that the AdS X
Sphere vacua have the maximum number of pseudo-Killing spinors, and hence are
fully pseudo-supersymmetric. We show that extremal p-branes and their
intersecting configurations preserve fractions of the pseudo-supersymmetry. We
study the integrability condition for general (D,n) and obtain the additional
constraints that are required so that the existence of the pseudo-Killing
spinors implies the Einstein equations of motion. We obtain new
pseudo-supersymmetric bubbling AdS_5 X S^5 spaces that are supported by a
non-self-dual 5-form. This demonstrates that non-supersymmegtric conformal
field theories may also have bubbling states of arbitrary droplets of free
fermions in the phase space. We also obtain an example of less-bubbling AdS
geometry in D=8, whose bubbling effects are severely restricted by the
additional constraint arising from the integrability condition.Comment: typos corrected, extra comments and references added, version
appeared in JHE
- …