117480588
Weak Gravity Conjecture, Central Charges and $\eta/s$
We correlate the weak gravity conjecture (WGC), the KSS conjecture with chemical potential at extremality and the central charges by going through a particular example in five dimensional AdS spacetime with two unknown coefficients $c_1, c_2$, assuming WGC exists in AdS spacetime. The result that follows from this example suggests that WGC makes the KSS conjecture to hold in the extremal limit but only when one of the coefficient vanishes ($c_1=0, c_2\neq 0$ or $c_2=0, c_1\neq 0$) and when both the coefficients are non zero it can respect and/or violate the KSS conjecture depending on the choice to $c_1$ at extremality, even though $\eta/s$ do not depend on $c_1$ at extremality. Moreover, WGC is not fully compatible with the calculation of central charges even though the bounds on coefficient $c_1$ that follows from demanding WGC stays within the bounds that central charges predict. As usual, the KSS conjecture is violated, of course, in the non-extremal limit.
15867017
NONSINGULAR COSMOLOGIES FROM BRANES
We analyze possible cosmological scenarios on a brane where the brane acts as a dynamical boundary of various black holes with anti-de Sitter or de Sitter asymptotic. In many cases, the brane is found to describe the completely nonsingular universe. In some cases, quantum gravity era of the brane-universe can also be avoided by properly tuning bulk parameters. We further discuss the creation of a brane-universe by studying its wave function. This is done by employing Wheeler–De Witt equation in the mini superspace formalism.
14651966
Supersymmetric and nonsupersymmetric perturbations to KT
We studied the supersymmetric and non-supersymmetric perturbations to cascading gauge theory. In particular we use KT background and the back reaction of the generic linearized perturbation make the dilaton to run and the $T^{(1,1)}$ gets squashed which in turn make the supersymmetry to be broken. But if we make a special linearized perturbation in such way that the $T^{(1,1)}$ is not squashed then the corresponding perturbation preserve supersymmetry.
118477119
eta/s at finite coupling
We compute the ratio of the coefficient of shear viscosity to entropy density at finite coupling and at zero chemical potential using holographic duality, up to ten derivative terms in the low energy effective five-dimensional action, of a specific kind, which may or may not be connected to the supersymmetric completion of type IIB theory. The result suggests that this ratio can be positive only for the 8th derivative term even with the form of that term in the action as C{sup ij}{sub kl}C{sup kl}{sub mn}C{sup mn}{sub rs}C{sup rs}{sub ij}, where C is the Weyl tensor.
13048896
A new Ricci-flat geometry
Abstract We are proposing a new Ricci-flat metric constructed from an infinite family of Sasaki–Einstein, Y ( p , q ) , geometries. This geometry contains a free parameter s and in the s → 0 limit we get back the usual CY. When this geometry is probed both by a stack of D3 and fractional D3 branes then the corresponding supergravity solution is found which is a warped product of this new 6-dimensional geometry and the flat R 3 , 1 . This solution in the specific limit as mentioned above reproduces the solution found in hep-th/0412193 . The integrated five-form field strength over S 2 × S 3 goes logarithmically but the argument of Log function is different than has been found before.
119087207
SOLUTION TO WORLDVOLUME ACTION OF D3 BRANE IN pp-WAVE BACKGROUND
We find nonsupersymmetric and supersymmetric solutions of D3 brane configuration in the background of pp-wave obtained as a Penrose limit of AdS5 × S5.
122669506
High voltage characteristic of large area cathode pad chambers for muon spectrometer of ALICE
AbstractLarge area Cathode Pad Chambers (CPC) with inner and outer radii of 23.7 cm and 117 cm respectively have been fabricated and tested for 2nd Tracking station of Muon Spectrometer of ALICE.The active area of this detector has a radiation length of less than 2 % and the frames are fabricated with Peek GF-30. The anode wire plane consists of 474 anode wires of which 53 % have lengths greater than 1 meter. The separation between the wire plane and the grounded cathode plane is 2.5 mm. The high voltage behaviour of the chamber have been tested under two situations.
With no support below the wires to reduce sagging of long wires.With a G10 strip-support whose dimension is 950 mm × 2 mm × 2.4 mm.
 The High Voltage (HV) tests show that a better stability is achieved when the strip support is implemented. Therefore this solution has been adopted for operation in ALICE.