FZZ Algebra

The duality between the Sine-Liouville conformal field theory and the two dimensional black hole is revisited by considering the two possible Sine-Liouville dressings together. We show that this choice is consistent with the structure of correlation functions, and that the OPE of the two dressings yields the black hole deformation operator. As an application of this approach, we investigate the role of higher winding perturbations in the context of c=1 strings, where we argue that they are related to higher-spin discrete states that generalize the 2d black hole operator.Comment: 23 pages, JHEP style. v2: small modifications to better clarify some of the argument

Hard-gapped Holographic Superconductors

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.Comment: 9 pages, latex, 6 figure

Embedded Network Test-Bed for Validating Real-Time Control Algorithms to Ensure Optimal Time Domain Performance

The paper presents a Stateflow based network test-bed to validate real-time optimal control algorithms. Genetic Algorithm (GA) based time domain performance index minimization is attempted for tuning of PI controller to handle a balanced lag and delay type First Order Plus Time Delay (FOPTD) process over network. The tuning performance is validated on a real-time communication network with artificially simulated stochastic delay, packet loss and out-of order packets characterizing the network.Comment: 6 pages, 12 figure

Comparative Studies on Decentralized Multiloop PID Controller Design Using Evolutionary Algorithms

Decentralized PID controllers have been designed in this paper for simultaneous tracking of individual process variables in multivariable systems under step reference input. The controller design framework takes into account the minimization of a weighted sum of Integral of Time multiplied Squared Error (ITSE) and Integral of Squared Controller Output (ISCO) so as to balance the overall tracking errors for the process variables and required variation in the corresponding manipulated variables. Decentralized PID gains are tuned using three popular Evolutionary Algorithms (EAs) viz. Genetic Algorithm (GA), Evolutionary Strategy (ES) and Cultural Algorithm (CA). Credible simulation comparisons have been reported for four benchmark 2x2 multivariable processes.Comment: 6 pages, 9 figure

Ovarian tumors in patients aged upto 20 years: a longitudinal study conducted in a tertiary care centre, West Bengal, India

Background: International treatment guidelines dedicated to children and adolescents are not yet established, hence need for such studies like ours is required to throw light on demographic variations of ovarian tumors and developing specific guidelines for their management.Methods: It was a descriptive longitudinal study undertaken in the Department of Obstetrics and Gynaecology from February 2018 to July 2019. According to prevalence in our setup, 50 cases of adolescent girls and children were taken for study and subjected to thorough clinical assessment and investigations. After proper diagnosis, surgery was performed in all cases and depending upon histopathology and cytology, adjuvant chemotherapy was given in selected cases. Patients were followed up till 6 months after discharge.Results: The most common symptom was found to be abdominal pain (42%), most common sign abdominal mass (38%). Out of 50 cases, 12% were found to be malignant, all of germ cell origin. Epithelial tumors were found to be the most common ovarian tumors (52%) up to 20 years of age, out of which benign tumors had 48% epithelial origin. However, up to 10 years of age, germ cell tumors were found to be the most common (75%). Only 1 malignant case expired, belonging to mixed germ cell variety of advanced stage.Conclusions: Ovarian neoplasm is highly challenging, especially in adolescents and children due to the need for fertility preservation. Early detection, optimal therapy and intense follow up with psychological support to patients and families are the mainstay of treatment.

Dissolved deconfinement: Phase Structure of large N gauge theories with fundamental matter

A class of large N SU(N) gauge theories on a compact manifold S^3 X R (with possible inclusion of adjoint matter) is known to show first order deconfinement transition at the deconfinement temperature. This includes the familiar example of pure YM theory and N=4 SYM theory. Here we study the effect of introduction of N_f fundamental matter fields in the phase diagram of the above mentioned gauge theories at small coupling and in the limit of large N and finite N_f/N. We find some interesting features like the termination of the line of first order deconfinement phase transition at a critical point as the ratio N_f/N is increased and absence of deconfinement transition thereafter (there is only a smooth crossover). This result may have some implication for QCD, which unlike a pure gauge theory does not show a first order deconfinement transition and only displays a smooth crossover at the transition temperature.Comment: 22 pages, 19 figures, revtex4. Updated formattin

Holographic Non-Fermi Liquid in a Background Magnetic Field

We study the effects of a non-zero magnetic field on a class of 2+1 dim non-Fermi liquids, recently found in 0903.2477 by considering properties of a fermionic probe in an extremal AdS^4 black hole background. Introducing a similar fermionic probe in a dyonic AdS^4 black hole geometry, we find that the effect of a magnetic field could be incorporated in a rescaling of the probe fermion's charge. From this simple fact, we observe interesting effects like gradual disappearance of the Fermi surface and quasi particle peaks at large magnetic fields and changes in other properties of the system. We also find Landau level like structures and oscillatory phenomena similar to the de Haas-van Alphen effect.Comment: 20 pages, latex, 6 figure

Noncritical-topological correspondence: disc amplitudes and noncompact branes

We examine the duality between type 0 noncritical strings and topological B-model strings, with special emphasis on the flux dependence. The former theory is known to exhibit holomorphic factorisation upto a subtle flux-dependent disc term. We give a precise definition of the B-model dual and propose that it includes both compact and noncompact B-branes. The former give the factorised part of the free energy, while the latter violate holomorphic factorisation and contribute the desired disc term. These observations are generalised to rational radii, for which we derive a nonperturbatively exact result. We also show that our picture extends to a proposed alternative topological-anti-topological picture of the correspondence for type 0 strings

Comments on Non-Fermi Liquids in the Presence of a Condensate

We study the effects of a scalar condensate on a class of 2+1 dimensional non- Fermi liquids by introducing fermionic probes in the corresponding asymptotically AdS4 black hole backgrounds. For the range of parameters and couplings we consider we find gapless fermionic excitations whose properties are model-dependent.Comment: 13 page