A stable Algebraic Spin Liquid in a Hubbard model

We show the existence of a stable Algebraic Spin Liquid (ASL) phase in a Hubbard model defined on a honeycomb lattice with spin-dependent hopping that breaks time-reversal symmetry. The effective spin model is the Kitaev model for large on-site repulsion. The gaplessness of the emergent Majorana fermions is protected by the time reversal (TR) invariance of this model. We prove that the effective spin model is TR invariant in the entire Mott phase thus ensuring the stability of the ASL. The model can be physically realized in cold atom systems and we propose experimental signals of the ASL.Comment: Published in PR

Design of Simulator to Evaluate Performance Parameters of Scheduling Clouds in Virtual Machine Environment

Cloud computing acts as a vision of infinite computing resources that are provided on-demand to the cloud users as needed and are billed on pay as per usage basis Cloud computing employs the concept of virtualization that provides an opportunity to achieve business and IT objectives Scheduling is one of the most important challenges that a cloud computing environment faces Scheduling process determines the order of execution of jobs and the virtual machine to which job is assigned to execute so as to improve the performance and quality of service and at the same time resources are utilized effectively An attempt has been made in this paper to develop a simulator to schedule a job on allocated virtual machine so as to make efficient resource utilization In the proposed work scheduling is done on the basis of availability of allocated virtual machine providing equal capabilities We assumed that arrival of jobs in a cloud and their execution on a virtual machine is exponentially distributed For analysing the proposed algorithm the performance parameters of scheduling clouds are evaluated in Virtual Machine Environmen

Quantitative variations in ovarian follicles of female Sprague Dawley rats after exposure to low dose gamma radiation

In the present experiment, an attempt was made to assess the genetic risk of low dose radiations in mammals. For this purpose female Sprague Dawley rats, 11-12 weeks old, were irradiated with whole body Co 60 gamma rays in three fractionated doses of 0.10 Gy (cumulative dose 0.30 Gy) given at an interval of one month at two different dose-rates (0.00368 Gy/min. and 0.0589 Gy/min.). Ovaries were studied for quantitative evaluation of follicles at 1, 4, 12, 28 and 52 weeks after last fractionated exposure. Quantitation revealed lower number of ovarian follicles in irradiated animals than in controls. The follicular number decreased with the advancement of time after last exposure (i.e. 2 months) and reached a peak level on 28 weeks. After that the recovery was evident but the number remained below 25% of total follicles even at 52 weeks autopsy interval, which indicated an irreversible damage in ovarian tissue. Primary follicles were found to be the most radiosensitive among the various types of follicles. The highest loss in these follicles was noted at 12 weeks after exposure with the high dose-rate, where only 10.61% of them were scored. Dose-rate exhibited an inverse relationship with the number of surviving follicles. At the higher dose-rate (0.0589 Gy / min.), depletion in the total follicular number was significantly higher than at the low dose-rate (0.00368 Gy/min.) used