Bose-Einstein condensates with attractive 1/r interaction: The case of self-trapping

Amplifying on a proposal by O'Dell et al. for the realization of Bose-Einstein condensates of neutral atoms with attractive $1/r$ interaction, we point out that the instance of self-trapping of the condensate, without external trap potential, is physically best understood by introducing appropriate "atomic" units. This reveals a remarkable scaling property: the physics of the condensate depends only on the two parameters $N^2 a/a_u$ and $\gamma/N^2$, where $N$ is the particle number, $a$ the scattering length, $a_u$ the "Bohr" radius and $\gamma$ the trap frequency in atomic units. We calculate accurate numerical results for self-trapping wave functions and potentials, for energies, sizes and peak densities, and compare with previous variational results. As a novel feature we point out the existence of a second solution of the extended Gross-Pitaevskii equation for negative scattering lengths, with and without trapping potential, which is born together with the ground state in a tangent bifurcation. This indicates the existence of an unstable collectively excited state of the condensate for negative scattering lengths.Comment: 7 pages, 7 figures, to appear in Phys. Rev.

Secure Cloud Computing Based On Mobile Agents

In this paper, we provide protection to the service requested to the cloud from user. Cloud computing is a examine sloping system that launch services to the client at low cost. According to various researches user verification is the most significant security concern and demanding issue in cloud-based environment. As cloud computing provides different advantages it also brings some of the concern about the security and privacy of information. Cloud computing requests to concentrate on three main security issues : privacy, reliability and accessibility. In this paper, we propose a new approach that provides confidentiality for the services request by the user by using mobile agents for communication between user and cloud layer; we provide security at each layer in cloud computing with Kerberos. We provide security to service which will be request to the cloud with authentication server and TGS system. DOI: 10.17762/ijritcc2321-8169.150318

Anomalous Thermoelectric power of over-doped Bi2Sr2CaCu2O8 superconductor

Temperature dependence of thermoelectric power S(T) of three differently processed Bi2Sr2CaCu2O8 (Bi2212) samples, viz. as-processed melt quenched (Bi2212-MQ), 6000C N2-annealed (Bi2212-N2) and 6000C O2-annealed (Bi2212-O2) is reported here. All the samples possess single-phase character and their superconducting transition temperatures (TcR=0) are 85 K, 90 K and 72 K respectively for Bi2212-MQ, Bi2212-N2 and Bi2212-O2. While Bi2212-MQ and Bi2212-N2 samples are in near optimum doping regime, Bi2212-O2 is an over-doped sample. TcS=0 values obtained through S(T) data are also in line with those deduced from the temperature dependence of resistance and DC magnetization. Interestingly, S(T) behaviour of the optimally-doped Bi2212-MQ and Bi2212-N2 samples is seen to be positive in whole temperature range, it is found negative for the over-doped Bi2212-O2 sample above TcS=0. These results have been seen in the light of the recent band structure calculations and the ensuing split Fermi surface as determined by angle-resolved photoelectron spectroscopy (ARPES).Comment: 11 Pages Text + Figs: comments welcome ([email protected]

Design and Analysis of Double layer Microstrip patch antenna

Volume 2 Issue 1 (January 2014

Development of an Unequal Speed Co-axial Split-Rotor Thresher for Riceit

During high moisture paddy threshing, the separation losses are generally large. However,while attempting to increase cropping intensity, it is often necessary to handle the moist paddy for threshing. Furthermore, in absence of adequate sunshine hours in wet season, crop can’t be dried to a desired moisture level before threshing. Keeping these requirements in mind, a co-axial split-rotor thresher was designed for threshing high moisture paddy. This paper describes design and testing of a stationary thresher with an unequal speed co-axial split-rotor for rice in Thailand. First rotor serves mainly the threshing operation, whereas, rotating at relatively higher speed, the second rotor does mainly the separation of rice grains from husk. Faster rotation of second rotor increases separation performance by increasing centrifugal force. Optimum speed for threshing rotor was considered to be 25 m/s (600 rpm with 0.8 m diameter threshing rotor) and a speed for separation rotor was evaluated. For better grain separation, speed of 30.2 m/s (720 rpm with 0.8 m separation rotor) was found optimum. With the material feeding rate of 0.6-1.8 kg/s, the developed co-axial split-rotor thresher reduced the separation losses to 0.7-1.3% at the separation rotor speed range of 27.4-33.5 m/s. By increasing this speed above 33.5 m/s (800 rpm) the grain damage was increased

Study of Microstrip filters

Volume 2 Issue 1 (January 2014

Service Recommendation System using Social User’s Rating Behaviors

The research communities of information retrieval, machine learning and data mining are recently started to paying attention towards Service recommendation systems. Traditional service recommendation algorithms are often based on batch machine learning methods which are having certain critical limitations, e.g., mostly systems are so costly also new user needs to pay the certain cost for new login, can’t capture the changes of user preferences over time. So that to overcome from that problem it is important to make service recommendation system more flexible for real world online applications where data arrives sequentially and user preferences may change randomly and dynamically. This system present a new website of online social recommendation on the basis of online graph regularized user preference learning (OGRPL), which incorporates both collaborative user-services relationship as well as service content features into an unified preference learning process. Also provide aggregated services in only one application (social networking) which increases user’s interest towards the services. This system also provides security about subscribed services as well as documents/photos on online social network application. This system will utilizes services like Education, adventure, Home Services, Hotels & Travel, Restaurants and Shopping

Transverse Tau Polarization in Decays of the Top and Bottom Quarks in the Weinberg Model of CP Non-conservation

We show that the transverse polarization asymmetry of the $\tau$-lepton in the decay $t\rightarrow b \tau \nu$ is extremely sensitive to CP violating phases arising from the charged Higgs exchange in the Weinberg model of CP non-conservation. Qualitatively, the polarization asymmetries are enhanced over rate or energy asymmetries by a factor of $\approx {m_t\over m_\tau}\approx O(100)$. Thus for optimal values of the parameters the method requires $\approx 10^4$ top pairs to be observable rather than $10^7$ needed for rate or energy asymmetries. We also examine $\tau$ polarization in b decays via $b \rightarrow c \nu \tau$ and find that it can also be very effective in constraining the CP violation parameters of the extended Higgs sector.Comment: 11,1 figure, SLAC-PUB-608

Extended Skyrme interaction (I): spin fluctuations in dense matter

Most of the Skyrme interactions are known to predict spin or isospin instabilities beyond the saturation density of nuclear matter which contradict predictions based on realistic interactions. A modification of the standard Skyrme interaction is proposed so that the ferromagnetic instability is removed. The new terms are density dependent and modify only the spin p-h interaction in the case of spin-saturated system. Consequences for the nuclear response function and neutrino mean free path are shown. The overall effect of the RPA correlations makes dense matter more transparent for neutrino propagation by a factor of 2 to 10 depending of the density.Comment: 6 pages, 5 Figs., 2 Tab