Antiferromagnetism in a bosonic mixture of rubidium (87^{87}Rb) and potassium (41^{41}K)

We simulate the experimental possibility of observing the antiferromagnetic (AF) order in the bosonic mixtures of rubidium ($^{87}$Rb) and potassium ($^{41}$K) in a two-dimensional optical lattice in the presence of harmonic confinement. By tuning the interspecies interactions and the lattice heights we have found the ground states, within the mean-field approximation, that interpolate from the phase separation to the AF order. For a moderate lattice height the coexistence of the Mott and AF phase is possible for the Rb atoms while the K atoms remain in the AF-superfluid phase. This observation may provide an experimental feasibility to hitherto unobserved AF order for $^{87}$Rb - $^{41}$K mixture.Comment: 4 pages, 4 figures, accepted for PRA rapid communicatio

Intermediate-Level Crossings of a First-Passage Path

We investigate some simple and surprising properties of a one-dimensional Brownian trajectory with diffusion coefficient $D$ that starts at the origin and reaches $X$ either: (i) at time $T$ or (ii) for the first time at time $T$. We determine the most likely location of the first-passage trajectory from $(0,0)$ to $(X,T)$ and its distribution at any intermediate time $t<T$. A first-passage path typically starts out by being repelled from its final location when $X^2/DT\ll 1$. We also determine the distribution of times when the trajectory first crosses and last crosses an arbitrary intermediate position $x<X$. The distribution of first-crossing times may be unimodal or bimodal, depending on whether $X^2/DT\ll 1$ or $X^2/DT\gg 1$. The form of the first-crossing probability in the bimodal regime is qualitatively similar to, but more singular than, the well-known arcsine law.Comment: 18 pages, 12 figures, IOP format; V2: various minor changes in response to referee comments. For publication in JSTA

Super Quantum Discord with Weak Measurements

Weak measurements cause small change to quantum states, thereby opening up the possibility of new ways of manipulating and controlling quantum systems. We ask, can weak measurements reveal more quantum correlation in a composite quantum state? We prove that the weak measurement induced quantum discord, called as the "super quantum discord", is always larger than the quantum discord captured by the strong measurement. Moreover, we prove the monotonicity of the super quantum discord as a function of the measurement strength. We find that unlike the normal quantum discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. Our result shows that the notion of quantum correlation is not only observer dependent but also depends on how weakly one perturbs the composite system.Comment: Latex, 5 pages, 2 Figs, Monotonicity of the super discord with the measurement strength is included. Application to the entropic uncertainty relation will be reported separatel

Use of calcium carbide for artificial ripening of fruits : its application and hazards

A review of different articles related to artificial ripening was done. Focus was given on the hazards and applications of calcium carbide for artificial ripening, being a very common practice in Nepalese Market. Litterateurs showed many hazardous aspects of carbide use and also standard procedures of safety handling aspects. But being banned by regulation, due to its hazardous aspects and lack of proper handling methods among users, it was concluded that the use of calcium carbide is to be strictly monitored and controlled

Asymmetry and coherence weight of quantum states

The asymmetry of quantum states is an important resource in quantum information processing tasks such as quantum metrology and quantum communication. In this paper, we introduce the notion of $asymmetry~weight$ --- an operationally motivated asymmetry quantifier in the resource theory of asymmetry. We study the convexity and monotonicity properties of asymmetry weight and focus on its interplay with the corresponding semidefinite programming (SDP) forms along with its connection to other asymmetry measures. Since the SDP form of asymmetry weight is closely related to asymmetry witnesses, we find that the asymmetry weight can be regarded as a (state-dependent) asymmetry witness. Moreover, some specific entanglement witnesses can be viewed as a special case of an asymmetry witness --- which indicates a potential connection between asymmetry and entanglement. We also provide an operationally meaningful coherence measure, which we term $coherence~weight$, and investigate its relationship to other coherence measures like the robustness of coherence and the $l_1$ norm of coherence. In particular, we show that for Werner states in any dimension $d$, all three coherence quantifiers, namely, the coherence weight, the robustness of coherence, and the $l_1$ norm of coherence, are equal and are given by a single letter formula.Comment: 11 pages, 4 figures. v2; close to published version. Matlab code to calculate coherence weight included in the sourc

Bangladesh 2020 - An Analysis of Growth Prospect and External Sector Behaviour

External factors such as export, import, remittances and foreign aid have always played important roles to Bangladeshs economy, though the relative importance of various external factors has changed over time. This study has analysed the trend, structure and changing features of the external sector of Bangladesh. Based on the past performance and changes in the global economy, the study has projected the growth prospect and likely behaviour of Bangladeshs external sector under three scenarios : (i) optimistic scenario (8% GDP growth per annum), (ii) business as usual scenario (6% GDP growth per annum), and (iii) base case scenario (4% GDP growth per annum). Under these three scenarios, the study has projected the level of total GDP and per capita GDP of Bangladesh till FY2020. Projections are made about the required level of exports, imports, remittances, foreign aid and foreign investment to attain a consistent GDP growth at the rate of 4%, 6% and 8% up to the year 2020. The paper has also put forward the implications of the findings for policies related to the external sector of Bangladesh. The paper suggests that Bangladesh needs a steady growth based on foreign investment, service income and trade. The report adds that future growth of Bangladesh will depend on promoting export, sustaining remittances, and triggering export. Bangladesh will require a breakthrough in the performance of the external sector. According to the report, the key to the breakthrough lies in effective integration of Bangladeshs economy with the global economy which will ultimately depend on the ability of political leadership to undertake necessary policy reforms and institution building measures.