Determination of maximal Gaussian entanglement achievable by feedback-controlled dynamics

We determine a general upper bound for the steady-state entanglement achievable by continuous feedback for systems of any number of bosonic degrees of freedom. We apply such a bound to the specific case of parametric interactions - the most common practical way to generate entanglement in quantum optics - and single out optimal feedback strategies that achieve the maximal entanglement. We also consider the case of feedback schemes entirely restricted to local operations and compare their performance to the optimal, generally nonlocal, schemes.Comment: 4 pages. Published versio

Intensity and polarization line profiles in a semi-infinite Rayleigh-scattering planetary atmosphere. III. Variation of polarization profiles and the Stokes parameter Q over the disk

The variation of the polarization profiles, the Stokes parameters Q and U, and the angle defining the plane of polarization along the intensity equator and along the mirror meridian, on which μ = μ0, in a Rayleigh scattering atmosphere is studied. It is found that these variations are more complex than thought hitherto, particularly at large phase angles

A reconsideration of the effective depth of line formation in planetary atmospheres

A new definition of the effective depth of line formation is given which incorporates its dependence on the angle of emergence as well as on the position within the line. Solution obtained for isotropic scattering in the third approximation of discrete ordinates explains: (i) Variation of equivalent widths over the disc; (ii) Inverse dependence of this variation on line strength; and (iii) The phase effect for relative equivalent widths

Intensity and Polarization line profiles in a semi-infinite Rayleigh-scattering planetary atmosphere. II. Variations of equivalent width over the disk

The study of the variation of equivalent width in a Rayleighscattering planetary atmosphere along the intensity equator and along the mirror meridian on which μ =μ0 shows that the equivalent widths decrease monotonically towards the poles, the limb and the terminator with the following characteristics: (i) the weakest lines exhibit the maximum change; (ii) the Ier component shows more change than the Iel component; (iii) the decrease towards the limb or the terminator is not as sharp as that towards the poles; (iv)Iel component shows more decrease towards the limb while Ier component shows more decrease towards the terminator; and (v) the relation W (μ,φ;μ0,φ0)= W (μ0,φ0;μ,φ) holds for the total intensity. These results are qualitatively in agreement with the observations of absorption bands in the spectra of Venus, Jupiter and Saturn

No Tension Approach to Define Failure Phenomena for Rockfill Dam Subjected to Earthquake Loading

It has been observed that actual behavior of Rockfill dams during earthquake is much different than that obtained by elastic analysis. No tension approach has thus been developed to overcome the shortfalls of elastic analysis. Using no tension approach redistribution of stresses are obtained which help in defining the failure pattern of the dam\u27 subjected to a given seismic acceleration or in other words the failure acceleration is obtained for a given dam subjected to earthquake forces. Various dam models having different upstream and downstream slopes are analyzed using finite element technique. The input earthquake motion has been considered as an equivalent static force. Anisotropy of the rockfill material has been considered. The failure acceleration level for various dam models having different upstream and downstream slopes are thus evaluated. The results are compared with those obtained experimentally and show a good agreement

Positive definite functions and operator inequalities

We construct several examples of positive definite functions, and use the positive definite matrices arising from them to derive several inequalities for norms of operators

Tobacco and health: What can the medical profession do?

Tobacco consumption, that leads to three million deaths every year of which about one million occur in developing countries is a social evil(1). Tobacco smoke is a complex mixture of as many as 4700 individual constituents including carcinogens, irritants, ciliotoxic substances and poisonous gases. There is no dearth of information about the health hazards to smokers. it has been implicated as a major risk factor in a variety of chronic diseases including cardiac, cerebrovascular, malignant, respiratory and other diseases (2), Most of the smoking related lung diseases (e.g. chronic obstructive lung disease and lung carcinoma) are dose dependent. it is often the cumulative dose of smoking which determines the risk. Parameters like pack-year (PY) have been used to express exposure to tobacco smoke. One PY implies one packet of cigarettes (or 20 gms. tobacco) smoked each day over a course of one year (3). In India the number of cigarettes and bidis per packet is quite variable. A standard packet of cigarette and bidis per packet is quite variable

Entropic uncertainty relations and entanglement

We discuss the relationship between entropic uncertainty relations and entanglement. We present two methods for deriving separability criteria in terms of entropic uncertainty relations. Especially we show how any entropic uncertainty relation on one part of the system results in a separability condition on the composite system. We investigate the resulting criteria using the Tsallis entropy for two and three qubits.Comment: 8 pages, 3 figures, v2: small change

Pathogenesis of dystonia: is it of cerebellar or basal ganglia origin?

Dystonia is a disorder of motor programmes controlling semiautomatic movements or postures, with clinical features such as sensory trick, which suggests sensorimotor mismatch as the basis. Dystonia was originally classified as a basal ganglia disease. It is now regarded as a 'network' disorder including the cerebellum, but the exact pathogenesis being unknown. Rare autopsy studies have found pathology both in the striatum and the cerebellum, and functional disorganisation was reported in the somatosensory cortex in patients. Recent animal studies showed physiologically tight disynaptic connections between the cerebellum and the striatum. We review clinical evidence in light of this new functional interaction between the cerebellum and basal ganglia, and put forward a hypothesis that dystonia is a basal ganglia disorder that can be induced by aberrant afferent inputs from the cerebellum

Pass-transistor very large scale integration

Logic elements are provided that permit reductions in layout size and avoidance of hazards. Such logic elements may be included in libraries of logic cells. A logical function to be implemented by the logic element is decomposed about logical variables to identify factors corresponding to combinations of the logical variables and their complements. A pass transistor network is provided for implementing the pass network function in accordance with this decomposition. The pass transistor network includes ordered arrangements of pass transistors that correspond to the combinations of variables and complements resulting from the logical decomposition. The logic elements may act as selection circuits and be integrated with memory and buffer elements