On dynamical tunneling and classical resonances

This work establishes a firm relationship between classical nonlinear resonances and the phenomenon of dynamical tunneling. It is shown that the classical phase space with its hierarchy of resonance islands completely characterizes dynamical tunneling and explicit forms of the dynamical barriers can be obtained only by identifying the key resonances. Relationship between the phase space viewpoint and the quantum mechanical superexchange approach is discussed in near-integrable and mixed regular-chaotic situations. For near-integrable systems with sufficient anharmonicity the effect of multiple resonances {\it i.e.,} resonance-assisted tunneling can be incorporated approximately. It is also argued that the, presumed, relation of avoided crossings to nonlinear resonances does not have to be invoked in order to understand dynamical tunneling. For molecules with low density of states the resonance-assisted mechanism is expected to be dominant.Comment: Completely rewritten and expanded version of a previous submission physics/0410033. 14 pages and 10 figure

Bio-signals compression using auto-encoder

Latest developments in wearable devices permits un-damageable and cheapest way for gathering of medical data such as bio-signals like ECG, Respiration, Blood pressure etc. Gathering and analysis of various biomarkers are considered to provide anticipatory healthcare through customized applications for medical purpose. Wearable devices will rely on size, resources and battery capacity; we need a novel algorithm to robustly control memory and the energy of the device. The rapid growth of the technology has led to numerous auto encoders that guarantee the results by extracting feature selection from time and frequency domain in an efficient way. The main aim is to train the hidden layer to reconstruct the data similar to that of input. In the previous works, to accomplish the compression all features were needed but in our proposed framework bio-signals compression using auto-encoder (BCAE) will perform task by taking only important features and compress it. By doing this it can reduce power consumption at the source end and hence increases battery life. The performance of the result comparison is done for the 3 parameters compression ratio, reconstruction error and power consumption. Our proposed work outperforms with respect to the SURF method

Silver lead borate glasses doped with europium ions for phosphors applications

Europium (Eu3+) doped silver lead borate glasses with the composition of xEu2O3�(1 � x)Ag2 O�29PbO�70B2O3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol) have been successfully prepared by conventional melt quenching method. Thermal, structural and luminescence properties have been studied using thermograms, transmittance, excitation and emission spectra. From the differential scanning calorimetry studies, the glass transition temperatures (Tg) have been investigated and their values are ranging from 449 to 458�C. The investigation of Fourier transformer infrared spectra shows the presence of boron atoms in both BO3 and BO4 units in the glass network. In addition, it was found that new structural groups were present, such as boroxyl rings, pyro and dipenta-borate. Photoluminescence spectroscopy was used to examine down conversion emission under 394 nm excitation, which exhibits five emission bands centred at 577, 590, 612, 650 and 697 nm corresponding to 5D0�7F0, 5D0�7F1, 5D0�7F2, 5D0�7F3 and 5D0�7F4 transitions of Eu3+ ions, respectively. The Commission International de I�Eclairage France 1931 chromaticity coordinates estimated from the emission spectra; it was shown that a 0.5 mol Eu2O3 doped glass is quite suitable for efficient red phosphors application. © Indian Academy of Sciences

Europium-doped boro-bismuth-tellurite glasses for multicolor phosphor applications

The glass system (50–x)B2O3–30Bi2O3–20TeO2–xEu2O3 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0 mol%) having been prepared using the conventional melt quenching method, is investigated in terms of physical, optical, and luminescence properties. The density of these glasses is measured and the corresponding molar volume is also calculated. The (αhν)1/n versus hν graph was plotted and it is well fitted to both direct (n = 1/2) and indirect (n = 2) band gaps. The direct and indirect band gap values range from 2.57 to 2.94 eV and 1.74 to 2.58 eV, respectively. The Urbach energy of the glass system was calculated to have values ranging from 0.29 to 0.62 eV. Yellow, orange, and red emissions have been observed through photoluminescence (PL) spectroscopy excited at 464 nm and the obtained multicolor emissions have been demonstrated according to the Commission International de l’Eclairage de France 1931 standards. The results of PL studies indicated the possibility towards the development of multicolor phosphor applications

Influence of europium (Eu3+) ions on the optical properties of silver lead borate glasses

The influence of europium (Eu3+) ions on the optical properties of silver lead borate glasses of the xEu2O3–(1 – x)Ag2O–29PbO–70B2O3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol%) glass system prepared by theconventional melt quenching technique and their physical and optical properties were investigated. The UV absorption spectra were recorded at room temperature in the wavelength range of 200–600 nm. From the absorption edge data, it is found that both the direct and indirect transitions and their values are ranging from 3.19 to 3.54 and 2.50 to 3.07 eV, respectively. The Urbach energy values for these glasses were found to be in the range of 0.39–0.52 eV. The refractive indices have also been evaluated with respect to different molar concentrations of Eu2O3 and their calculated values are ranging from 1.598 to 1.654

Understanding highly excited states via parametric variations

Highly excited vibrational states of an isolated molecule encode the vibrational energy flow pathways in the molecule. Recent studies have had spectacular success in understanding the nature of the excited states mainly due to the extensive studies of the classical phase space structures and their bifurcations. Such detailed classical-quantum correspondence studies are presently limited to two or quasi two dimensional systems. One of the main reasons for such a constraint has to do with the problem of visualization of relevant objects like surface of sections and Wigner or Husimi distributions associated with an eigenstate. This neccesiates various alternative techniques which are more algebraic than geometric in nature. In this work we introduce one such method based on parametric variation of the eigenvalues of a Hamiltonian. It is shown that the level velocities are correlated with the phase space nature of the corresponding eigenstates. A semiclassical expression for the level velocities of a single resonance Hamiltonian is derived which provides theoretical support for the correlation. We use the level velocities to dynamically assign the highly excited states of a model spectroscopic Hamiltonian in the mixed phase space regime. The effect of bifurcations on the level velocities is briefly discussed using a recently proposed spectroscopic Hamiltonian for the HCP molecule.Comment: 12 pages, 9 figures, submitted to J. Chem. Phy

An Investigation on the Influence of Modeling Approach and Load Pattern on Seismic Performance of RC Structures

Non-linear Static Analysis serves as a suitable measure to evaluate the performance of a structural system. The careful selection of modelling approach and the load pattern is critical to arrive at an adequate performance evaluation. The present study seeks to evaluate and compare the response of an existing eight story reinforced concrete structure, through the application of different modeling approaches and load patterns prescribed by FEMA 356. The results indicates that, with extreme clarity, that in all cases, the shape of the lateral load distribution is what the response of the buildings is finely accustomed to. This is especially true when different patterns of load are considered. It can also be observed that there is a very small difference between various load patterns

Analyzing intramolecular vibrational energy redistribution via the overlap intensity-level velocity correlator

Numerous experimental and theoretical studies have established that intramolecular vibrational energy redistribution (IVR) in isolated molecules has a heirarchical tier structure. The tier structure implies strong correlations between the energy level motions of a quantum system and its intensity-weighted spectrum. A measure, which explicitly accounts for this correaltion, was first introduced by one of us as a sensitive probe of phase space localization. It correlates eigenlevel velocities with the overlap intensities between the eigenstates and some localized state of interest. A semiclassical theory for the correlation is developed for systems that are classically integrable and complements earlier work focusing exclusively on the chaotic case. Application to a model two dimensional effective spectroscopic Hamiltonian shows that the correlation measure can provide information about the terms in the molecular Hamiltonian which play an important role in an energy range of interest and the character of the dynamics. Moreover, the correlation function is capable of highlighting relevant phase space structures including the local resonance features associated with a specific bright state. In addition to being ideally suited for multidimensional systems with a large density of states, the measure can also be used to gain insights into the phase space transport and localization. It is argued that the overlap intensity-level velocity correlation function provides a novel way of studying vibrational energy redistribution in isolated molecules. The correlation function is ideally suited to analyzing the parametric spectra of molecules in external fields.Comment: 16 pages, 13 figures (low resolution