Calculation of highly excited eigenstates of chaotic quantum systems

Computational methods for the calculation of a large number of eigenstates of coupled oscillator system are developed and discussed. These calculations have enabled us to identify and investigate properties of an infinite set of states sharply localized in configuration space in this system. Some of the results and their significance are discussed. Extensions to three-dimensional systems are also briefly considered.     

Spectral fluctuations and 1/f noise in the order-chaos transition regime

Level fluctuations in a quantum system have been used to characterize quantum chaos using random matrix models. Recently time series methods were used to relate the level fluctuations to the classical dynamics in the regular and chaotic limit. In this, we show that the spectrum of the system undergoing order to chaos transition displays a characteristic f(-gamma) noise and gamma is correlated with the classical chaos in the system. We demonstrate this using a smooth potential and a time-dependent system modeled by Gaussian and circular ensembles, respectively, of random matrix theory. We show the effect of short periodic orbits on these fluctuation measures.     

Some exact solutions in string cosmology

Some Bianchi-type string-cosmological models are presented here. The physical implications of the models are briefly discussed     

The deuterium effect on electrochemiluminescence efficiencies of anthracene and phenanthrene

The effect of deuteration on the electrochemiluminescence (ECL) efficiencies of the mixed systems containing anthracene or phenathrene has been examined using the single light pulse in the double potential programme. Deuteration of anthracene or phenanthrene decreases the ECL efficiencies by factors of 1·2–16·0. This decrease appears to arise from the quenching of the triplets by radical ions in solution. The quenching factors are estimated by using Marcus theory of electron transfer reactions.     

Quantum mechanics in discrete space and angular momentum

Recently we have studied quantum mechanics of bounded operators with a discrete spectrum. In particular, we derived an expression for the commutator[Q, P] of two bounded operators whose spectrum is discrete, and we showed that in the limit of a continuous spectrum the commutator becomes the standard one of Heisenberg. In this paper we show that the angular momentum operator and the phase operator satisfy the new commutation relation. We also briefly discuss the problem of the canonical phase operator conjugate to the number operator.     

An improved synthesis of enantiomerically pure RWJ 69442, a development candidate for the treatment of benign prostatic hyperplasia

This report describes an improved synthesis of enantiomerically pure (S)‐2‐[4‐(Dimethylamino)phenyl]‐2,3‐dihydro‐N‐[2‐hydroxy‐3‐[4‐[2‐(1‐methylethoxy)‐phenyl]‐1‐piperazinyl]propyl]‐1,3‐dioxo‐1H‐isoindole‐5‐carboxamide (RWJ 69442), a potent and selective α_la‐adrenergic receptor antagonist for the treatment of benign prostatic hyperplasia. The synthesis highlights less hazardous reagents, easier purification and higher enantiomeric purity. The N‐benzyl‐N—t‐butoxycarbonyl amine 6 could serve as an enantiomerically pure chiral building block for asymmetric synthesis.     

Combined effects of ceramic filler size and ethylene oxide length on the ionic transport properties of solid polymer electrolyte derivatives of PEGMEMA

In this work, the synthesis of a series of solid polymer electrolyte (SPE) derivatives of poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), homogenously dispersed with TiO₂ ceramic nano-filler, has been reported. The interactions between filler size and the length of the ethylene oxide (EO) polymer backbone are discussed, and transport properties such as ionic conductivity and cation transference number are determined. Results show that the improved performance of the SPE is due to an interaction between the ceramic filler and the entwining behavior of the PEGMEMA backbone. An optimal ceramic filler size and an appropriate length of EO have been suggested for the enhanced performance of SPE derivatives of PEGMEMA for a next-generation polymer battery.