On the disentangling process for two-mode squeezed state

A pure state decoheres into a mixed state as the system entangles with an environment which is initially in a pure state. However, it is not definite that the system becomes entangled with a confined environment with which it only ever interacts. We investigate the disentangling mechanism by considering the quantum correlation between a two-mode squeezed state and a thermal environment.

Many-body entanglement in decoherence processes

A pure state decoheres into a mixed state as it entangles with an environment. When an entangled two-mode system is embedded in a thermal environment, however, each mode may not be entangled with its environment by their simple linear interaction. We consider an exactly solvable model to study the dynamics of a total system, which is composed of an entangled two-mode system and a thermal environment. The Markovian interaction with the environment is concerned with an array of infinite number of beam splitters. It is shown that many-body entanglement of the system and the environment may play a crucial role in the process of disentangling the system.

Phase transition and decomposition temperatures, heat capacities and viscosities of pyridinium ionic liquids

Ionic liquids are organic salts with low melting points. Many of these compounds are liquid at room temperature in their pure state. Since they have negligible vapor pressure and would not contribute to air pollution, they are being intensively investigated for a variety of applications, including as solvents for reactions and separations, as non-volatile electrolytes, and as heat transfer fluids. We present melting temperatures, glass transition temperatures, decomposition temperatures, heat capacities, and viscosities for a large series of pyridinium-based ionic liquids. For comparison, we include data for several imidazolium and quaternary ammonium salts. Many of the compounds do not crystallize, but form glasses at temperatures between 188 K and 223 K. The thermal stability is largely determined by the coordinating ability of the anion, with ionic liquids made with the least coordinating anions, like bis(trifluoromethylsulfonyl)imide, having the best thermal stability. In particular, dimethylaminopyridinium bis(trifluoromethylsulfonyl)imide salts have some of the best thermal stabilities of any ionic liquid compounds investigated to date. Heat capacities increase approximately linearly with increasing molar mass, which corresponds with increasing numbers of translational, vibrational, and rotational modes. Viscosities generally increase with increasing number and length of alkyl substituents on the cation, with the pyridinium salts typically being slightly more viscous than the equivalent imidazolium compounds. (c) 2005 Elsevier Ltd. All rights reserved.

State power matters: power, the state and political struggle in the post-war American novel

This article is concerned with resituating the state at the centre of the analytical stage and, concomitantly, with drawing attention to the dangers of losing sight of the state as a locus of power. It seeks to uncover the relationship between two related lines of critical inquiry: Marxist and Foucauldian theories of the state; and the attempts by three postwar American novelist (Ken Kesey, William Burroughs and E.L. Doctorow) to determine the nature and extent of this power and to consider under what conditions political struggle might be possible. It argues that such a move is needed because recent critical analysis has been too preoccupied by corporeal micropolitics and global macropolitics, and that the postwar American novel can help us in this move because it is centrally concerned with the repressive potentiality of the US state. It maintains that the resuscitation of Marxist state theories in early 1970s and a debate between Poulantzas and Foucault is intriguingly foreshadowed and even critiqued by these novels. Consequently, it concludes that these novels constitute an unrecognized pre-history of what would become one of the key intellectual debates of the late twentieth century: an engagement between Marxist and post-structuralist conceptions of the power and resistance.

Two-wire thermocouples: A nonlinear state estimation approach to temperature reconstruction.

The problem of measuring high frequency variations in temperature is described, and the need for some form of reconstruction introduced. One method of reconstructing temperature measurements is to use the signals from two thermocouples of differing diameter. Two existing methods for processing such measurements and reconstructing the higher frequency components are described. These are compared to a novel reconstruction algorithm based on a nonlinear extended Kalman filter. The performance of this filter is found to compare favorably, in a number of ways, with the existing techniques, and it is suggested that such a technique would be viable for the online reconstruction of temperatures in real time.

Fundamentals of steady state, non-Newtonian rimming flow

Rimming flow on the inner surface of a horizontal rotating cylinder is investigated. Using a scale analysis, a theoretical description is obtained for steady-state non-Newtonian flow. Simple lubrication theory is applied since the Reynolds number is small and the liquid film is thin. Since the Deborah number is very small the flow is viscometric. The shear-thinning number, which characterizes the shear-thinning effect, may be small or large. A general constitutive law for this kind of flow requires only a single function relating shear stress and shear rate that corresponds to a generalized Newtonian liquid. For this case the run-off condition for rimming flow is derived. Provided the run-off condition is satisfied, the existence of a continuous steady-state solution is proved. The rheological models, which show Newtonian behavior at low shear rates with transition to power-law shear thinning at moderate shear rates, are considered. Numerical results are carried out for the Carreau and Ellis models, which exhibit Newtonian behavior near the free surface and power-law behavior near the wall of the rotating cylinder.