Emergence of Skyrme crystal in Gross-Neveu and 't Hooft models at finite density

We study two-dimensional, large $N$ field theoretic models (Gross-Neveu model, 't Hooft model) at finite baryon density near the chiral limit. The same mechanism which leads to massless baryons in these models induces a breakdown of translational invariance at any finite density. In the chiral limit baryonic matter is characterized by a spatially varying chiral angle with a wave number depending only on the density. For small bare quark masses a sine-Gordon kink chain is obtained which may be regarded as simplest realization of the Skyrme crystal for nuclear matter. Characteristic differences between confining and non-confining models are pointed out.Comment: 27 pages, 11 figures, added reference, corrected sig

Spatially heterogeneous ages in glassy dynamics

We construct a framework for the study of fluctuations in the nonequilibrium relaxation of glassy systems with and without quenched disorder. We study two types of two-time local correlators with the aim of characterizing the heterogeneous evolution: in one case we average the local correlators over histories of the thermal noise, in the other case we simply coarse-grain the local correlators. We explain why the former describe the fingerprint of quenched disorder when it exists, while the latter are linked to noise-induced mesoscopic fluctuations. We predict constraints on the pdfs of the fluctuations of the coarse-grained quantities. We show that locally defined correlations and responses are connected by a generalized local out-of-equilibrium fluctuation-dissipation relation. We argue that large-size heterogeneities in the age of the system survive in the long-time limit. The invariance of the theory under reparametrizations of time underlies these results. We relate the pdfs of local coarse-grained quantities and the theory of dynamic random manifolds. We define a two-time dependent correlation length from the spatial decay of the fluctuations in the two-time local functions. We present numerical tests performed on disordered spin models in finite and infinite dimensions. Finally, we explain how these ideas can be applied to the analysis of the dynamics of other glassy systems that can be either spin models without disorder or atomic and molecular glassy systems.Comment: 47 pages, 60 Fig

Capacitive tensiography: a new modality for the fiber drop multianalyser

The development of a new measurement modality for the fiber drop multianalyser is reported. The optrode used in earlier studies has been modified to permit simultaneous measurement of optical and capacitance information during drop formation. Measurements on a range of liquids are reported, and variations in the capacitance of the order of several percent are achieved. The dynamic range of this measurement channel is approximately 5500, although noise considerations reduce ths approximately by a factor of three. The ability of the new technique to discriminate between test solutions is analysed

Application of ultrasonic tensiography to analysis of red wine

An ultrasonic tensiographic system has recently been developed and described elsewhere. The system is based on the use of ultrasonic interferometry on liquid drops as they grow. Earlier results have demonstrated the capacity of this system to distinguish between different liquids, with particular emphasis on beverages. This system has now been applied to make measurements on a range of concentrations of red wine, and results are presented. The resulting characteristic curves are highly feature-rich, and show an evolution of these features with concentration. The measurements suggest that the system is currently capable of resolving concentration variations in red wine of approximately 1.5%, and is potentially capable of much finer resolution than this. The system response time is constrained only by the length of time required to grow a drop. In this case, drops are formed over a period of approximately 90-100 seconds, although it has been shown previously that there is sustantial leeway allowable in the flow rate without degradation of the results

The capacitive drop tensiometer: a novel multianalysing technique for measuring the properties of liquids

A new instrumental method for measuring the physical properties of a liquid has been developed. The instrument, called a capacitive drop tensiometer (CDT), is based on the drop volume principle in combination with a capacitive transducer. A delivery head with a specialized wetting design was constructed for forming drops. The capacitive transducer uses the delivery head as one of its plates and a cylindrical ring plate, which surrounds the delivery head and the space occupied by the drop that is formed, as another. Excellent linearity is achieved by optimizing the design, with an accuracy of drop volume measurement of approximately 2 mu l. The system is suitable for measuring both drops in equilibrium and those in the process of growing. Its capability of real-time measurement makes it particularly useful for volatile liquids, in which instance the measurement of drop volume using a flowmeter or a pump is no longer reliable. The CDT can also be used to determine concentration. It was found that the concentration curve is linear for aqueous glycerol solutions although not so for aqueous ethanol solutions. The CDT's ability to measure surface tension was also explored and experimental results are presented here

Application of capacitive tensiography to investigation of pendant drop growth

The new technique of capacitive tensiography is applied to monitor the formation of liquid drops under conditions of extremely slow growth. When drop growth is sufficiently slow, the effect of forces arising from surface tension due to the changing dimensions of the drop becomes evident. We present here the results showing qualitative variations in the signal representing drop growth over a range of flow rates, whose form is explicable by simple physical arguments based on the imbalance between the motive pressure, the weight of the drop and the opposing Laplace–Young pressure. It is proposed that this technique may be used to monitor capillary flow in more complex systems, and assist studies of drop growth