Transport Properties of Solitons

We calculate in this article the transport coefficients which characterize the dynamics of solitons in quantum field theory using the methods of dissipative quantum systems. We show how the damping and diffusion coefficients of soliton-like excitations can be calculated using the integral functional formalism. The model obtained in this article has new features which cannot be obtained in the standard models of dissipation in quantum mechanics.Comment: 16 Pages, RevTeX, Preprint UIU

Topological Defects and CMB anisotropies : Are the predictions reliable ?

We consider a network of topological defects which can partly decay into neutrinos, photons, baryons, or Cold Dark Matter. We find that the degree-scale amplitude of the cosmic microwave background (CMB) anisotropies as well as the shape of the matter power spectrum can be considerably modified when such a decay is taken into account. We conclude that present predictions concerning structure formation by defects might be unreliable.Comment: 14 pages, accepted for publication in PR

Magnetic Catalysis: A Review

We give an overview of the magnetic catalysis phenomenon. In the framework of quantum field theory, magnetic catalysis is broadly defined as an enhancement of dynamical symmetry breaking by an external magnetic field. We start from a brief discussion of spontaneous symmetry breaking and the role of a magnetic field in its a dynamics. This is followed by a detailed presentation of the essential features of the phenomenon. In particular, we emphasize that the dimensional reduction plays a profound role in the pairing dynamics in a magnetic field. Using the general nature of underlying physics and its robustness with respect to interaction types and model content, we argue that magnetic catalysis is a universal and model-independent phenomenon. In support of this claim, we show how magnetic catalysis is realized in various models with short-range and long-range interactions. We argue that the general nature of the phenomenon implies a wide range of potential applications: from certain types of solid state systems to models in cosmology, particle and nuclear physics. We finish the review with general remarks about magnetic catalysis and an outlook for future research.Comment: 37 pages, to appear in Lect. Notes Phys. "Strongly interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Yee. Version 2: references adde

Noncommutative Fluids

We review the connection between noncommutative gauge theory, matrix models and fluid mechanical systems. The noncommutative Chern-Simons description of the quantum Hall effect and bosonization of collective fermion states are used as specific examples.Comment: To appear in "Seminaire Poincare X", Institut Henri Poincare, Paris; references adde

Properties of the Top Quark

The top quark was discoverd at the CDF and D0 experiments in 1995. As the partner of the bottom quark its properties within the Standard Model are fully defined. Only the mass is a free parameter. The measurement of the top quark mass and the verification of the expected properties have been an important topic of experimental top quark physics since. In this review the recent results on top quark properties obtained by the Tevatron experiments CDF and D0 are summarised. At the advent of the LHC special emphasis is given to the basic measurement methods and the dominating systematic uncertainties.Comment: Habilitation thesis, revised and updated for publication in EPJ

Is conscious processing required for long-term memory?

Models of memory (including those of the SAM-REM variety) are generally based on the assumption that storage of information in long-term memory is a function of the amount of elaborative processing given to the processed information. Here we explore the limits of such an assumption by examining the long-term effects of information that has only been processed at a subliminal level. We conclude that even subliminally presented information is stored to some extent and will lead to small but consistent effects in indirect memory tests but not on direct memory tests. To have an effect on a direct memory test, the information has to be clearly seen (as in the RSVP experiments discussed in this chapter) although here again, attentive processing does not appear to be required

The combined effects on neuronal activation and blood–brain barrier permeability of time and n-3 polyunsaturated fatty acids in mice, as measured in vivo using MEMRI

N-3 polyunsaturated fatty acids (n-3 PUFA) are known to have cardiovascular and neuroprotective properties in both humans and rodents. Here, we use manganese-enhanced magnetic resonance imaging (MEMRI) to compare the effects of these polyunsaturated fatty acids on the combined effects of neuronal activity and integrity of blood–brain barrier integrity with saturated fatty acids from buttermilk. C57BL/6 mice (4 weeks old) were fed isocaloric diets containing 3% fish oil (3% FO, n = 5), 12% fish oil (FO, n = 6), 3% buttermilk (3% BM, n = 6) or 12% buttermilk (12% BM, n = 6) for 6 months. Following metabolic cage analysis these mice were scanned using a standard MEMRI protocol at 28–32 weeks of age. Adult mice aged 28–32 weeks old (RM3, n = 5) and 15–16 weeks old (YRM3, n = 4) maintained on standard rodent chow were also studied to assess age-related changes in brain barrier systems and neuronal activity. Signal intensity (SI) in the anterior pituitary (AP), arcuate hypothalamic nucleus (ARC), ventromedial hypothalamic nucleus (VMH) and the paraventricular hypothalamic nucleus (PVN) was significantly reduced in young compared to older mice fed standard chow. Furthermore, fish oil supplementation led to a decrease in SI within the ARC and PVN, reaching significance in the VMH in age-matched controls. Interestingly, both fish oil and buttermilk supplementation resulted in a significant increase in SI within the AP, a structure outside the BBB. We conclude that MEMRI is able to detect the combined effects of the integrity of neuronal activity and blood–brain barrier permeability in the hypothalamus associated with dietary manipulation and aging