Reversible and irreversible evolution of a condensed bosonic gas

We have formulated a kinetic theory for a condensed atomic gas in a trap, i.e., a generalized Gross-Pitaevskii equation, as well as a quantum-Boltzmann equation for the normal and anomalous fluctuations [R. Walser et al., Phys. Rev. A, 59, 3878 (1999)]. In this article, the theory is applied to the case of an isotropic configuration and we present numerical and analytical results for the reversible real-time propagation, as well as irreversible evolution towards equilibrium.Comment: 15 pages RevTeX, 8 figures, reviewed PRA resubmissio

Quantum Kinetic Theory for a Condensed Bosonic Gas

We present a kinetic theory for Bose-Einstein condensation of a weakly interacting atomic gas in a trap. Starting from first principles, we establish a Markovian kinetic description for the evolution towards equilibrium. In particular, we obtain a set of self-consistent master equations for mean fields, normal densities, and anomalous fluctuations. These kinetic equations generalize the Gross-Pitaevskii mean-field equations, and merge them consistently with a quantum-Boltzmann equation approach.Comment: 15 pages, no figures; reviewed version; to be published in PR

Motion Tomography of a single trapped ion

A method for the experimental reconstruction of the quantum state of motion for a single trapped ion is proposed. It is based on the measurement of the ground state population of the trap after a sudden change of the trapping potential. In particular, we show how the Q function and the quadrature distribution can be measured directly. In an example we demonstrate the principle and analyze the sensibility of the reconstruction process to experimental uncertainties as well as to finite grid limitations. Our method is not restricted to the Lamb-Dicke Limit and works in one or more dimensions.Comment: 4 pages, Revtex format, 4 postscript figures, changed typographical error

Formation of Pairing Fields in Resonantly Coupled Atomic and Molecular Bose-Einstein Condensates

In this paper, we show that pair-correlations may play an important role in the quantum statistical properties of a Bose-Einstein condensed gas composed of an atomic field resonantly coupled with a corresponding field of molecular dimers. Specifically, pair-correlations in this system can dramatically modify the coherent and incoherent transfer between the atomic and molecular fields.Comment: 4 pages, 4 figure

Collective Feshbach scattering of a superfluid droplet from a mesoscopic two-component Bose-Einstein condensate

We examine the collective scattering of a superfluid droplet impinging on a mesoscopic Bose-Einstein condensate (BEC) as a target. The BEC consists of an atomic gas with two internal electronic states, each of which is trapped by a finite-depth external potential. An off-resonant optical laser field provides a localized coupling between the BEC components in the trapping region. This mesoscopic scenario matches the microscopic setup for Feshbach scattering of two particles, when a bound state of one sub-manifold is embedded in the scattering continuum of the other sub-manifold. Within the mean-field picture, we obtain resonant scattering phase shifts from a linear response theory in agreement with an exact numerical solution of the real time scattering process and simple analytical approximations thereof. We find an energy-dependent transmission coefficient that is controllable via the optical field between 0 and 100%.Comment: 4 Latex pages, including 4 figure

Equivalence of Kinetic Theories of Bose-Einstein Condensation

We discuss the equivalence of two non-equilibrium kinetic theories that describe the evolution of a dilute, Bose-Einstein condensed atomic gas in a harmonic trap. The second-order kinetic equations of Walser et al. [PRA 63, 013607 (2001)] reduce to the Gross-Pitaevskii equation and the quantum Boltzmann equation in the low and high temperature limits, respectively. These kinetic equations can thus describe the system in equilibrium (finite temperature) as well as in non-equilibrium (real time). We have found this theory to be equivalent to the non-equilibrium Green's function approach originally proposed by Kadanoff and Baym and more recently applied to inhomogeneous trapped systems by M. Imamovi\'c-Tomasovi\'c and A. Griffin [arXiv:cond-mat/9911402].Comment: REVTeX3, 6 pages, 2 eps figures, published version, minor change

Electrospinning Auricular Shaped Scaffolds for Tissue Engineering

Poly(ɛ)caprolactone scaffolds have been electrospun directly into an auricular shaped conductive mould. Bovine chondrocytes were harvested from articular cartilage and seeded onto 16 of the produced scaffolds, which received either an ethanol (group A) or a plasma treatment (group B) for sterilisation before seeding. The seeded scaffolds were cultured for 3 weeks in vitro and analysed with regard to total DNA and GAG content as well as the expression of AGG, COL1, COL2, MMP3 and MMP13. Rapid cell proliferation and GAG accumulation was observed until week 2. However, total DNA and GAG content decreased again in week 3. qPCR data shows a slight increase in the expression of anabolic genes and a slight decrease for the catabolic genes, with a significant difference between the groups A and B only for COL2 and MMP1

A quick method to isolate pure DNA from asexual spores of Coprinus cinereus for screening approaches

In this study, we present a glass bead-phenol method to isolate genomic DNA from oidia of the basidiomycete Coprinus cinereus. The DNA can be used in Southern blot analysis with digoxigenin-labelled DNA probes without the background problems encountered with DNA isolated from fungal mycelium. Furthermore, DNA isolated from oidia can be applied in PCR. This is especially useful when searching for specific DNA sequences or recombination events in a mixture of different strains