Truncation method for Green's functions in time-dependent fields

We investigate the influence of a time dependent, homogeneous electric field on scattering properties of non-interacting electrons in an arbitrary static potential. We develop a method to calculate the (Keldysh) Green's function in two complementary approaches. Starting from a plane wave basis, a formally exact solution is given in terms of the inverse of a matrix containing infinitely many 'photoblocks' which can be evaluated approximately by truncation. In the exact eigenstate basis of the scattering potential, we obtain a version of the Floquet state theory in the Green's functions language. The formalism is checked for cases such as a simple model of a double barrier in a strong electric field. Furthermore, an exact relation between the inelastic scattering rate due to the microwave and the AC conductivity of the system is derived which in particular holds near or at a metal-insulator transition in disordered systems.Comment: to appear in Phys. Rev. B., 21 pages, 3 figures (ps-files

Exploring Cutting Edge Technologies with MIDI Polyphonic Expression in Sampled Instruments

The intention of this project is to create a sample library that utilizes a new MIDI protocol called MIDI-Polyphonic Expression, which will be defined from here as “MPE”. This is done utilizing new MPE features in Ableton Live’s sampler device and Ableton racks to optimize workflow for the modern composer. Ableton’s incredibly powerful audio stretching and time warping features are responsible for many of the sounds we hear in popular music today, and now with the addition of MPE they are going to allow the possibility of more creative human expression. This library contains multiple layered samples in order to achieve a perceived sense of three dimensions of sound. All of the samples are recorded using high quality microphones and preamps in order to achieve the highest fidelity in the audio.https://remix.berklee.edu/graduate-studies-production-technology/1278/thumbnail.jp

A readiness model for implementation of Program Management.

Driven by spiraling costs and the increasing demands of consumers, workers and funding bodies, change is an ongoing and inevitable condition in the health care industry. Traditional structures, high professional differentiation and provider-centred processes have resulted in an inefficient system that requires radical change to meet the new demands of the environment and the market place. The literature on the shift towards decentralized organizational models such as Program Management, was reviewed. A Readiness Model was developed based upon the critical factors for successful implementation of Program Management as identified in the literature. A two part field study was then conducted in a multidivisional community hospital. Results confirmed that the critical factors identified in the literature were also viewed as critical factors in the study setting. Correlational analysis indicated a positive relationship between the perceived degree of development of the critical factors and the perceived success of implementation of Program Management. In the hospital studied, results for perceived readiness and perceived success ranked the hospital divisions highest to lowest for Rehabilitation, Regional Children\u27s Centre, Long Term Care and Acute Care. The most important factors were perceived to be interdisciplinary teamwork, a philosophy of client-centred care, and shared vision and values. The results suggested a model incorporating the concept of the critical factors with the concept of the team-based organization. Self directed teams must be supported by the critical factors as they develop processes to deliver client-centred care to specific program populations. The Readiness Model may be used by healthcare organizations to evaluate the level of development of critical factors and to target areas requiring further development in order to facilitate successful implementation of decentralized structures. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .B72. Source: Masters Abstracts International, Volume: 37-01, page: 0224. Adviser: Michael Prince. Thesis (M.B.A.)--University of Windsor (Canada), 1996

Noise enhancement due to quantum coherence in coupled quantum dots

We show that the intriguing observation of noise enhancement in the charge transport through two vertically coupled quantum dots can be explained by the interplay of quantum coherence and strong Coulomb blockade. We demonstrate that this novel mechanism for super-Poissonian charge transfer is very sensitive to decoherence caused by electron-phonon scattering as inferred from the measured temperature dependence.Comment: 4 pages, 3 figures, corrected version (Figs.2 and 3

Finite-Size Scaling Exponents in the Dicke Model

We consider the finite-size corrections in the Dicke model and determine the scaling exponents at the critical point for several quantities such as the ground state energy or the gap. Therefore, we use the Holstein-Primakoff representation of the angular momentum and introduce a nonlinear transformation to diagonalize the Hamiltonian in the normal phase. As already observed in several systems, these corrections turn out to be singular at the transition point and thus lead to nontrivial exponents. We show that for the atomic observables, these exponents are the same as in the Lipkin-Meshkov-Glick model, in agreement with numerical results. We also investigate the behavior of the order parameter related to the radiation mode and show that it is driven by the same scaling variable as the atomic one.Comment: 4 pages, published versio

Feedback Control of Quantum Transport

The current through nanostructures like quantum dots can be stabilized by a feedback loop that continuously adjusts system parameters as a function of the number of tunnelled particles $n$. At large times, the feedback loop freezes the fluctuations of $n$ which leads to highly accurate, continuous single particle transfers. For the simplest case of feedback acting simultaneously on all system parameters, we show how to reconstruct the original full counting statistics from the frozen distribution.Comment: 4 pages, 2 figure

Simultaneous Embeddability of Two Partitions

We study the simultaneous embeddability of a pair of partitions of the same underlying set into disjoint blocks. Each element of the set is mapped to a point in the plane and each block of either of the two partitions is mapped to a region that contains exactly those points that belong to the elements in the block and that is bounded by a simple closed curve. We establish three main classes of simultaneous embeddability (weak, strong, and full embeddability) that differ by increasingly strict well-formedness conditions on how different block regions are allowed to intersect. We show that these simultaneous embeddability classes are closely related to different planarity concepts of hypergraphs. For each embeddability class we give a full characterization. We show that (i) every pair of partitions has a weak simultaneous embedding, (ii) it is NP-complete to decide the existence of a strong simultaneous embedding, and (iii) the existence of a full simultaneous embedding can be tested in linear time.Comment: 17 pages, 7 figures, extended version of a paper to appear at GD 201