Comment on "Loss-error compensation in quantum-state measurements"

In the two papers [T. Kiss, U. Herzog, and U. Leonhardt, Phys. Rev. A 52, 2433 (1995); U. Herzog, Phys. Rev. A 53, 1245 (1996)] with titles similar to the one given above, the authors assert that in some cases it is possible to compensate a quantum efficiency $\eta\leq 1/2$ in quantum-state measurements, violating the lower bound 1/2 proved in a preceding paper [G. M. D'Ariano, U. Leonhardt and H. Paul, Phys. Rev. A 52, R1801 (1995)]. Here we re-establish the bound as unsurpassable for homodyning any quantum state, and show how the proposed loss-compensation method would always fail in a real measurement outside the allowed $\eta >1/2$ region.Comment: 3 pages, RevTeX, 2 figures included, to appear on Phys. Rev. A (April 1998

Effective damping in the Raman cooling of trapped ions

We present a method of treating the interaction of a single three-level ion with two laser beams. The idea is to apply a unitary transformation such that the exact transformed Hamiltonian has one of the three levels decoupled for all values of the detunings. When one takes into account damping, the evolution of the system is governed by a master equation usually obtained via adiabatic approximation under the assumption of far-detuned lasers. To go around the drawbacks of this technique, we use the same unitary transformation to get an effective master equation.Comment: 15 pages, 5 figures. To appear in Optics Communication

Self-homodyne tomography of a twin-beam state

A self-homodyne detection scheme is proposed to perform two-mode tomography on a twin-beam state at the output of a nondegenerate optical parametric amplifier. This scheme has been devised to improve the matching between the local oscillator and the signal modes, which is the main limitation to the overall quantum efficiency in conventional homodyning. The feasibility of the measurement is analyzed on the basis of Monte-Carlo simulations, studying the effect of non-unit quantum efficiency on detection of the correlation and the total photon-number oscillations of the twin-beam state.Comment: 13 pages (two-column ReVTeX) including 21 postscript figures; to appear on Phys. Rev.

Nonlinear Decoherence in Quantum State Preparation of a Trapped Ion

We present a nonlinear decoherence model which models decoherence effect caused by various decohereing sources in a quantum system through a nonlinear coupling between the system and its environment, and apply it to investigating decoherence in nonclassical motional states of a single trapped ion. We obtain an exactly analytic solution of the model and find very good agreement with experimental results for the population decay rate of a single trapped ion observed in the NIST experiments by Meekhof and coworkers (D. M. Meekhof, {\it et al.}, Phys. Rev. Lett. {\bf 76}, 1796 (1996)).Comment: 5 pages, Revte

Engaging digital artworks through emotion: interface design case study

Artworks are often created to solicit emotional responses, yet the emotional elements are largely missing from artworks’ description and access options. In an effort to advance the design of emotion-based image retrieval systems, our study developed several research proposals for incorporating emotion into the description and access features of a digital artwork collection. Most of the proposed solutions for developing emotion metadata for artworks were informed by the current practices in information organization, including crowdsoursing and expert classifications. Being grounded in various emotion theories, the proposals offer a variety of ways to integrate emotion descriptors and navigation features into the interface design of a museum website. While the proposed solutions for integrating emotion features into online collections are not exhaustive, they highlight some of the design choices for developing emotion metadata, coding schemas and navigation features, and offer innovative ways to engage virtual visitors with museum digital collection.ye

Journeys from quantum optics to quantum technology

Sir Peter Knight is a pioneer in quantum optics which has now grown to an important branch of modern physics to study the foundations and applications of quantum physics. He is leading an effort to develop new technologies from quantum mechanics. In this collection of essays, we recall the time we were working with him as a postdoc or a PhD student and look at how the time with him has influenced our research

Homelessness and the Ethics of Information Access

Many public libraries have rules against strong body odor, bringing large amounts of luggage into the library, sleeping, and bathing in restrooms. These rules disproportionately affect library patrons who are experiencing homelessness. This paper reviews recent literature that considers legal and social justice perspectives on homelessness and libraries, as well as the policies of four urban public library systems. Though these rules may be legal and are widely used, people without homes have no other access to information. This paper concludes that blocking their access conflicts with the mission of public libraries to provide information to all. This is an Accepted Manuscript of an article published by Taylor & Francis Group in The Serials Librarian on 18/12/2015, available online: http://dx.doi.org/10.1080/0361526X.2015.1099590

Market performance of Nordic initial public offerings (IPOs) and its determinants

We study the short-run stock market performance of 219 Nordic initial public offerings (IPOs) listed between 2001 and 2016 and its determinants. Short-run stock market performance is measured by the first-day market-adjusted return. In order to identify determinants of short-run market performance we use multiple regression models with firm, market and offer specific variables in accordance with selected theories. We find that, overall, Nordic IPOs was underpriced with 4.53% on average. However, there are quite large differences in underpricing between the Nordic countries. Swedish IPOs had an average first-day return of 7.35% and Finnish 7.97%, Denmark had 5.58% while in Norway it was 0.60%. These findings suggest a downward sloping trend in the level of underpricing in the Nordics over the past decades. Furthermore, our results indicate that investor sentiment is a determinant of short-run performance of IPOs in the Nordics in general. We further find that hot issue markets, firm age, firm assets, pricing technique, offer price relative to file price range and the reputation of the underwriter are determinants of short-run market performance, but that these results vary by country, suggesting that there are different determinants of short-run performance within the Nordic countries. The overall findings on determinants support the investor sentiment theory, the hot market phenomenon and information revelation theory, while it is conflicting with the main implications of the winner`s curse theory