Grover's search algorithm: An optical approach

The essential operations of a quantum computer can be accomplished using solely optical elements, with different polarization or spatial modes representing the individual qubits. We present a simple all-optical implementation of Grover's algorithm for efficient searching, in which a database of four elements is searched with a single query. By `compiling' the actual setup, we have reduced the required number of optical elements from 24 to only 12. We discuss the extension to larger databases, and the limitations of these techniques.Comment: 6 pages, 5 figures. To appear in a special issue of the Journal of Modern Optics -- "The Physics of Quantum Information

Measuring a photonic qubit without destroying it

Measuring the polarisation of a single photon typically results in its destruction. We propose, demonstrate, and completely characterise a \emph{quantum non-demolition} (QND) scheme for realising such a measurement non-destructively. This scheme uses only linear optics and photo-detection of ancillary modes to induce a strong non-linearity at the single photon level, non-deterministically. We vary this QND measurement continuously into the weak regime, and use it to perform a non-destructive test of complementarity in quantum mechanics. Our scheme realises the most advanced general measurement of a qubit: it is non-destructive, can be made in any basis, and with arbitrary strength.Comment: 4 pages, 3 figure

On the unique possibility to increase significantly the contrast of dark resonances on D1 line of 87^{87}Rb

We propose and study, theoretically and experimentally, a new scheme of excitation of a coherent population trapping resonance for D1 line of alakli atoms with nuclear spin $I=3/2$ by bichromatic linearly polarized light ({\em lin}$||${\em lin} field) at the conditions of spectral resolution of the excited state. The unique properties of this scheme result in a high contrast of dark resonance for D1 line of $^{87}$Rb.Comment: 9 pages, 7 figures. This material has been partially presented on ICONO-2005, 14 May 2005, St. Petersburg, Russia. v2 references added; text is changed a bi

Quality of a Which-Way Detector

We introduce a measure Q of the "quality" of a quantum which-way detector, which characterizes its intrinsic ability to extract which-way information in an asymmetric two-way interferometer. The "quality" Q allows one to separate the contribution to the distinguishability of the ways arising from the quantum properties of the detector from the contribution stemming from a-priori which-way knowledge available to the experimenter, which can be quantified by a predictability parameter P. We provide an inequality relating these two sources of which-way information to the value of the fringe visibility displayed by the interferometer. We show that this inequality is an expression of duality, allowing one to trace the loss of coherence to the two reservoirs of which-way information represented by Q and P. Finally, we illustrate the formalism with the use of a quantum logic gate: the Symmetric Quanton-Detecton System (SQDS). The SQDS can be regarded as two qubits trying to acquire which way information about each other. The SQDS will provide an illustrating example of the reciprocal effects induced by duality between system and which-way detector.Comment: 10 pages, 5 figure

Current research, pressing issues, and lingering questions in marine invasion science: lessons from the Tenth International Conference on Marine Bioinvasions (ICMB-X)

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Fowler, A. E., Blakeslee, A. M. H., Bortolus, A., Dias, J., Tepolt, C. K., & Schwindt, E. Current research, pressing issues, and lingering questions in marine invasion science: lessons from the Tenth International Conference on Marine Bioinvasions (ICMB-X). Aquatic Invasions, 15(1), (2020): 1-10, doi:10.3391/ai.2020.15.1.01.Research on marine bioinvasions is an inherently international collaboration. Species range boundaries have become more fluid in recent decades as a result of enhanced human globalization, leading to species translocations across international boundaries through high profile vectors (e.g., shipping, hull fouling, aquaculture, etc.) (Ruiz et al. 2000; Seebens et al. 2013). Global trade and anthropogenic activities that promote invasive species spread continue to increase, rising by an average of 70% since 1970, with no sign of saturation (Pagad et al. 2015; Seebens et al. 2017). Even though these numbers are primarily based on terrestrial systems, recent work has demonstrated that marine ecosystems are as severely impacted by invasive species as by other human activities including overfishing, pollution (including plastics), climate change, and ocean acidification (Diaz et al. 2019). Species introductions to seas, coasts, and estuaries are therefore a global threat to human and non-human populations alike. As such, scientists and managers are increasingly focused on prevention and management, risk analysis and prioritization, and innovative technologies to detect novel species.The ICMB-X was supported by CONICET, MINCyT, SCTeIP Chubut, Consejo Federal de Inversiones, Biodiversity Heritage Library, Administración Portuaria de Puerto Madryn (APPM), Office of Naval Research Global, Aluar Aluminio Argentino, Madryn Bureau, Ente Mixto Puerto Madryn, Municipalidad de Puerto Madryn, and FAO-GEF-SAyDS

Versorgung und Reanimation des reifen Neugeborenen nach der Geburt : Basierend auf der aktuellen Leitlinie des European Resuscitation Council 2021

Zusammenfassung Die volle Reanimation eines Neugeborenen mit Beatmungen, Thoraxkompressionen und der Gabe von Medikamenten ist ein äußerst seltenes Ereignis, das selbst neonatologische Teams immer wieder vor Herausforderungen stellt. Gerade in diesen seltenen und häufig dramatischen Situationen ist schnelles und umsichtiges Handeln im Team gefragt. Dabei ist die effektivste und meist einzig notwendige Maßnahme für die erfolgreiche Versorgung eines nicht spontan atmenden Neugeborenen eine suffiziente Maskenbeatmung. Wird diese effektiv durchgeführt, sind beim Neugeborenen in den seltensten Fällen tatsächlich Thoraxkompressionen notwendig. Im März 2021 wurde vom European Resuscitation Council (ERC) die neue Leitlinie zur Reanimation von Neugeborenen publiziert. Auf Basis dieser Leitlinie beschreibt der vorliegende Beitrag detailliert den im Algorithmus der Versorgung und Reanimation von reifen Neugeborenen dargestellten Handlungsablauf. Er richtet sich damit einerseits insbesondere an NichtneonatologInnen, die für die Versorgung v. a. von reifen Neugeborenen nach der Geburt verantwortlich sind. Andererseits soll er auch jenen zur Unterstützung dienen, die medizinisches Personal in der Versorgung von lebensbedrohten Neugeborenen trainieren und den Algorithmus der Neugeborenenreanimation als didaktisches Konzept vermitteln. Abstract The resuscitation of a neonate with the need for ventilation, chest compressions and the administration of drugs is an extremely rare event that repeatedly challenges even neonatal teams. It is precisely in these rare and often dramatic situations that rapid and prudent team action is required. The most effective and usually the only necessary measure for the successful resuscitation of a neonate who is not breathing spontaneously is sufficient mask ventilation. If ventilation is performed effectively, chest compressions are rarely necessary in the neonate. In March 2021, the European Resuscitation Council (ERC) published the new guidelines for neonatal resuscitation. Based on these guidelines, this article describes in detail the course of action outlined in the algorithm for the stabilisation and resuscitation of term neonates. On the one hand, it is aimed at non-neonatologists who are responsible for the care of term neonates after birth. On the other hand, it is also intended to support those who train medical personnel in the care of life-threatened neonates and teach the algorithm of neonatal resuscitation as a didactic concept

An interferometric complementarity experiment in a bulk Nuclear Magnetic Resonance ensemble

We have experimentally demonstrated the interferometric complementarity, which relates the distinguishability $D$ quantifying the amount of which-way (WW) information to the fringe visibility $V$ characterizing the wave feature of a quantum entity, in a bulk ensemble by Nuclear Magnetic Resonance (NMR) techniques. We primarily concern on the intermediate cases: partial fringe visibility and incomplete WW information. We propose a quantitative measure of $D$ by an alternative geometric strategy and investigate the relation between $D$ and entanglement. By measuring $D$ and $V$ independently, it turns out that the duality relation $D^{2}+V^{2}=1$ holds for pure quantum states of the markers.Comment: 13 page, 5 PS figure

Global environmental changes: setting priorities for Latin American coastal habitats.

The definitive version is available at www.blackwell-synergy.comThe Intergovernmental Panel for Climate Change (IPCC) reports that Global Environmental Changes (GEC) are occurring quicker than at any other time over the last 25 million years and impacting upon marine environments (Bellard et al., 2012). There is overwhelming evidence showing that GEC are affecting both the quality and quantity of the goods and services provided by a wide range of marine ecosystems. In order to discuss regional preparedness for global environmental changes, a workshop was held in Ilhabela, Brazil (22- 26 April 2012) entitled "Evaluating the Sensitivity of Central and South American Benthic Communities to Global Environmental Changes" that drew together scientists from ten Latin American and three European countries. © 2013 Blackwell Publishing Ltd