Spin Squeezing with Coherent Light via Entanglement Swapping

We analyze theoretically a scheme that produces spin squeezing via the continuous swapping of atom-photon entanglement into atom-atom entanglement, and propose an explicit experimental system where the necessary atom-field coupling can be realized. This scheme is found to be robust against perturbations due to other atom-field coupling channels.Comment: 6 pages, 10 figure

Spatial Distribution of the Incompressible Strips at Aharonov-Bohm Interferometer

In this work, the edge physics of an Aharonov-Bohm interferometer (ABI) defined on a two dimensional electron gas, subject to strong perpendicular magnetic field B, is investigated. We solve the three dimensional Poisson equation using numerical techniques starting from the crystal growth parameters and surface image of the sample. The potential profiles of etched and gate defined geometries are compared and it is found that the etching yields a steeper landscape. The spatial distribution of the incompressible strips is investigated as a function of the gate voltage and applied magnetic field, where the imposed current is confined to. AB interference is investigated due to scattering processes between two incompressible "edge-states".Comment: 5 pages, 3 figure

Metal nanoparticle plasmons operating within quantum lifetime

We investigate the dynamics of a plasmonic oscillation over a metal nanoparticle when it is strongly coupled to a quantum emitter (e.g. quantum dot, molecule). We simulate the density matrix evolution for a simple model; coupled classical--quantum oscillators system. We show that lifetime of the plasmonic oscillations can be increased several orders of magnitude, upto the decay time of the quantum emitter. This effect shows itself as the narrowing of the plasmon emission band in the spaser (surface plasmon amplification by stimulated emission of radiation) experiment [{\it Nature}, {\bf 2009}, 460, 1110], where a gold nanoparticle interacts with the surrounding molecules. Enhancement of the plasmonic excitation lifetime enables stimulated emission to overcome the spontaneous one. The enhancement occurs due to the emergence of a phenomenon analogous to electromagnetically induced transparency (EIT). The effect can find applications in many areas of nanoscale physics, such as in quantum information with plasmons and in increasing solar cell efficiency.Comment: 9 pages, 7 figure

On LDPC Codes for Gaussian Interference Channels

In this paper, we focus on the two-user Gaussian interference channel (GIC), and study the Han-Kobayashi (HK) coding/decoding strategy with the objective of designing low-density parity-check (LDPC) codes. A code optimization algorithm is proposed which adopts a random perturbation technique via tracking the average mutual information. The degree distribution optimization and convergence threshold computation are carried out for strong and weak interference channels, employing binary phase-shift keying (BPSK). Under strong interference, it is observed that optimized codes operate close to the capacity boundary. For the case of weak interference, it is shown that via the newly designed codes, a nontrivial rate pair is achievable, which is not attainable by single user codes with time-sharing. Performance of the designed LDPC codes are also studied for finite block lengths through simulations of specific codes picked from the optimized degree distributions.Comment: ISIT 201

Superradiance induced topological vortex phase in a Bose-Einstein condensate

We investigate theoretically a topological vortex phase transition induced by a superradiant phase transition in an atomic Bose-Einstein condensate driven by a Laguerre-Gaussian optical mode. We show that superradiant radiation can either carry zero angular momentum, or be in a rotating Laguerre-Gaussian mode with angular momentum. The conditions leading to these two regimes are determined in terms of the width for the pump laser and the condensate size for the limiting cases where the recoil energy is both much smaller and larger than the atomic interaction energy.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Photonic Band Gap in the Triangular Lattice of BEC vortices

We investigate the photonic bands of an atomic Bose-Einstein condensate with a triangular vortex lattice. Index contrast between the vortex cores and the bulk of the condensate is achieved through the enhancement of the index via atomic coherence. Frequency dependent dielectric function is used in the calculations of the bands, resulting in photonic band gap widths of a few MHz.Comment: 8 pages, 6 figure

The influence of thickness and ammonia flow rate on the properties of AIN layers

Cataloged from PDF version of article.Undoped AlN layers have been grown on c-plane sapphire substrates by metal-organic chemical vapor deposition in order to study the effects of ammonia (NH3) flow rate and layer thickness on the structural quality and surface morphology of AlN layers by high-resolution X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Lower NH3 flow rate improves crystallinity of the symmetric (0 0 0 2) plane in AlN layers. Ammonia flow rate is also correlated with surface quality; pit-free and smooth AlN surfaces have been obtained at a flow rate of 70 standard cm(3) per minute. Thicker AlN films improve the crystallinity of the asymmetric (1 0 1 (1) over bar 2) plane. (c) 2011 Elsevier Ltd. All rights reserved

Genel Olarak Pazarlama Kavramı ve Turizm Pazarlaması

İnsanlık tarihinin başlangıcından beri insanların ihtiyaçları, istekleri ve daha fazlasına sahip olma arzuları varolagelmiştir. Tarım toplumlarında bu ihtiyaçlarını değiş-tokuş yöntemiyle gidermeye çalışan insanlar özellikle makine ve kitle üretimine geçişin sağlandığı Sanayi Devrimi ile birlikte ihtiyaçlarından daha fazlasının üretildiği bir dönemi yaşamaya başlamışlardır. Bu dönemde işletmeler; müşterileri kendilerine çekebilmek adına farklı pazarlama stratejilerini izlemeye ve farklı pazarlama anlayışlarını benimsemeye başlamışlardır. Pazarlamanın düşüncesinin gelişimine bakıldığında üretimin aşamalarıyla aynı yönde bir gelişme gösterdiği görülmektedir. Günümüzde de işletmeler ihtiyaçları çerçevesinde her geçen gün yeni bir çağdaş pazarlama anlayışını uygulamaya koymaktadırlar. Turizm hem ekonomik hemde akademik önemi ve değeri geç keşfedilen sektörlerden birisidir. Turizm alanındaki çalışmalar diğer temel alanlardan çok sonra başlasa da günümüzde aynı seviyede ilerleme yolundadır. Endüstri sektörü ve işletmeleri üzerine yoğunlaşan endüstri pazarlamasından otuz yıl kadar sonra turizm pazarlamasına da değinilmeye başlanmıştır. Bu gecikmenin arka planında ise turizmin ekonomik, toplumsal ve işletmecilik değerinin geç farkedilmesinin rolü büyüktür

Effects of emotion and perspective on remembering events: An eye-tracking study

The main objective of this study is to investigate the effects of the emotional content of an event and participants’ perspective on the memory and eye-tracking measurements for central and peripheral de-tails. The data have been collected from 130 undergraduate male students (18- 33 ages). Three series of seven different emotional thematic photographs (positive, negative, neutral) were used. Participants were subjected to only one of the three series, either in his own perspective condition or observer perspective condition. During the presentation of thematic photograph series participants’ eye movements were re-corded. All analysis for memory and eye-tracking measurements were carried out with 3 (Emotional Content: Positive, Negative, Neutral) X 2 (Participants’ perspective: Own perspective, observer perspec-tive) between-subjects factorial ANOVA. The results indicated that although central and peripheral de-tails took almost equal attention in both negative and neutral events, only details of the negative event was remembered better. In addition, when compared to negative and neutral events participants looked longer at positive event’s central details as well as peripheral details, only details of negative event were remembered better. Consequently, memory enhancement effect occured only in negative emotional event both for central and peripheral details, even though participants paid less or equal attention these details. In addition to effects of emotion, it was seen that like autobiographical memory (Nigro and Neisser, 1983) participants’ perspective has also an effect on event memory and attention measured by eye-tracking. According to eye-tracking results looking with his own perspective to the event causes narrowing of attention while looking with observer’s perspective to event causes extending of attention. In memory results it was seen that participants in his own perspective condition remembered central details better than participants in the observer condition. In conclusion, it is observed that enhanced memory for neg-ative emotional event can occur independently of attention, so it could be said that attention is not suffi-cient by itself to remember an event with details, emotional dimension of the event has a decisive role. Additionally, perspective have an effect on attention as well as event memory

An Action Research to Overcome Undergraduates’ Laboratory Anxiety

AbstractIn this study, it was aimed to determine and overcome undergraduates’ laboratory anxiety. For this purpose, Laboratory Anxiety Questionnaire (LAQ) was developed by researchers. LAQ was applied to 92 undergraduates as a pre-test and focus group interviews were performed to determine their laboratory anxiety. An action research was conducted by researchers. After instruction was accomplished in ten weeks, LAQ was applied as post-test. According to results, it was found that undergraduates’ laboratory anxiety related to working chemicals especially acids, using laboratory materials and equipments, laboratory accidents and making mistake, which were determined in the pre-test, were overcame in highly percentages