Full Stark control of polariton states on a spin-orbit hypersphere

The orbital angular momentum and the polarization of light are physical quantities widely investigated for classical and quantum information processing. In this work we propose to take advantage of strong light-matter coupling, circular-symmetric confinement, and transverse-electric transverse-magnetic splitting to exploit states where these two degrees of freedom are combined. To this end we develop a model based on a spin-orbit Poincaré hypersphere. Then we consider the example of semiconductor polariton systems and demonstrate full ultrafast Stark control of spin-orbit states. Moreover, by controlling states on three different spin-orbit spheres and switching from one sphere to another we demonstrate the control of different logic bits within one single physical system

Nanodot-Cavity Electrodynamics and Photon Entanglement

Quantum electrodynamics of excitons in a cavity is shown to be relevant to quantum operations. We present a theory of an integrable solid-state quantum controlled-phase gate for generating entanglement of two photons using a coupled nanodot-microcavity-fiber structure. A conditional phase shift of $O(\pi/10)$ is calculated to be the consequence of the giant optical nonlinearity keyed by the excitons in the cavities. Structural design and active control, such as electromagnetic induced transparency and pulse shaping, optimize the quantum efficiency of the gate operation.Comment: 4 pages 3 figure

Multicomponent polariton superfluidity in the optical parametric oscillator regime

Superfluidity, the ability of a liquid or gas to flow with zero viscosity, is one of the most remarkable implications of collective quantum coherence. In equilibrium systems like liquid 4He and ultracold atomic gases, superfluid behaviour conjugates diverse yet related phenomena, such as persistency of metastable flow in multiply connected geometries and the existence of a critical velocity for frictionless flow when hitting a static defect. The link between these different aspects of superfluid behaviour is far less clear in driven-dissipative systems displaying collective coherence, such as microcavity polaritons, which raises important questions about their concurrency. With a joint theoretical and experimental study, we show that the scenario is particularly rich for polaritons driven in a three-fluid collective coherent regime so-called optical parametric oscillator. On the one hand, the spontaneous macroscopic coherence following the phase locking of the signal and idler fluids has been shown to be responsible for their simultaneous quantized flow metastability. On the other hand, we show here that pump, signal and idler have distinct responses when hitting a static defect; while the signal displays hardly appreciable modulations, the ones appearing in pump and idler are determined by their mutual coupling due to nonlinear and parametric processes

Polariton Pattern Formation and Photon Statistics of the Associated Emission

We report on the formation of a diverse family of transverse spatial polygon patterns in a microcavity polariton fluid under coherent driving by a blue-detuned pump. Patterns emerge spontaneously as a result of energy-degenerate polariton-polariton scattering from the pump state to interfering high order vortex and antivortex modes, breaking azimuthal symmetry. The interplay between a multimode parametric instability and intrinsic optical bistability leads to a sharp spike in the value of second order coherence g (2)(0) of the emitted light, which we attribute to the strongly superlinear kinetics of the underlying scattering processes driving the formation of patterns. We show numerically by means of a linear stability analysis how the growth of parametric instabilities in our system can lead to spontaneous symmetry breaking, predicting the formation and competition of different pattern states in good agreement with experimental observations

Risk Factors for operated carpal tunnel syndrome: a multicenter population-based case-control study

This article is available from: http://www.biomedcentral.com/1471-2458/9/34

Vortices in polariton OPO superfluids

This chapter reviews the occurrence of quantised vortices in polariton fluids, primarily when polaritons are driven in the optical parametric oscillator (OPO) regime. We first review the OPO physics, together with both its analytical and numerical modelling, the latter being necessary for the description of finite size systems. Pattern formation is typical in systems driven away from equilibrium. Similarly, we find that uniform OPO solutions can be unstable to the spontaneous formation of quantised vortices. However, metastable vortices can only be injected externally into an otherwise stable symmetric state, and their persistence is due to the OPO superfluid properties. We discuss how the currents charactering an OPO play a crucial role in the occurrence and dynamics of both metastable and spontaneous vortices.Comment: 40 pages, 16 figure

Biodiversity patterns of dry grasslands in the Central Apennines (Italy) along a precipitation gradient : experiences from the 10th EDGG Field Workshop

The 10th EDGG Field Workshop took place in a sector of the Central Apennine Mountains, Italy, in June 2017. Altogether, 22 researchers from nine European and Asian countries attended this Field Workshop. We sampled plant and insect biodiversity in submontane and lower-montane grasslands along a precipitation gradient, from the L’Aquila valley and the Fucino basin to the “Abruzzo, Lazio & Molise” National Park. The standardized EDGG sampling protocol, involving nested-plot series and additional 10-m2 relevés, was used. In the course of seven days of intensive fieldwork, we sampled 20 biodiversity plots along with 57 additional normal plots (yielding a total dataset of 97 10-m2 plots). Methodological additions tested in this workshop included the assessment of observer-related error (around 12% of the 10-m2 plots was resurveyed by a different team). In all plots, vascular plants, bryophytes and lichens were sampled. At each nested-plot series, also insects (Auchenorrhyncha) were sampled by local specialists, who developed an ad-hoc sampling procedure

NEW RECORDS OF NATIVE AND ALIEN VASCULAR PLANTS FROM ABRUZZO, LAZIO AND MOLISE NATIONAL PARK (ITALY) – AND ADDITIONS TO THE FLORA OF ABRUZZO AND MOLISE ADMINISTRATIVE REGIONS

The Abruzzo, Lazio and Molise National Park, a flagship conservation area in Italy, is a hotspot of floristic diversity and a crossroad for plant biogeography. In this work, as a result of recent field studies in the Park and herbarium revisions, we report 10 taxa new or confirmed for the Abruzzo administrative region, and 3 for the Molise administrative region. Moreover, 47 taxa of vascular plants (41 native and 6 alien taxa) that are new or confirmed for the flora of the Park are reported. Five taxa are excluded from the flora of the Park

NEW RECORDS OF NATIVE AND ALIEN VASCULAR PLANTS FROM ABRUZZO, LAZIO AND MOLISE NATIONAL PARK (ITALY) - AND ADDITIONS TO THE FLORA OF ABRUZZO AND MOLISE ADMINISTRATIVE REGIONS

The Abruzzo, Lazio and Molise National Park, a flagship conservation area in Italy, is a hotspot of floristic diversity and a crossroad for plant biogeography. In this work, as a result of recent field studies in the Park and herbarium revisions, we report 10 taxa new or confirmed for the Abruzzo administrative region, and 3 for the Molise administrative region. Moreover. 47 taxa of vascular plants (41 native and 6 alien taxa) that are new or confirmed for the flora of the Park are reported. Five taxa are excluded from the flora of the Park

Balancing Valued Tradition With Innovation When your product is a beloved classic, how do you update it to attract new customers?

Successful companies frequently face the challenge of updating a beloved old product. Italian opera companies face this dilemma every season. Many of the best-loved operas in the repertoire are more than 100 years old. The most devoted operagoers will have seen multiple productions of the same work and have a very clear, and usually conservative, notion of what constitutes a proper production. However, making no changes would limit opera’s contemporary cultural relevance. After interviewing 15 artistic directors of Italian opera houses and studying the ticket sales of 2,627 opera productions between 1989 and 2011, we found that the most successful opera houses strategically balance alterations to core and peripheral features of traditional operas across different customer segments. In so doing, they address the need for renewal while at the same time remaining sensitive to the heterogeneity of their audience. The findings offer several actionable insights for successfully navigating the innovation tradition tradeoff that companies across many industries must routinely face