Tripartite quantum state mapping and discontinuous entanglement transfer in a cavity QED open system

We describe the transfer of quantum information and entanglement from three flying (radiation) to three localized (atomic) qubits via cavity modes resonantly coupled to the atoms, in the presence of a common reservoir. Upon addressing the full dynamics of the resulting nine-qubit open system, we find that once the cavities are fed, fidelity and transferred entanglement are optimal, while their peak values exponentially decrease due to dissipative processes. The external radiation is then turned off and quantum correlations oscillate between atomic and cavity qubits. For a class of mixtures of W and GHZ input states we deal with a discontinuous exchange of entanglement among the subsystems, facing the still open problem of entanglement sudden death and birth in a multipartite system.Comment: 7 pages, 6 figures, 2 table

Effect of dissolved oxygen and chemical oxygen demand to nitrogen ratios on the partial nitrification/denitrification process in moving bed biofilm reactors

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewater with high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO) and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal from synthetic wastewater was investigated. Experiments were conducted in moving bed biofilm reactors (MBBRs) on partial nitrification process in pilot-plant configuration for 300 days. DO levels were changed from 0.04 to 0.12 and 0.42 to 3.4 mg/l in the anoxic (R1) and aerobic (R2) reactors, respectively. The optimum DO for partial nitrification was between 1-1.5 mg/l in the aerobic reactor (R2). Influent COD/N ratios between 20 and 2 g COD/g-N were tested by changing the nitrogen loading rate (NLR) supplied to the pilot plant. During operational conditions when the DO concentration in aerobic reactor was above 1 mg/l, near complete organic carbon removal occurred in the total MBBRs system. The effluent total nitrogen concentration in the operational conditions (1.7-2.1 mg O2/l and NH+ 4-N=35.7 mg N/l) was obtained in the range of 0.85-2 mg/l. The highest nitrite accumulation (50%- 52%) took place at the DO concentration of 1-1.5 mg/l and increased with decreasing COD/N ratio in aerobic reactor (R2). This study showed that the average nitrification rate at various COD/N ratios is about 0.96 gN/m2 per day while the maximum nitrification rate is about 2 gN/m2 per day at COD/N ratios lower than 6. The experimental COD/N ratio for denitrification was close to complete sum of NO2 - and NO3 - (NOx) removal efficiency (about 99%) at COD/N ratio equal 14 in the operational conditions in the anoxic reactor (R1)

Backscattering Differential Ghost Imaging in Turbid Media

In this Letter we present experimental results concerning the retrieval of images of absorbing objects immersed in turbid media via differential ghost imaging (DGI) in a backscattering configuration. The method has been applied, for the first time to our knowledge, to the imaging of small thin black objects located at different depths inside a turbid solution of polystyrene nanospheres and its performances assessed via comparison with standard imaging techniques. A simple theoretical model capable of describing the basic optics of DGI in turbid media is proposed.Comment: 5 pages, 6 figure

INTREPID Futures Initiative: The future of Academia and trans-disciplinary knowledge production in the urban field, 6th INTREPID Report

The idea of hosting the 5th INTREPID Action Workshop in Gagliato, Calabria (Italy), between the 20th - 27th July 2017, raised during the London Workshop with the deliberate intention to embed one of the INTREPID research explorations within ongoing initiatives of some of the Universities involved in the INTREPID COST action: in particular a participatory design workshop on Creative Towns, coordinated by the University of Westminster, with the participation of Newcastle University. Other non-cost members involved are: ILAUD, The International Laboratory of Architecture and Urban Design, the London School of Economics, the Universita’ degli Studi Mediterranea di Reggio Calabria, the Università della Calabria and a local NGO, the Academy of the Nano-science of Gagliato. The participatory workshop has been funded by the Academy of the Nano-science of Gagliato and it has been fruitfully coupled with an INTREPID Workshop. The main aim of the participatory design workshop was to explore alternative scenarios for the sustainable local development of Gagliato, a small town located in a relative marginal area of the South of Italy, engaging various local stakeholders in the scenario exercise

Quantum Probes for Ohmic Environments at Thermal Equilibrium

It is often the case that the environment of a quantum system may be described as a bath of oscillators with Ohmic density of states. In turn, the precise characterization of these classes of environments is a crucial tool to engineer decoherence or to tailor quantum information protocols. Recently, the use of quantum probes in characterizing Ohmic environments at zero-temperature has been discussed, showing that a single qubit provides precise estimation of the cutoff frequency. On the other hand, thermal noise often spoil quantum probing schemes, and for this reason we here extend the analysis to complex system at thermal equilibrium. In particular, we discuss the interplay between thermal fluctuations and time evolution in determining the precision {attainable by} quantum probes. Our results show that the presence of thermal fluctuations degrades the precision for low values of the cutoff frequency, i.e. values of the order $\omega_c \lesssim T$ (in natural units). For larger values of $\omega_c$ decoherence is mostly due to the structure of environment, rather than thermal fluctuations, such that quantum probing by a single qubit is still an effective estimation procedure.Comment: Entropy, special issue on Open Quantum Systems (OQS) for quantum technologies (S. Lorenzo and M. G. Palma, Eds

Transnational feminism: political strategies and theoretical resources

Despite sharing many successes at promoting international collaboration, enabling effective responses to politically powerful states, increasing awareness of formerly invisible violations of the human rights of women, and gaining ground in many countries and in international law, women’s human rights activists have many differences among them—in resources, location, issue-focus and strategies. It is appropriate to pay attention to these differences, particularly as they create challenges to the movement for women’s rights. However, we argue that the women’s human rights discourse—as developed and deployed by women’s human rights activists—can be a resource for addressing these challenges internal to the movement while facing current challenges from outside the movement. Attentive to the politics of defining a movement and its spokespeople, the article includes an extensive methodological discussion. We arrive at our conclusions after observing a broad range of women’s activism and interpreting the reflections of a wide range of activists. Taken together, they offer a view of human rights as indivisible and of the rights of all humans as interrelated. This view is useful for self-reflection within women’s movements and for the ability of participants of various women’s movements to use the women’s human rights framework for meeting contemporary challenges.This report was commisioned by International Relation

The coherent interaction between matter and radiation - A tutorial on the Jaynes-Cummings model

The Jaynes-Cummings (JC) model is a milestone in the theory of coherent interaction between a two-level system and a single bosonic field mode. This tutorial aims to give a complete description of the model, analyzing the Hamiltonian of the system, its eigenvalues and eigestates, in order to characterize the dynamics of system and subsystems. The Rabi oscillations, together with the collapse and revival effects, are distinguishing features of the JC model and are important for applications in Quantum Information theory. The framework of cavity quantum electrodynamics (cQED) is chosen and two fundamental experiments on the coherent interaction between Rydberg atoms and a single cavity field mode are described.Comment: 22 pages, 7 figures. Tutorial. Submitted to a special issue of EPJ - ST devoted to the memory of Federico Casagrand