A geometric phase for superconducting qubits under the decoherence effect

We propose a relaxation rate or dissipative cavity-based parameters that can be used as indicators of the stationary limit of a mixed state geometric phase. We perform our considerations for the system of a superconducting qubit in an open transmission line or interacting with a dissipative cavity. This system is very useful for performing an effective quantum computation by exhibiting the long collapse time of the geometric phase. It is shown that the geometric phase in the stationary limit does not depend on interaction time if the decay time exceeds an upper bound.     

Quantum Transfer Energy and Nonlocal Correlation in a Dimer with Time-Dependent Coupling Effect

The presence of coherence phenomenon due to the interference of probability amplitude terms, is one of the most important features of quantum mechanics theory. Recent experiments show the presence of quantum processes whose coherence provided over suddenly large interval-time. In particular, photosynthetic mechanisms in light-harvesting complexes provide oscillatory behaviors in quantum mechanics due to quantum coherence. In this work, we investigate the coherent quantum transfer energy for a single-excitation and nonlocal correlation in a dimer system modelled by a two-level atom system with and without time-dependent coupling effect. We analyze and explore the required conditions that are feasible with real experimental realization for optimal transfer of quantum energy and generation of nonlocal quantum correlation. We show that the enhancement of the probability for a single-excitation transfer energy is greatly benefits from the combination of the energy detuning and time-dependent coupling effect. We investigate the presence of quantum correlations in the dimer using the entanglement of formation. We also find that the entanglement between the donor and acceptor is very sensitive to the physical parameters and it can be generated during the coherent energy transfer. On the other hand, we study the dynamical behavior of the quantum variance when performing a measurement on an observable of the density matrix operator. Finally, an interesting relationship between the transfer probability, entanglement and quantum variance is explored during the time evolution in terms of the physical parameters.     

Quantum quantifiers of Raman photon pairs with relativistic motion

In this paper, we develop a model for four-level double Raman pairs by exploiting the required optimal conditions for this system that are feasible with real experimental realization. We investigate qualitatively the entanglement, statistical properties, and geometric phase for the pair of Stokes and anti-Stokes photons in the presence of the relativistic motion. We show that these quantifiers are very sensitive to the change of the Rabi frequency under relativistic motion, exhibiting substantial phenomena that depend on this kind of the coupling between the atom and photons. Finally, we explore the relationship between the quantum quantifiers for constant and time-dependent coupling.     

Quantum and Classical Correlations for Interacting and Noninteracting Qubits in Contact with Different Environments

We study the time evolution of the classical and quantum correlations for interacting and noninteracting two-qubit systems under the influence of noncorrelated and correlated environmental models. We discuss the dependence of different physical quantifiers on the environment parameters. Interestingly, we examine the effects of the initial state and different system parameters on the evolution of correlations of the system of qubits in contact with different kinds of environments. We show how the interaction among qubits can protect and preserve the correlation loss during the time evolution for various environmental models. Moreover, we examine the competition between the dissipative and coherent effects in different kinds of correlations dynamics of the system of qubits. Our study gives a deeper understanding on the correlations for a wide variety of the environment models, which is rather significant in different tasks of quantum optics and information.     

Mecanisme de l'homologation directe d'acetyleniques en allenes

Homologation of a terminal acetylene to an allene is easily accomplished in a “one-flask” process, via a Mannich base which is transformed to the desired allene by a 1–5 hydrogen shift.     

Bio-Inspired Rhamnolipids,Cyclic Lipopeptides and a Chito-Oligosaccharide Confer Protection against Wheat Powdery Mildew and Inhibit Conidia Germination

Plant protection is mainly based on the application of synthetic pesticides to limit yield losses resulting from diseases. However, the use of more eco-friendly strategies for sustainable plant protection has become a necessity that could contribute to controlling pathogens through a direct antimicrobial effect and/or an induction of plant resistance. Three different families of natural or bioinspired compounds originated from bacterial or fungal strains have been evaluated to protect wheat against powdery mildew, caused by the biotrophic Blumeria graminis f.sp. tritici (Bgt). Thus, three bio-inspired mono-rhamnolipids (smRLs), three cyclic lipopeptides (CLPs, mycosubtilin (M), fengycin (F), surfactin (S)) applied individually and in mixtures (M + F and M + F + S), as well as a chitosan oligosaccharide (COS) BioA187 were tested against Bgt, in planta and in vitro. Only the three smRLs (Rh-Eth-C12, Rh-Est-C12 and Rh-Succ-C12), the two CLP mixtures and the BioA187 led to a partial protection of wheat against Bgt. The higher inhibitor effects on the germination of Bgt spores in vitro were observed from smRLs Rh-Eth-C12 and Rh-Succ-C12, mycosubtilin and the two CLP mixtures. Taking together, these results revealed that such molecules could constitute promising tools for a more eco-friendly agriculture.     

On the performance of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3: the influence of preparation method

Research on Chemical Intermediates - The selective catalytic reduction of NO with ammonia (NH3-SCR) in the presence of H2O was studied over a series of Fe-Cu-ZSM-5 catalysts prepared by solid-state...     

Dephasing Process of a Single Atom Interacting with a Two-Mode Field

We consider the interaction of a qubit system with a two-mode field in the presence of multi-photon transition and phase damping effect. We use the master equation to obtain the density operator when the qubit is initially prepared in its excited state and the field is in a finite-dimensional pair coherent state. The properties of the considered system, such as the population inversion, amount of the mixedness, parameter estimation, and squeezing, are explored for one- and two-photon transitions. The effects of photon addition to the field and phase damping on the evaluation of these quantumness measures are also investigated.