The Mayer series of the Lennard-Jones gas: improved bounds for the convergence radius

We provide a lower bound for the convergence radius of the Mayer series of the Lennard-Jones gas which strongly improves on the classical bound obtained by Penrose and Ruelle 1963. To obtain this result we use an alternative estimate recently proposed by Morais et al. (J. Stat. Phys. 2014) for a restricted class of stable and tempered pair potentials (namely those which can be written as the sum of a non-negative potential plus an absolutely integrable and stable potential) combined with a method developed by Locatelli and Schoen (J. Glob. Optim. 2002) for establishing a lower bound for the minimal interatomic distance between particles interacting via a Morse potential in a cluster of minimum-energy configurations

Hybrid photonic entanglement: Realization, characterization and applications

We show that the quantum disentanglement eraser implemented on a two-photon system from parametric down-conversion is a general method to create hybrid photonic entanglement, namely the entanglement between different degrees of freedom of the photon pair. To demonstrate this, we generate and characterize a source with tunable degree of hybrid entanglement between two qubits, one encoded in the transverse momentum and position of a photon, and the other in the polarization of its partner. In addition, we show that a simple extension of our setup enables the generation of two-photon qubit-qudit hybrid entangled states. Finally, we discuss the advantages that this type of entanglement can bring for an optical quantum network.Comment: Published versio

METÁFORA E COGNIÇÃO: RESULTADO DE UM ESTUDO DE CASO

O texto literário usa de todas as modalidades da língua e de toda a criatividade do falante, o que lhe assegura a condição de ser o mais metafórico, o mais plástico dentre todos os textos: utópico e ideológico; sincrônico e diacrônico; poético e referencial; erudito e popular; acadêmico e experimental. Esta refinadíssima variação nos faz compreendê-lo e interpretá-lo como um laboratório de infinitos ensaios cujos conteúdo/forma remetem-nos à origem da palavra poesia (poíesis): criação e ao conceito aristotélico de língua como energeia: força em ação, vigor. Este ensaio, cujo aporte se inscreve no contexto desta compreensão do texto literário, apresenta o resultado de um estudo de caso sobre a compreensão da metáfora literária por adolescentes de 13 a 15 anos

Crítica do esclarecimento

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The Blume-Emery-Griffiths model at the FAD and AD interfaces

We analyse the Blume-Emery-Griffiths (BEG) model on the lattice \Zd at the ferromagnetic-antiquadrupolar-disordered (FAD) and antiquadrupolar-disordered (AD) interfaces of parameters. In our analysis of the FAD interface we introduce a Gibbs sampler of the ground states at zero temperature, and we exploit it in two different ways: first, we perform via perfect sampling an empirical evaluation of the spontaneous magnetization at zero temperature, finding a non-zero value in $d=3$ and a vanishing value in $d=2$. Second, using a careful coupling with the Bernoulli site percolation model in $d=2$, we prove rigorously that imposing $+$ boundary conditions, the magnetization in the center of a square box tends to zero in the thermodynamical limit and the two-point correlations decay exponentially. Also, using again a coupling argument, we show that the infinite volume Gibbs measure of the zero-temperature BEG exists and it is unique. In our analysis of the AD interface we restrict ourselves to $d=2$ and, by comparing the BEG model with a Bernoulli site percolation in a matching graph of $\mathbb{Z}^2$, we get a condition for the vanishing of the infinite volume limit magnetization improving, for low temperatures, earlier results obtained via expansion techniques