Magnetocaloric effect in integrable spin-s chains

We study the magnetocaloric effect for the integrable antiferromagnetic high-spin chain. We present an exact computation of the Gr\"uneisen parameter, which is closely related to the magnetocaloric effect, for the quantum spin-s chain on the thermodynamical limit by means of Bethe ansatz techniques and the quantum transfer matrix approach. We have also calculated the entropy S and the isentropes in the (H,T) plane. We have been able to identify the quantum critical points H_c^{(s)}=2/(s+1/2) looking at the isentropes and/or the characteristic behaviour of the Gr\"uneisen parameter.Comment: 6 pages, 3 figure

Optical Properties of Strained Graphene

The optical conductivity of graphene strained uniaxially is studied within the Kubo-Greenwood formalism. Focusing on inter-band absorption, we analyze and quantify the breakdown of universal transparency in the visible region of the spectrum, and analytically characterize the transparency as a function of strain and polarization. Measuring transmittance as a function of incident polarization directly reflects the magnitude and direction of strain. Moreover, direction-dependent selection rules permit identification of the lattice orientation by monitoring the van-Hove transitions. These photoelastic effects in graphene can be explored towards atomically thin, broadband optical elements

Quantum mechanics on a circle: Husimi phase space distributions and semiclassical coherent state propagators

We discuss some basic tools for an analysis of one-dimensionalquantum systems defined on a cyclic coordinate space. The basic features of the generalized coherent states, the complexifier coherent states are reviewed. These states are then used to define the corresponding (quasi)densities in phase space. The properties of these generalized Husimi distributions are discussed, in particular their zeros.Furthermore, the use of the complexifier coherent states for a semiclassical analysis is demonstrated by deriving a semiclassical coherent state propagator in phase space.Comment: 29 page

O Lekton Estoico no Significante em Lacan

Esta pesquisa pretende analisar a utilização que Lacan faz no Seminário: livro 12 acerca da teoria do lekton estoico a fim de referenciar o significante como portador do desejo para o sujeito da psicanálise. Lacan afirma que foram os estoicos que levaram ao ponto de extrema perfeição a teoria do significante. Com isso, Lacan visa demonstrar que o significante operado pela psicanálise não é, exclusivamente, linguístico. Com o ressurgimento da lógica estoica no século XX, especialmente, na França, Lacan encontra no lekton estoico a possibilidade de demonstrar logicamente que a linguagem possui uma dupla via: o que é expresso em uma sentença, e a via do desejo do sujeito. Palavras-chaves: Significante; Lekton; Lacan; Linguagem; Psicanálise; Linguística

Guia de excursão pedológica do XXX Congresso Brasileiro de Ciência do Solo: solos da Zona da Mata de Pernambuco

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Quantum correlations in a few-atom spin-1 Bose-Hubbard model

We study the thermal quantum correlations and entanglement in spin-1 Bose-Hubbard model with two and three particles. While we use negativity to calculate entanglement, more general non-classical correlations are quantified using a new measure based on a necessary and sufficient condition for zero-discord state. We demonstrate that the energy level crossings in the ground state of the system are signalled by both the behavior of thermal quantum correlations and entanglement