50 research outputs found

    A new species of Bungona in Turkey (Ephemeroptera, Baetidae): an unexpected biogeographic pattern within a pantropical complex of mayflies

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    By using an integrative approach, we describe a new species of mayfly, Bungona (Chopralla) pontica sp. n., from Turkey. The discovery of a representative of the tropical mayfly genus Bungona in the Middle East is rather unexpected. The new species shows all the main morphological characters of the subgenus Chopralla, which has its closest related species occurring in southeastern Asia. Barcoding clearly indicated that the new species represents an independent lineage isolated for a very long time from other members of the complex. The claw is equipped with two rows of three or four flattened denticles. This condition is a unique feature of Bungona (Chopralla) pontica sp. n. among West Palaearctic mayfly species. Within the subgenus Chopralla, the species can be identified by the presence of a simple, not bifid right prostheca (also present only in Bungona (Chopralla) liebenauae (Soldan, Braasch & Muu, 1987)), the shape of the labial palp, and the absence of protuberances on pronotum

    Transverse Ising Model: Markovian evolution of classical and quantum correlations under decoherence

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    The transverse Ising Model (TIM) in one dimension is the simplest model which exhibits a quantum phase transition (QPT). Quantities related to quantum information theoretic measures like entanglement, quantum discord (QD) and fidelity are known to provide signatures of QPTs. The issue is less well explored when the quantum system is subjected to decoherence due to its interaction, represented by a quantum channel, with an environment. In this paper we study the dynamics of the mutual information I(ρAB)I(\rho_{AB}), the classical correlations C(ρAB)C(\rho_{AB}) and the quantum correlations Q(ρAB)Q(\rho_{AB}), as measured by the QD, in a two-qubit state the density matrix of which is the reduced density matrix obtained from the ground state of the TIM in 1d. The time evolution brought about by system-environment interactions is assumed to be Markovian in nature and the quantum channels considered are amplitude damping, bit-flip, phase-flip and bit-phase-flip. Each quantum channel is shown to be distinguished by a specific type of dynamics. In the case of the phase-flip channel, there is a finite time interval in which the quantum correlations are larger in magnitude than the classical correlations. For this channel as well as the bit-phase-flip channel, appropriate quantities associated with the dynamics of the correlations can be derived which signal the occurrence of a QPT.Comment: 8 pages, 7 figures, revtex4-1, version accepted for publication in Eur. Phys. J.
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