Generic changes in United States Issini (Hemiptera, Fulgoroidea, Issidae)

Three new genera of the family Issidae are described for species formerly included in the genus Hysteropterum sensu lato: Balduza Gnezdilov and O’Brien, gen. n. (type species: Hysteropterum unum Ball 1910), Stilbometopius Gnezdilov and O’Brien, gen. n. (type species: Issus auroreus Uhler 1876), Abolloptera Gnezdilov and O’Brien, gen. n. (type species: Hysteropterum bistriatum Caldwell 1945),. The genus Tylanira Ball 1936 is redescribed. The male genitalia of Tylanira bifurca Ball 1936 is described and illustrated. Tylana ustulata Uhler 1876 is transfered to Tylanira. Hysteropterum bufo Van Duzee 1923 is transfered to Balduza gen. n. and the male genitalia of the species is described and illustrated. The subgenus Paralixes Caldwell 1945 of the genus Ulixes Stål 1861 is raised to genus – Paralixes Caldwell 1945, stat. n. A key to the issid genera of the United States is given. New data on the distribution of 7 species are given

First order dipolar phase transition in the Dicke model with infinitely coordinated frustrating interaction

We found analytically a first order quantum phase transition in the Cooper pair box array of $N$ low-capacitance Josephson junctions capacitively coupled to a resonant photon in a microwave cavity. The Hamiltonian of the system maps on the extended Dicke Hamiltonian of $N$ spins one-half with infinitely coordinated antiferromagnetic (frustrating) interaction. This interaction arises from the gauge-invariant coupling of the Josephson junctions phases to the vector potential of the resonant photon field. In $N \gg 1$ semiclassical limit, we found a critical coupling at which ground state of the system switches to the one with a net collective electric dipole moment of the Cooper pair boxes coupled to superradiant equilibrium photonic condensate. This phase transition changes from the first to second order if the frustrating interaction is switched off. A self-consistently `rotating' Holstein-Primakoff representation for the Cartesian components of the total superspin is proposed, that enables to trace both the first and the second order quantum phase transitions in the extended and standard Dicke models respectively.Comment: 12 pages, 10 figure

Isolated zeros in the spectral function as signature of a quantum continuum

We study the observable properties of quantum systems which involve a quantum continuum as a subpart. We show in a very general way that in any system, which consists of at least two isolated states coupled to a continuum, the spectral function of one of the states exhibits an isolated zero at the energy of the other state. Several examples of quantum systems exhibiting such isolated zeros are discussed. Although very general, this phenomenon can be particularly useful as an indirect detection tool for the continuum spectrum in the lab realizations of quantum critical behavior.Comment: 10 pages, 6 figures; Published versio

First coloured species of the genus Thabena Stål (Hemiptera, Fulgoroidea, Issidae) from Vietnam with general notes on the genus

A new species of the genus Thabena Stål, 1866 is described from Dalat in Vietnam. Checklist of Thabena species is given. This is the first species of the genus with multicoloured metope which may be treated as a kind of mimicry to salticid spiders. Taxonomic position of the genus Thabena within the family Issidae and its close relationships to the tribe Parahiraciini is briefly discussed

New genus and species of the tribe Parahiraciini (Hemiptera, Fulgoroidea, Issidae) from the Philippines and Vietnam

Nisoprincessa gen. n. is described for Nisoprincessa palawana sp. n. from Palawan Island of the Philippines. This represents the first record of the tribe Parahiraciini in the Philippines. Nisoprincessa palawana sp. n. is treated as two subspecies according to the length of metopial proboscis – N. palawana palawana ssp. n. and N. palawana bacuita ssp. n. Furthermore, Brevicopius gorochovi sp. n. is described from Vietnam which is the first record of the genus Brevicopius Meng, Qin et Wang, 2015 in the country

Reinhardema nov. gen., a new genus of the family Caliscelidae from Iran: (Hemiptera: Fulgoroidea)

Die neue Gattung Reinhardema gen. nov. wird für Homocnemia pasagarda Dlabola, 1982 errichtet.A new genus Reinhardema gen. nov. is erected for Homocnemia pasagarda Dlabola, 1982

Investigation of the oxohalogenide Cu4Te5O12Cl4 with weakly coupled Cu(II) tetrahedra

The crystal structure of the copper(II) tellurium(IV) oxochloride Cu$_{4}$Te$_{5}$O$_{12}$Cl$_{4}$ (Cu-45124) is composed of weakly coupled tetrahedral Cu clusters and shows crystallographic similarities with the intensively investigated compound Cu$_{2}$Te$_{2}$O$_{5}$X$_{2}$, with X~=~Cl, Br (Cu-2252). It differs from the latter by a larger separation of the tetrahedra within the crystallographic ab plane, that allows a more direct assignment of important inter-tetrahedra exchange paths and the existence of an inversion center. Magnetic susceptibility and specific heat evidence antiferromagnetic, frustrated correlations of the Cu spin moments and long range ordering with $T_{c}$=13.6 K. The entropy related to the transition is reduced due to quantum fluctuations. In Raman scattering a well structured low energy magnetic excitation is observed at energies of $\approx$50K (35cm$^{-1})$. This energy scale is reduced as compared to Cu-2252.Comment: 11 pages, 9 figures, further information see http://www.peter-lemmens.d