Angle Resolved Photo-Emission Spectroscopy signature of the Resonant Excitonic State

We calculate the Angle Resolved PhotoEmission Spectroscopy (ARPES) signature of the Resonant Excitonic State (RES) that was proposed as the Pseudo-Gap state of cuprate superconductors [ArXiv 1510.03038]. This new state can be described as a set of excitonic (particle-hole) patches with an internal checkerboard modulation. Here, we modelize the RES as a charge order with $\bf{2p_{F}}$ wave vectors, where $\bf{2p_{F}}$ is the ordering vector connecting two opposite sides of the Fermi surface. We calculate the spectral weight and the density of states in the RES and we find that our model correctly reproduces the opening of the PG in Bi-2201

SU(2)-symmetry in a realistic spin-fermion model for cuprate superconductors

We consider the Pseudo-Gap (PG) state of high-$T_c$ superconductors in form of a composite order parameter fluctuating between 2$p_F$-charge ordering and superconducting (SC) pairing. In the limit of linear dispersion and at the hotspots, both order parameters are related by a SU(2) symmetry and the eight hotspot model of Efetov $\textit{et al.}$ [Nat. Phys. $\bf{9}$, 442 (2013)] is recovered. In the general case however, curvature terms of the dispersion will break this symmetry and the degeneracy between both states is lifted. Taking the full momentum dependence of the order parameter into account, we measure the strength of this SU(2) symmetry breaking over the full Brillouin zone. For realistic dispersion relations including curvature we find generically that the SU(2) symmetry breaking is small and robust to the fermiology and that the symmetric situation is restored in the large paramagnon mass and coupling limit. Comparing the level splitting for different materials we propose a scenario that could account for the competition between the PG and the SC states in the phase diagram of high-$T_c$ superconductors.Comment: 6 pages, 7 figures, published versio

AN ACCOUNT OF THE SUMATRAN BIRDS IN THE ZOOLOGICAL MUSEUM, BUITENZORG, WITH DESCRIPTIONS OF NINE NEW RACES.

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THE ARCTICTIS OF JAVA.

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The Effect of Feedback on State Narcissism

Objective: Prior research suggests that grandiose and vulnerable narcissists differ from one another in their responses to various threats—among these results is a finding suggesting individuals displaying grandiose narcissism are more likely to report negative mood states following an imaginal achievement failure, while individuals displaying vulnerable narcissism report more negative mood following an imagined romantic rejection. Further, a body of literature within the field of narcissism examines whether grandiose and vulnerable narcissism are better conceived as stable traits or as states that may fluctuate within an individual. This study sought to determine whether state grandiose and vulnerable narcissism might differ depending on the valence (enhancing or threatening) and domain (achievement or interpersonal) of manipulated feedback. Method: Participants who were led to believe they were participating in a study of “Creativity, Social Interaction, Personality, and Mood” were randomly assigned to either complete an achievement-based task (a selection of items from the Compound Remote Association Test) or an “interpersonal” activity (a game of Cyberball, played with fictitious students at other schools). After completing one of these tasks, participants completed measures of positive and negative affect, state self-esteem, and state grandiose and vulnerable narcissism. For the purpose of exploratory analyses, one week before the above manipulation participants also completed disguised measures of trait narcissism, self-esteem, and insecure adult attachment. Results: Results did not appear to support our hypotheses. State grandiose and vulnerable narcissism—and, for the most part, affect—did not vary significantly based on whether participants received enhancing or threatening feedback, nor were there significant differences based on whether that feedback was achievement-based or interpersonal. Correlational analyses showed trait grandiose narcissism was associated with higher self-esteem and better mood, while vulnerable narcissism was associated with lower self-esteem, worse mood, and an insecure attachment. It was also observed that participants higher in state grandiosity tended to score higher in state vulnerability, and vice versa. Trait narcissism scores from Part 1 were also strongly correlated with state narcissism scores collected in Part 2. Conclusions: Although other studies suggest grandiose and vulnerable individuals may differentially vary in mood following interpersonal and achievement-oriented feedback, the same phenomenon may not occur in regard to state narcissism. Possible implications and limitations of this study are discussed

SOME BIRDS OF BILLITON ISLAND

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AN ACCOUNT OF THE BORNEAN BIRDS IN THE ZOOLOGICAL MUSEUM, BUiTENZORG, WITH THE DESCRIPTION ON A NEW RACE.

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Pseudogap, charge order, and pairing density wave at the hot spots in cuprate superconductors

We address the timely issue of the presence of charge ordering at the hot-spots in the pseudo-gap phase of cuprate superconductors in the context of an emergent SU(2)-symmetry which relates the charge and pairing sectors. Performing the Hubbard-Stratonovich decoupling such that the free energy stays always real and physically meaningful we exhibit three solutions of the spin-fermion model at the hot spots. A careful examination of their stability and free energy shows that, at low temperature, the system tends towards a co-existence of charge density wave (CDW) and the composite order parameter made of diagonal quadrupolar density wave and pairing fluctuations of Ref. [Nat. Phys. $\bf{9}$, 1745 (2013)].The CDW is sensitive to the shape of the Fermi surface in contrast to the diagonal quadrupolar order, which is immune to it. SU(2) symmetry within the pseudo-gap phase also applies to the CDW state, which therefore admits a pairing density pave counterpart breaking time reversal symmetry.Comment: 15 pages, 15 figures, final version + typo corrected in Eq. (12

Charge orders, magnetism and pairings in the cuprate superconductors

We review the recent developments in the field of cuprate superconductors with the special focus on the recently observed charge order in the underdoped compounds. We introduce new theoretical developments following the study of the antiferromagnetic (AF) quantum critical point (QCP) in two dimensions, in which preemptive orders in the charge and superconducting (SC) sectors emerged, that are in turn related by an SU(2) symmetry. We consider the implications of this proliferation of orders in the underdoped region, and provide a study of the type of fluctuations which characterize the SU(2) symmetry. We identify an intermediate energy scale where the SU(2) pairing fluctuations are dominant and argue that they are unstable towards the formation of a Resonant Peierls Excitonic (RPE) state at the pseudogap (PG) temperature $T^{*}$. We discuss the implications of this scenario for a few key experiments.Comment: 16 pages, 17 figure

η\eta collective mode as A1g_{1g} Raman resonance in cuprate superconductors

We discuss the possible existence a spin singlet excitation with charge $\pm2$ ($\eta$-mode) originating the $A_{1g}$ Raman resonance in cuprate superconductors. This $\eta$-mode relates the $d$-wave superconducting singlet pairing channel to a $d$-wave charge channel. We show that the $\eta$ boson forms a particle-particle bound state below the $2\Delta$ threshold of the particle-hole continuum where $\Delta$ is the maximum $d$-wave gap. Within a generalized random phase approximation and Bethe-Salpether approximation study, we find that this mode has energies similar to the resonance observed by Inelastic Neutron Scattering (INS) below the superconducting (SC) coherent peak at $2\Delta$ in various SC cuprates compounds. We show that it is a very good candidate for the resonance observed in Raman scattering below the $2\Delta$ peak in the $A_{1g}$ symmetry. Since the $\eta$-mode sits in the $S=0$ channel, it may be observable via Raman, X -ray or Electron Energy Loss Spectroscopy probes