1,358 research outputs found
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 wave
vectors, where 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- superconductors in form
of a composite order parameter fluctuating between 2-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 [Nat. Phys. , 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- 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.
abstract not availabl
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 threatsâamong 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 âCreativity, Social Interaction, Personality, and Moodâ were randomly assigned to either complete an achievement-based task (a selection of items from the Compound Remote Association Test) or an âinterpersonalâ 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 narcissismâand, for the most part, affectâdid 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. , 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 . We discuss the
implications of this scenario for a few key experiments.Comment: 16 pages, 17 figure
collective mode as A Raman resonance in cuprate superconductors
We discuss the possible existence a spin singlet excitation with charge
(-mode) originating the Raman resonance in cuprate
superconductors. This -mode relates the -wave superconducting singlet
pairing channel to a -wave charge channel. We show that the boson
forms a particle-particle bound state below the threshold of the
particle-hole continuum where is the maximum -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 in various SC cuprates compounds. We show that it is a very good
candidate for the resonance observed in Raman scattering below the
peak in the symmetry. Since the -mode sits in the channel,
it may be observable via Raman, X -ray or Electron Energy Loss Spectroscopy
probes
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