scholarly journals Low-energy scale excitations in the spectral function of organic monolayer systems

2012 ◽  
Vol 85 (16) ◽  
Author(s):  
J. Ziroff ◽  
S. Hame ◽  
M. Kochler ◽  
A. Bendounan ◽  
A. Schöll ◽  
...  
Keyword(s):  
Spectral Function ◽  
Energy Scale ◽  
Low Energy ◽  
Organic Monolayer

scholarly journals Low-energy scale of the periodic Anderson model

2000 ◽  
Vol 61 (19) ◽  
pp. 12799-12809 ◽  
Author(s):  
Th. Pruschke ◽  
R. Bulla ◽  
M. Jarrell
Keyword(s):  
Anderson Model ◽  
Energy Scale ◽  
Low Energy ◽  
Periodic Anderson Model

scholarly journals EXPLICITLY BROKEN LEPTON NUMBER AT LOW ENERGY IN THE HIGGS TRIPLET MODEL

2006 ◽  
Vol 21 (12) ◽  
pp. 971-977 ◽  
Author(s):  
C. A. DE S. PIRES
Keyword(s):  
Mass Spectrum ◽  
Energy Scale ◽  
Lepton Number ◽  
Low Energy ◽  
Triplet Model ◽  
Scalar Sector ◽  
Higgs Triplet Model

We assume that lepton number is explicitly broken at low energy scale (M) in the framework of the Higgs triplet (Δ) model. The scalar sector of the model is developed considering the particular assumption M = vΔ ≈ eV . We show that such assumption infers a particular mass spectrum for the scalars that compose the triplet and cause a decoupling of these scalars from those that compose the standard scalar doublet.

Energy scale of the electron-boson spectral function and superconductivity inNpPd5Al2

2010 ◽  
Vol 82 (10) ◽  
Author(s):  
G. A. Ummarino ◽  
R. Caciuffo ◽  
H. Chudo ◽  
S. Kambe
Keyword(s):  
Spectral Function ◽  
Energy Scale

scholarly journals The pseudogap in La2–xSrxCuO4: A Raman viewpoint

2000 ◽  
Vol 78 (5-6) ◽  
pp. 483-493 ◽  
Author(s):  
J G Naeini ◽  
J C Irwin ◽  
T Sasagawa ◽  
Y Togawa ◽  
K Kishio
Keyword(s):  
Fermi Surface ◽  
Normal State ◽  
Low Temperatures ◽  
Spectral Weight ◽  
Energy Scale ◽  
Low Energy ◽  
Scattering Rate ◽  
Low Energies ◽  
Consistent Picture ◽  
Rate Suppression

We report the results of Raman scattering experiments on single crystals of La2–xSrxCuO4 (La214) as a function of temperature and doping. In underdoped compounds low-energy B1g spectral weight is depleted in association with the opening of a pseudogap on regions of the Fermi surface located near (±π, 0) and (0, ±π).The magnitude of the depletion increases with decreasing doping, and in the most underdoped samples, with decreasing temperature.The spectral weight that is lost at low energies (ω [Formula: see text] 800 cm–1) is transferred to the higher energy region normally occupied by multimagnon scattering. From the normal-state B2g spectra we have determined the scattering rate Γ(ω,T) of qausiparticles located near the diagonal directions in k-space. In underdoped compounds, Γ(ω,T) is suppressed at low temperatures for energies less than Eg(x) [Formula: see text] 800 cm–1. The doping dependence of both the two-magnon scattering and the scattering rate suppression suggest that the pseudogap is characterized by an energy scale Eg ~ J, where J is the antiferromagnetic super-exchange energy. Comparison with the results from other techniques provides a consistent picture of the pseudogap in La214.PACS Nos.: 74.25.Gz, 74.72.Dn, 78.30.Er

scholarly journals SPONTANEOUS PHYSICAL COMPACTIFICATION OF THE EXTRA DIMENSIONS

2001 ◽  
Vol 16 (36) ◽  
pp. 2327-2333
Author(s):  
TIANJUN LI
Keyword(s):  
Symmetry Breaking ◽  
Extra Dimensions ◽  
High Energy ◽  
Energy Scale ◽  
Low Energy ◽  
Temperature Dependent ◽  
Supergravity Theory ◽  
Brane Model ◽  
High Energy Scale ◽  
Bulk Cosmological Constant

We conjecture that the extra dimensions are physical noncompact at high energy scale or high temperature; after the symmetry breaking or cosmological phase transition, the bulk cosmological constant may become negative, and then, the extra dimensions may become physical compact at low energy scale. We show this in a five-dimensional toy brane model with three parallel three-branes and a real bulk scalar whose potential is temperature-dependent. We also point out that after the global or gauge symmetry breaking, or the supersymmetry breaking in supergravity theory, the spontaneous physical compactification of the extra dimensions might be realized.

scholarly journals U(1)×SU(2) Gauge Theory of Underdoped Cuprate Superconductors

1998 ◽  
Vol 12 (05) ◽  
pp. 173-180 ◽  
Author(s):  
P. A. Marchetti ◽  
Zhao-Bin Su ◽  
Lu Yu
Keyword(s):  
Gauge Theory ◽  
Fermi Surface ◽  
Transport Properties ◽  
Gauge Field ◽  
Spectral Function ◽  
Normal State ◽  
Doping Concentration ◽  
Cuprate Superconductors ◽  
Low Energy ◽  
Chern Simons

The U(1)×SU(2) Chern–Simons gauge theory is applied to study the 2D t–J model describing the normal state of underdoped cuprate superconductors. The U(1) field produces a flux phase for holons converting them into Dirac-like fermions, while the SU(2) field, due to the coupling to holons gives rise to a gap for spinons. An effective low-energy action involving holons, spinons and a self-generated U(1) gauge field is derived. The Fermi surface and electron spectral function obtained are consistent with photoemission experiments. The theory predicts a minimal gap proportional to doping concentration. It also explains anomalous transport properties.

Renormalization from Density Functional Theory to Strong Coupling Models for the Electronic Structure of La2CuO4

1989 ◽  
Vol 169 ◽  
Author(s):  
Mark S. Hybertsen ◽  
Michael Schluter ◽  
E.B. Stechel ◽  
D.R. Jennison
Keyword(s):  
Electronic Structure ◽  
Hubbard Model ◽  
Strong Coupling ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Quantitative Agreement ◽  
Energy Scale ◽  
Low Energy ◽  
Energy Spectra ◽  
Functional Theory

AbstractStrong coupling models for the electronic structure of La2CuO4 are derived in two successive stages of renormalization. First, a three-band Hubbard model is derived using a constrained density functional approach. Second, exact diagonalization studies of finite clusters within the three band Hubbard model are used to select and map the low energy spectra onto effective one-band Hamiltonians. At each stage, some observables are calculated and found to be in quantitative agreement with experiment. The final results suggest the following models to be adequate descriptions of the low energy scale dynamics: (1) a spin 1/2 Heisenberg model for the insulating case with nearest neighbor J≈130 meV; (2) a "t–t'–J" model with nearly identical parameters for the electron and hole doped cases.

scholarly journals AN INFRARED ORIGIN OF LEPTONIC MIXING AND ITS TEST AT DEEPCORE

2011 ◽  
Vol 26 (27n28) ◽  
pp. 4739-4753 ◽  
Author(s):  
F. TERRANOVA
Keyword(s):  
Experimental Data ◽  
Time Scale ◽  
Energy Scale ◽  
Low Energy ◽  
Short Time Scale ◽  
Mixing Angles ◽  
Ice Cube ◽  
Energy Behavior ◽  
Current Experimental Data ◽  
Short Time

Fermion mixing is generally believed to be a low-energy manifestation of an underlying theory whose energy scale is much larger than the electroweak scale. In this paper we investigate the possibility that the parameters describing lepton mixing actually arise from the low-energy behavior of the neutrino interacting fields. In particular, we conjecture that the measured value of the mixing angles for a given process depends on the number of unobservable flavor states at the energy of the process. We provide a covariant implementation of such conjecture, draw its consequences in a two-neutrino family approximation and compare these findings with current experimental data. Finally we show that this infrared origin of mixing will be manifest at the Ice Cube DeepCore array, which measures atmospheric oscillations at energies much larger than the tau lepton mass; it will hence be experimentally tested in a short time scale.

scholarly journals Direct observation of kink evolution due to Hund’s coupling on approach to metal-insulator transition in NiS2−xSex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo Gyu Jang ◽  
Garam Han ◽  
Ina Park ◽  
Dongwook Kim ◽  
Yoon Young Koh ◽  
...  
Keyword(s):  
Direct Observation ◽  
Density Functional ◽  
Temperature Scale ◽  
Characteristic Temperature ◽  
Mean Field Theory ◽  
Mean Field ◽  
Energy Scale ◽  
Low Energy ◽  
Characteristic Energy ◽  
Angle Resolved Photoemission Spectroscopy

AbstractUnderstanding characteristic energy scales is a fundamentally important issue in the study of strongly correlated systems. In multiband systems, an energy scale is affected not only by the effective Coulomb interaction but also by the Hund’s coupling. Direct observation of such energy scale has been elusive so far in spite of extensive studies. Here, we report the observation of a kink structure in the low energy dispersion of NiS2−xSex and its characteristic evolution with x, by using angle resolved photoemission spectroscopy. Dynamical mean field theory calculation combined with density functional theory confirms that this kink originates from Hund’s coupling. We find that the abrupt deviation from the Fermi liquid behavior in the electron self-energy results in the kink feature at low energy scale and that the kink is directly related to the coherence-incoherence crossover temperature scale. Our results mark the direct observation of the evolution of the characteristic temperature scale via kink features in the spectral function, which is the hallmark of Hund’s physics in the multiorbital system.

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