Localization of wavefunctions from extended systems using orbital occupation numbers

1992 ◽  
Vol 44 (S26) ◽  
pp. 229-241 ◽  
Author(s):  
John D. Head ◽  
Susil J. Silva
Keyword(s):  
Extended Systems ◽  
Occupation Numbers ◽  
Orbital Occupation

ELECTRONIC STRUCTURE OF YBa2(Cu1−xFex)3O7

1993 ◽  
Vol 07 (01n03) ◽  
pp. 170-173
Author(s):  
V. CRISAN ◽  
A. VERNES ◽  
V. POPESCU ◽  
L. DULCA ◽  
D. KAPUSI
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Copper Atom ◽  
Opposite Effect ◽  
Recursive Method ◽  
Electron Orbital ◽  
Occupation Numbers ◽  
Model Hamiltonian ◽  
Orbital Occupation

The density of states (DOS) at the Fermi level, (EF), for the 123 superconductor doped with iron was computed. The LCAO model hamiltonian and the Haydock recursive method were used. The iron atoms were located only in one of the copper atom positions Cu1 or Cu2 or in both of them with the same probability. The substitution of Fe in Cu1 positions increased the DOS at the Fermi level as x increased but the substitutions in the Cu2 positions had an opposite effect. In both cases the O2 and O3 positions are inequivalent. When the replacement of copper atoms is produced with the same probability in Cu1 and Cu2 positions the DOS at EF decreases as x increases. The DOS at EF and the electron orbital occupation numbers for O2 and O3 have the same behaviour as the lattice parameters, a and b.

scholarly journals Transport of pseudothermal photons through an anharmonic cavity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dmitriy S. Shapiro
Keyword(s):  
Pauli Principle ◽  
Optical Systems ◽  
Frequency Noise ◽  
Continuous Transition ◽  
Noise Current ◽  
Nonperturbative Solution ◽  
Occupation Numbers ◽  
Fundamental Reason ◽  
The Rich ◽  
Quantum Optical

AbstractUnder nonequilibrium conditions, quantum optical systems reveal unusual properties that might be distinct from those in condensed matter. The fundamental reason is that photonic eigenstates can have arbitrary occupation numbers, whereas in electronic systems these are limited by the Pauli principle. Here, we address the steady-state transport of pseudothermal photons between two waveguides connected through a cavity with Bose–Hubbard interaction between photons. One of the waveguides is subjected to a broadband incoherent pumping. We predict a continuous transition between the regimes of Lorentzian and Gaussian chaotic light emitted by the cavity. The rich variety of nonequilibrium transport regimes is revealed by the zero-frequency noise. There are three limiting cases, in which the noise-current relation is characterized by a power-law, $$S\propto J^\gamma$$ S ∝ J γ . The Lorentzian light corresponds to Breit-Wigner-like transmission and $$\gamma =2$$ γ = 2 . The Gaussian regime corresponds to many-body transport with the shot noise ($$\gamma =1$$ γ = 1 ) at large currents; at low currents, however, we find an unconventional exponent $$\gamma =3/2$$ γ = 3 / 2 indicating a nontrivial interplay between multi-photon transitions and incoherent pumping. The nonperturbative solution for photon dephasing is obtained in the framework of the Keldysh field theory and Caldeira-Leggett effective action. These findings might be relevant for experiments on photon blockade in superconducting qubits, thermal states transfer, and photon statistics probing.

scholarly journals Extended ⋁-systems and trigonometric solutions to the WDVV equations

2021 ◽  
Vol 62 (2) ◽  
pp. 022301
Author(s):  
Richard Stedman ◽  
Ian A. B. Strachan
Keyword(s):  
Wdvv Equations ◽  
Extended Systems
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