Key technologies for 10 Gb/s optical fiber transmission systems

Nishimoto, Hiroshi; Chikama, T.; Kuwahara, H.

doi:10.1109/icct.1996.545130

Cited by 3 publications

(5 citation statements)

References 6 publications

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“…[69][70][71] DFTB, like other DFT approaches based on local xc-functionals, shows difficulties in the description of the zwitterionic state where long-range charge-charge interactions play an important role. In a recent study Nishimoto et al72 found that the DFTB self-consistency cycle failed to converge for the model peptides chignolin (PDB ID: 1UAO 73 ) and Trp-cage (PDB ID: 1L2Y 74 ) in the zwitterionic conformation. It has been, however, shown both theoretically with force-field based molecular dynamics and experimentally using The SCF convergence plot of chignolin and Trp-cage proteins as a function of rangeseparation parameter ω for the LC-DFTB method.…”

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confidence: 99%

Implementation and benchmark of a long-range corrected functional in the density functional based tight-binding method

Lutsker

Aradi

Niehaus

2015

The Journal of Chemical Physics

147

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Bridging the gap between first principles methods and empirical schemes, the density functional based tight-binding method (DFTB) has become a versatile tool in predictive atomistic simulations over the past years. One of the major restrictions of this method is the limitation to local or gradient corrected exchange-correlation functionals. This excludes the important class of hybrid or long-range corrected functionals, which are advantageous in thermochemistry, as well as in the computation of vibrational, photoelectron, and optical spectra. The present work provides a detailed account of the implementation of DFTB for a long-range corrected functional in generalized Kohn-Sham theory. We apply the method to a set of organic molecules and compare ionization potentials and electron affinities with the original DFTB method and higher level theory. The new scheme cures the significant overpolarization in electric fields found for local DFTB, which parallels the functional dependence in first principles density functional theory (DFT). At the same time, the computational savings with respect to full DFT calculations are not compromised as evidenced by numerical benchmark data.

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confidence: 99%

Implementation and benchmark of a long-range corrected functional in the density functional based tight-binding method

Lutsker

Aradi

Niehaus

2015

The Journal of Chemical Physics

147

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“…Again, the RDA reproduces the weak-coupling expression very well, and also provides a reasonable descrip- [18], the DDMRG for an insulating solution (filled triangles) [19], QMC (stars) [17,20], weak-coupling perturbation theory [Eq. (19)] (solid line) [15], and strong-coupling theory [Eq. (21)] (dotted line) [17].…”

Section: Energy and Double Occupancymentioning

confidence: 90%

“…In Fig. 4, we also compare the extrapolated RDA results as a function of the interaction strength U/t with those from Quantum Monte-Carlo (QMC) [17,20], the Dynamical Density-Matrix Renormalization Group method (DDMRG) [18,19], weak-coupling perturbation theory, see Eq. (18) [15], and strong-coupling perturbation theory, see Eq.…”

Section: Energy and Double Occupancymentioning

confidence: 99%

“…4. Extrapolated data for the ground-state energy as a function of the interaction strength in the RDA (circles), the DDMRG for a metallic solution (open triangles) [18], the DDMRG for an insulating solution (filled triangles) [19], QMC (stars) [17,20], weak-coupling perturbation theory [Eq. ( 18)] (solid line) [15], and strong-coupling perturbation theory [Eq.…”

Section: Energy and Double Occupancymentioning

confidence: 99%

“…We show the resulting data for the double occupancy in Fig. 6, where we compare our results with those from QMC [17,20], the DDMRG [18,19], weak-coupling perturbation theory, see Eq. ( 19) [15], and strong-coupling perturbation theory, see Eq.…”

Section: Energy and Double Occupancymentioning

confidence: 99%

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Random dispersion approximation for the Hubbard model

Gebhard

Noack

2008

Eur. Phys. J. B

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We use the Random Dispersion Approximation (RDA) to study the Mott-Hubbard transition in the Hubbard model at half band filling. The RDA becomes exact for the Hubbard model in infinite dimensions. We implement the RDA on finite chains and employ the Lanczos exact diagonalization method in real space to calculate the ground-state energy, the average double occupancy, the charge gap, the momentum distribution, and the quasi-particle weight. We find a satisfactory agreement with perturbative results in the weak-and strong-coupling limits. A straightforward extrapolation of the RDA data for L ≤ 14 lattice results in a continuous Mott-Hubbard transition at Uc ≈ W . We discuss the significance of a possible signature of a coexistence region between insulating and metallic ground states in the RDA that would correspond to the scenario of a discontinuous Mott-Hubbard transition as found in numerical investigations of the Dynamical Mean-Field Theory for the Hubbard model. PACS. 71.10Fd Lattice fermion models (Hubbard model, etc.) -71.27.+a Strongly correlated electron systems; heavy fermions -71.30+h Metal-insulator transitions and other electronic transitions

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Use of dispersion managed fibers in parallel WDM systems

Segatto

Taylor²,

Kashyap³

1999 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference

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Key technologies for 10 Gb/s optical fiber transmission systems

Cited by 3 publications

References 6 publications

Implementation and benchmark of a long-range corrected functional in the density functional based tight-binding method

Implementation and benchmark of a long-range corrected functional in the density functional based tight-binding method

Random dispersion approximation for the Hubbard model

Use of dispersion managed fibers in parallel WDM systems

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