Optimizing Hartree-Fock orbitals by the density-matrix renormalization group

We have proposed a density-matrix renormalization group (DMRG) scheme to optimize the one-electron basis states of molecules. It improves significantly the accuracy and efficiency of the DMRG in the study of quantum chemistry or other many-fermion system with nonlocal interactions. For a water molecule, we find that the ground state energy obtained by the DMRG with only 61 optimized orbitals already reaches the accuracy of best quantum Monte Carlo calculation with 92 orbitals.Comment: published version, 4 pages, 4 figure

CsCl-type compounds in binary alloys of rare-earth metals with gold and silver

In binary alloys of silver with Sm, Tb, Ho, and Tm, and of gold with Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm, intermediate phases containing stoichiometric proportions of the two metals were found to crystallize into the CsCl (B2)-type structure. The lattice parameters of these phases are reported and a correlation has been found between these lattice parameters and the trivalent ionic radii of the rare-earth metals

Improved lattice QCD with quarks: the 2 dimensional case

QCD in two dimensions is investigated using the improved fermionic lattice Hamiltonian proposed by Luo, Chen, Xu, and Jiang. We show that the improved theory leads to a significant reduction of the finite lattice spacing errors. The quark condensate and the mass of lightest quark and anti-quark bound state in the strong coupling phase (different from t'Hooft phase) are computed. We find agreement between our results and the analytical ones in the continuum.Comment: LaTeX file (including text + 10 figures

Metric adjusted skew information: Convexity and restricted forms of superadditivity

We give a truly elementary proof of the convexity of metric adjusted skew information following an idea of Effros. We extend earlier results of weak forms of superadditivity to general metric adjusted skew informations. Recently, Luo and Zhang introduced the notion of semi-quantum states on a bipartite system and proved superadditivity of the Wigner-Yanase-Dyson skew informations for such states. We extend this result to general metric adjusted skew informations. We finally show that a recently introduced extension to parameter values $1<p\le 2$ of the WYD-information is a special case of (unbounded) metric adjusted skew information.Comment: An error in the literature is pointed ou

Quantization of Charge Carriers in Conduction Channels of Si-Based Field-Effect Transistors for Multinary Computation

The latest field-effect transistors are entering the regime where quantum effects within the conduction channel can play a significant role because of the increasingly reduced dimensions. We investigate the effects of quantized states in conduction channels in transistors with dimensions close to those presently used. We use the standard configuration of Si-based metal-oxide-semiconductor field-effect transistors (MOSFETs), as a simplified model to provide an estimate of the effect of quantization with respect to the dimensions of the conduction channel. The study shows simulated results of drain currents for various combinations of dimensions, in which distinguishable current levels as a function of the applied gate bias can be obtained at room temperature. The same qualitative dependence on dimensions is expected to apply to the state-of-the-art transistor architectures with dimensions near this range, such as fin field-effect transistors (FinFETs) and gate-all-around field-effect transistors (GAAFETs). The results show that utilizing quantized states in the conduction channel for multinary computation has become a possibility with their present dimensions.Comment: This is a revised version from our first submitted versio