27,214 research outputs found
Asymptotic Learning Curve and Renormalizable Condition in Statistical Learning Theory
Bayes statistics and statistical physics have the common mathematical
structure, where the log likelihood function corresponds to the random
Hamiltonian. Recently, it was discovered that the asymptotic learning curves in
Bayes estimation are subject to a universal law, even if the log likelihood
function can not be approximated by any quadratic form. However, it is left
unknown what mathematical property ensures such a universal law. In this paper,
we define a renormalizable condition of the statistical estimation problem, and
show that, under such a condition, the asymptotic learning curves are ensured
to be subject to the universal law, even if the true distribution is
unrealizable and singular for a statistical model. Also we study a
nonrenormalizable case, in which the learning curves have the different
asymptotic behaviors from the universal law
Efficient method for simulating quantum electron dynamics under the time dependent Kohn-Sham equation
A numerical scheme for solving the time-evolution of wave functions under the
time dependent Kohn-Sham equation has been developed. Since the effective
Hamiltonian depends on the wave functions, the wave functions and the effective
Hamiltonian should evolve consistently with each other. For this purpose, a
self-consistent loop is required at every time-step for solving the
time-evolution numerically, which is computationally expensive. However, in
this paper, we develop a different approach expressing a formal solution of the
TD-KS equation, and prove that it is possible to solve the TD-KS equation
efficiently and accurately by means of a simple numerical scheme without the
use of any self-consistent loops.Comment: 5 pages, 3 figures. Physical Review E, 2002, in pres
Are Americans more Altruistic than the Japanese Comparison of Saving and Bequest Motives.
In this paper, we analyze a variety of data on saving motives, bequest motives, and bequest division from the "Comparative Survey of Savings in Japan and the United States", a binational survey conducted in 1996 by the Institute for Posts and Telecommunications Policy of the Ministry of Posts and Telecommunications of the Government of Japan, in order to shed light on which model of household behavior applies in the two countries.HOUSEHOLD ; SAVINGS ; CONSUMPTION
Phase Diagram of Spinless Fermions on an Anisotropic Triangular Lattice at Half-filling
The strong coupling phase diagram of the spinless fermions on the anisotropic
triangular lattice at half-filling is presented. The geometry of inter-site
Coulomb interactions rules the phase diagram. Unconventional charge ordered
phases are detected which are the recently reported pinball liquid and the
striped chains. Both are induced by the quantum dynamics out of classical
disordered states and afford extremely correlated metallic states and the
particular domain wall-type of excitations, respectively. The disorder once
killed by the quantum effect revives at the finite temperature, which is
discussed in the terms of the organic -ET.Comment: 4pages 6figure
Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas
We investigate single-particle excitations and strong-coupling effects in the
BCS-BEC crossover regime of a superfluid Fermi gas. Including phase and
amplitude fluctuations of the superfluid order parameter within a -matrix
theory, we calculate the superfluid density of states (DOS), as well as
single-particle spectral weight, over the entire BCS-BEC crossover region below
the superfluid transition temperature . We clarify how the pseudogap
in the normal state evolves into the superfluid gap, as one passes through
. While the pseudogap in DOS continuously evolves into the
superfluid gap in the weak-coupling BCS regime, the superfluid gap in the
crossover region is shown to appear in DOS after the pseudogap disappears below
. In the phase diagram with respect to the temperature and
interaction strength, we determine the region where strong pairing fluctuations
dominate over single-particle properties of the system. Our results would be
useful for the study of strong-coupling phenomena in the BCS-BEC crossover
regime of a superfluid Fermi gas.Comment: 22 pages, 8 figure
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