3,366 research outputs found
Variation of Entanglement Entropy in Scattering Process
In a scattering process, the final state is determined by an initial state
and an S-matrix. We focus on two-particle scattering processes and consider the
entanglement between these particles. For two types initial states; i.e., an
unentangled state and an entangled one, we calculate perturbatively the change
of entanglement entropy from the initial state to the final one. Then we show a
few examples in a field theory and in quantum mechanics.Comment: 13 pages; v2: refs. adde
Spectroscopic Observations of Several Stars Toward the Bok Globule B361
Low dispersion spectroscopic observations have been made of six of the stars toward the Bok globule B361 in order to improve the reliability of the distance to this dark cloud. Five of the six stars have been selected from Schmidt (1975) to confirm and supplement his Photometric data. The results of our MK classification of these stars reduce the uncertainty of the luminosity of the stars as well as they agree well with those by Schmidt in spectral type. Supplemented by our luminosity class estimation, Schmidt\u27s data are used to re-evaluate the distances to the stars. The resultant distance-extinction diagram indicates a more reliable distance to B361 of 400 pc
An automata characterisation for multiple context-free languages
We introduce tree stack automata as a new class of automata with storage and
identify a restricted form of tree stack automata that recognises exactly the
multiple context-free languages.Comment: This is an extended version of a paper with the same title accepted
at the 20th International Conference on Developments in Language Theory (DLT
2016
Two- and Three-Pion Interferometry for a Nonchaotic Source in Relativistic Nuclear Collisions
Two- and three-pion correlation functions are investigated for a source that
is not fully chaotic. Various models are examined to describe the source. The
chaoticity and weight factor are evaluated in each model as measures of the
strength of correlations and compared to experimental results. A new measure of
three-pion correlation is also suggested.Comment: 19 pages, 6 figure
Dispersive photoluminescence decay by geminate recombination in amorphous semiconductors
The photoluminescence decay in amorphous semiconductors is described by power
law at long times. The power-law decay of photoluminescence at
long times is commonly observed but recent experiments have revealed that the
exponent, , is smaller than the value 1.5 predicted from a
geminate recombination model assuming normal diffusion. Transient currents
observed in the time-of-flight experiments are highly dispersive characterized
by the disorder parameter smaller than 1. Geminate recombination rate
should be influenced by the dispersive transport of charge carriers. In this
paper we derive the simple relation, . Not only the
exponent but also the amplitude of the decay calculated in this study is
consistent with measured photoluminescence in a-Si:H.Comment: 18pages. Submitted for the publication in Phys. Rev.
Dispersive diffusion controlled distance dependent recombination in amorphous semiconductors
The photoluminescence in amorphous semiconductors decays according to power
law at long times. The photoluminescence is controlled by
dispersive transport of electrons. The latter is usually characterized by the
power of the transient current observed in the time-of-flight
experiments. Geminate recombination occurs by radiative tunneling which has a
distance dependence. In this paper, we formulate ways to calculate reaction
rates and survival probabilities in the case carriers execute dispersive
diffusion with long-range reactivity. The method is applied to obtain tunneling
recombination rates under dispersive diffusion. The theoretical condition of
observing the relation is obtained and theoretical
recombination rates are compared to the kinetics of observed photoluminescence
decay in the whole time range measured.Comment: To appear in Journal of Chemical Physic
Lattice Calculation of Thermal Properties of Low-Density Neutron Matter with Pionless NN Effective Field Theory
Thermal properties of low-density neutron matter are investigated by
determinantal quantum Monte Carlo lattice calculations on 3+1 dimensional cubic
lattices. Nuclear effective field theory (EFT) is applied using the pionless
single- and two-parameter neutron-neutron interactions, determined from the
scattering length and effective range. The determination of the
interactions and the calculations of neutron matter are carried out
consistently by applying EFT power counting rules. The thermodynamic limit is
taken by the method of finite-size scaling, and the continuum limit is examined
in the vanishing lattice filling limit. The pairing gap at is computed directly from the off-diagonal long-range order of the spin
pair-pair correlation function, and is found to be approximately 30% smaller
than BCS calculations with the conventional nucleon-nucleon potentials. The
critical temperature of the normal-to-superfluid phase transition and the
pairing temperature scale are determined, and the temperature-density
phase diagram is constructed. The physics of low-density neutron matter is
clearly identified as being a BCS-Bose-Einstein condensation crossover.Comment: 50 pages, 23 figures, to appear in Physical Review
Photoemission and x-ray absorption studies of valence states in (Ni,Zn,Fe,Ti)O thin films exhibiting photo-induced magnetization
By means of photoemission and x-ray absorption spectroscopy, we have studied
the electronic structure of (Ni,Zn,Fe,Ti)O thin films, which
exhibits a cluster glass behavior with a spin-freezing temperature of
K and photo-induced magnetization (PIM) below . The Ni and Zn
ions were found to be in the divalent states. Most of the Fe and Ti ions in the
thin films were trivalent (Fe) and tetravalent (Ti),
respectively. While Ti doping did not affect the valence states of the Ni and
Zn ions, a small amount of Fe ions increased with Ti concentration,
consistent with the proposed charge-transfer mechanism of PIM.Comment: 4 pages, 4 figure
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