56 research outputs found
Asymptotic behavior of Nambu-Bethe-Salpeter wave functions for scalar systems with a bound state
We study the asymptotic behaviors of the Nambu-Bethe-Salpeter (NBS) wave
functions, which are important for the HAL QCD potential method to extract
hadron interactions, in the case that a bound state exists in the system. We
consider the complex scalar particles, two of which lead to the formation of a
bound state. In the case of the two-body system, we show that the NBS wave
functions for the bound state as well as scattering states in the asymptotic
region behave like the wave functions in quantum mechanics, which carry the
information of the binding energy as well as the scattering phase shift. This
analysis theoretically establishes under some conditions that the HAL QCD
potential can correctly reproduce not only the scattering phase shift but also
the binding energy. As an extension of the analysis, we also study the
asymptotic behaviors of all possible NBS wave functions in the case of the
three-body systems, two of which can form a bound states.Comment: 16 pages; published versio
Phase structure and the gluon propagator of SU(2) gauge-Higgs model in two dimensions
We study numerically the phase structure and the gluon propagator of the
SU(2) gauge-Higgs model in two dimensions. First, we calculate gauge-invariant
quantities, in particular the static potential from Wilson Loop, the W
propagator, and the plaquette expectation value. Our results suggest that a
confinement-like region and a Higgs-like region appear even in two dimensions.
In the confinement-like region, the static potential rises linearly, with
string breaking at large distances, while in the Higgs-like region, it is of
Yukawa type, consistent with a Higgs-type mechanism. The correlation length
obtained from the W propagator has a finite maximum between these regions. The
plaquette expectation value shows a smooth cross-over consistent with the
Fradkin-Shenker-Osterwalder-Seiler theorem. From these results, we suggest that
there is no phase transition in two dimensions. We also calculate a
gauge-dependent order parameter in Landau gauge. Unlike gauge invariant
quantities, the gauge non-invariant order parameter has a line of discontinuity
separating these two regions. Finally we calculate the gluon propagtor. We
infer from its infrared behavior that the gluon propagator would vanish at zero
momentum in the infinite-volume limit, consistent with an analytical study.Comment: accepted in JHE
Gluon Propagators in Maximally Abelian Gauge in SU(3) Lattice QCD
In SU(3) lattice QCD, we study diagonal and off-diagonal gluon propagators in
the maximally Abelian (MA) gauge with U(1)_3 \timesU(1)_8 Landau gauge
fixing. These propagators are studied both in the coordinate space and in the
momentum space. The Monte Carlo simulation is performed on at
=6.0 and at =5.8 and 6.0 at the quenched level. In the
four-dimensional Euclidean space-time, the effective mass of diagonal gluons is
estimated as and that of
off-diagonal gluons as in the region of
fm. In the momentum space, the effective mass of diagonal gluons is
estimated as and that of
off-diagonal gluons as in the region of
GeV. The off-diagonal gluon propagator is relatively suppressed in the
infrared region and seems to be finite at zero momentum, while the diagonal
gluon propagator is enhanced. Furthermore, we also study the functional form of
these propagators in momentum space. These propagators are well fitted by
with fit parameters, and in the region of GeV. From the fit results and lattice calculations, all of the spectral
functions of diagonal and off-diagonal gluons would have negative regions.Comment: Continues and extends arXiv:1207.437
ランダウ・ゲージ固定したヤン・ミルズ理論の範囲を越えたグリボフ問題
京都大学0048新制・課程博士博士(理学)甲第18789号理博第4047号新制||理||1582(附属図書館)31740京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)准教授 菅沼 秀夫, 教授 國廣 悌二, 教授 田中 貴浩学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA
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