2,000 research outputs found
Non-Kondo mechanism for resistivity minimum in spin ice conduction systems
We present a mechanism of resistivity minimum in conduction electron systems
coupled with localized moments, which is distinguished from the Kondo effect.
Instead of the spin-flip process in the Kondo effect, electrons are elastically
scattered by local spin correlations which evolve in a particular way under
geometrical frustration as decreasing temperature. This is demonstrated by the
cellular dynamical mean-field theory for a spin-ice type Kondo lattice model on
a pyrochlore lattice. Peculiar temperature dependences of the resistivity,
specific heat, and magnetic susceptibility in the non-Kondo mechanism are
compared with the experimental data in metallic Ir pyrochlore oxides.Comment: 5 pages, 3 figures, accepted for publication in Physical Review
Letter
Kaon B parameter from quenched Lattice QCD
We present results of a large-scale simulation for the Kaon B parameter
in quenched lattice QCD with the Kogut-Susskind quark action. Calculating
at 1% statistical accuracy for seven values of lattice spacing in the range
fm on lattices up to , we verify a
quadratic dependence of theoretically predicted. Strong indications
are found that, with our level of accuracy, terms
arising from our one-loop matching procedure have to be included in the
continuum extrapolation. We present (NDR, 2 GeV)=0.628(42) as our final
value, as obtained by a fit including the term.Comment: 8 pages, Latex(revtex, epsf), 2 epsf figure
Heavy-Light Decay Constants: Conclusions from the Wilson Action
We report on the results of a MILC collaboration calculation of ,
, , and their ratios. We discuss the most important
errors in more detail than we have elsewhere.Comment: LATTICE98(heavyqk) 3 latex pages and 3 postscript figures. The
perturbative correction calculated by Kuramashi has been adjusted to take
into account the fact that we match to the continuum at the kinetic mass of
the heavy meson, not the pole mass. This produces a 2 to 4 MeV change in
final results for decay constants, and has negligible effect on decay
constant ratio
Strengthening the U.S.-Japan Alliance: Pathways for Bridging Law and Policy, Columbia Law School, 2020
During the three years leading up to this year ’s 60th anniversary of the signing of the 1960 U.S.-Japan Security Treaty, a series of workshops were held under the joint sponsorship of Columbia Law School’s Center for Japanese Legal Studies and the National Defense Academy of Japan’s Center for Global Security. Bringing together experts in international law and political science primarily from the United States and Japan, the workshops examined how differing approaches to use of force and understandings of individual and collective self-defense in the two countries might adversely affect their alliance.
The workshop participants explored the underlying causes of the gap in understanding between the United States and Japan with respect to these issues, and they considered the alliance in the conte xt of each state’s interpretation of international law and policy positions regarding its rights and obligations under such law. In doing so, they also examined how the differing approaches could be applied to possible crisis situations of current concern in East Asia, and what that might mean for alliance relations
Large pion pole in Z_{S}^{MOM}/Z_{P}^{MOM} from Wilson action data
We show that, contrarily to recent claims, data from the Wilson (unimproved)
fermionic action at three different beta values demonstrate the presence of a
large Goldstone boson contribution in the quark pseudoscalar vertex,
quantitatively close to our previous estimate based on the SW action with
c_{SW}=1.769. We show that discretisation errors on Z_{S}^{MOM}/Z_{P}^{MOM}
seem to be much smaller than the Goldstone pole contribution over a very large
range of momenta. The subtraction of this non perturbative contribution leads
to numbers close to one-loop BPT.Comment: 12 pages, 5 figures, laTeX, minor corrections of typos, beta
dependence made more explicit, added one table giving the contribution of the
Goldstone vs. the discretisation errors at ap=
Lattice QCD Calculation of the Kaon B-parameter with the Wilson Quark Action
The kaon B parameter is calculated in quenched lattice QCD with the Wilson
quark action. The mixing problem of the \Delta s=2 four-quark operators is
solved non-perturbatively with full use of chiral Ward identities, and this
method enables us to construct the weak four-quark operators exhibiting good
chiral behavior. We find B_K(NDR, 2GeV)=0.562(64) in the continuum limit, which
agrees with the value obtained with the Kogut-Susskind quark action.Comment: 11 pages, latex source-file, 4 figures as ps-fil
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