423 research outputs found
Revealing treacherous points for successful light-front phenomenological applications
Light-front dynamics(LFD) plays an important role in hadron phenomenology as
evidenced from recent development of generalized parton distributions and other
quantities involving hadrons. For successful LFD applications to hadron
phenomenology, however, treacherous points such as zero-mode contributions
should be taken into account. For a concrete example of zero-mode contribution,
we present Standard Model analysis of vector anomaly in the CP-even form
factors of W^{\pm} gauge bosons. Main distinguished features of LFD is
discussed in comparison with other Hamiltonian dynamics. We also present a
power counting method to correctly pin down which hadron form factors receive
the zero-mode contribution and which ones do not. Indications from our analysis
to hadron phenomenology are discussed.Comment: 6 pages; requires espcrc2.sty; to appear in the proceedings of
Workshop on Light-Cone QCD and Nonperturbative Hadron Physics 2005 (LC 2005),
Cairns, Queensland, Australia, 7-15 Jul 200
New Developments in Treacherous Points of Light-Front Dynamics
Light-front dynamics(LFD) plays an important role in hadron phenomenology.
Last few years, however, it has been emphasized that treacherous points such as
zero-mode contributions should be taken into account for successful LFD
applications to hadron phenomenology. We discuss examples of treacherous points
and present new progresses made last few years to handle them correctly.Comment: 5 pages, espcrc1.sty. proceedings of FB XVIII (August 2006, Brazil),
to be published in Nucl. Phys.
Superconducting fluctuations and the Nernst effect: A diagrammatic approach
We calculate the contribution of superconducting fluctuations above the
critical temperature to the transverse thermoelectric response
, the quantity central to the analysis of the Nernst effect. The
calculation is carried out within the microscopic picture of BCS, and to linear
order in magnetic field. We find that as , the dominant contribution
to arises from the Aslamazov-Larkin diagrams, and is equal to the
result previously obtained from a stochastic time-dependent Ginzburg-Landau
equation [Ussishkin, Sondhi, and Huse, arXiv:cond-mat/0204484]. We present an
argument which establishes this correspondence for the heat current. Other
microscopic contributions, which generalize the Maki-Thompson and density of
states terms for the conductivity, are less divergent as .Comment: 11 pages, 5 figure
Gauge Formulation for Higher Order Gravity
This work is an application of the second order gauge theory for the Lorentz
group, where a description of the gravitational interaction is obtained which
includes derivatives of the curvature. We analyze the form of the second field
strenght, , in terms of geometrical variables. All possible
independent Lagrangians constructed with quadratic contractions of and
quadratic contractions of are analyzed. The equations of motion for a
particular Lagrangian, which is analogous to Podolsky's term of his Generalized
Electrodynamics, are calculated. The static isotropic solution in the linear
approximation was found, exhibiting the regular Newtonian behaviour at short
distances as well as a meso-large distance modification.Comment: Published versio
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