2,296,986 research outputs found
Exact Solution for Relativistic Two-Body Motion in Dilaton Gravity
We present an exact solution to the problem of the relativistic motion of 2
point masses in dimensional dilaton gravity. The motion of the bodies
is governed entirely by their mutual gravitational influence, and the spacetime
metric is likewise fully determined by their stress-energy. A Newtonian limit
exists, and there is a static gravitational potential. Our solution gives the
exact Hamiltonian to infinite order in the gravitational coupling constant.Comment: 6 pages, latex, 3 figure
Intermediate phase of the one dimensional half-filled Hubbard-Holstein model
We present a detailed numerical study of the Hubbard-Holstein model in one
dimension at half filling, including full finite-frequency quantum phonons. At
half filling, the effects of the electron-phonon and electron-electron
interactions compete, with the Holstein phonon coupling acting as an effective
negative Hubbard onsite interaction U that promotes on-site electron pairs and
a Peierls charge-density wave state. Most previous work on this model has
assumed that only Peierls or U>0 Mott insulator phases are possible at half
filling. However, there has been speculation that a third metallic phase exists
between the Peierls and Mott phases. We present results confirming the
intermediate metallic phase, and show that the Luttinger liquid correlation
exponent K_rho>1 in this region, indicating dominant superconducting pair
correlations. We explore the full phase diagram as a function of onsite Hubbard
U, phonon coupling constant, and phonon frequency.Comment: 4 pages, 4 EPS figures. v2: typos corrected. To appear in Phys. Rev.
Let
Metal matrix composite structural panel construction
Lightweight capped honeycomb stiffeners for use in fabricating metal or metal/matrix exterior structural panels on aerospace type vehicles and the process for fabricating same are disclosed. The stiffener stringers are formed in sheets, cut to the desired width and length and brazed in spaced relationship to a skin with the honeycomb material serving directly as the required lightweight stiffeners and not requiring separate metal encasement for the exposed honeycomb cells
Non-homogeneous polygonal Markov fields in the plane: graphical representations and geometry of higher order correlations
We consider polygonal Markov fields originally introduced by Arak and
Surgailis (1989). Our attention is focused on fields with nodes of order two,
which can be regarded as continuum ensembles of non-intersecting contours in
the plane, sharing a number of features with the two-dimensional Ising model.
We introduce non-homogeneous version of polygonal fields in anisotropic
enviroment. For these fields we provide a class of new graphical constructions
and random dynamics. These include a generalised dynamic representation,
generalised and defective disagreement loop dynamics as well as a generalised
contour birth and death dynamics. Next, we use these constructions as tools to
obtain new exact results on the geometry of higher order correlations of
polygonal Markov fields in their consistent regime.Comment: 54 page
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