1,903 research outputs found
Towards Integrability of Topological Strings I: Three-forms on Calabi-Yau manifolds
The precise relation between Kodaira-Spencer path integral and a particular
wave function in seven dimensional quadratic field theory is established. The
special properties of three-forms in 6d, as well as Hitchin's action
functional, play an important role. The latter defines a quantum field theory
similar to Polyakov's formulation of 2d gravity; the curious analogy with
world-sheet action of bosonic string is also pointed out.Comment: 31 page
Non-autonomous Hamiltonian systems related to highest Hitchin integrals
We describe non-autonomous Hamiltonian systems coming from the Hitchin
integrable systems. The Hitchin integrals of motion depend on the W-structures
of the basic curve. The parameters of the W-structures play the role of times.
In particular, the quadratic integrals dependent on the complex structure
(W_2-structure) of the basic curve and times are coordinate on the Teichmuller
space. The corresponding flows are the monodromy preserving equations such as
the Schlesinger equations, the Painleve VI equation and their generalizations.
The equations corresponding to the highest integrals are monodromy preserving
conditions with respect to changing of the W_k-structures (k>2). They are
derived by the symplectic reduction from the gauge field theory on the basic
curve interacting with W_k-gravity. As by product we obtain the classical Ward
identities in this theory.Comment: 21 pages,Latex, Contribution in the Proceedings "International
Seminar on Integrable systems". In memoriam Mikail V. Saveliev. Bonn,
February, 199
Quantum matter wave dynamics with moving mirrors
When a stationary reflecting wall acting as a perfect mirror for an atomic
beam with well defined incident velocity is suddenly removed, the density
profile develops during the time evolution an oscillatory pattern known as
diffraction in time. The interference fringes are suppressed or their
visibility is diminished by several effects such as averaging over a
distribution of incident velocities, apodization of the aperture function,
atom-atom interactions, imperfect reflection or environmental noise. However,
when the mirror moves with finite velocity along the direction of propagation
of the beam, the visibility of the fringes is enhanced. For mirror velocities
below beam velocity, as used for slowing down the beam, the matter wave splits
into three regions separated by space-time points with classical analogues. For
mirror velocities above beam velocity a visibility enhancement occurs without a
classical counterpart. When the velocity of the beam approaches that of the
mirror the density oscillations rise by a factor 1.8 over the stationary value.Comment: 5.2 pages, 6 figure
Proton structure corrections to electronic and muonic hydrogen hyperfine splitting
We present a precise determination of the polarizability and other proton
structure dependent contributions to the hydrogen hyperfine splitting, based
heavily on the most recent published data on proton spin dependent structure
functions from the EG1 experiment at the Jefferson Laboratory. As a result, the
total calculated hyperfine splitting now has a standard deviation slightly
under 1 part-per-million, and is about 1 standard deviation away from the
measured value. We also present results for muonic hydrogen hyperfine
splitting, taking care to ensure the compatibility of the recoil and
polarizability terms.Comment: 9 pages, 1 figur
Rational symplectic coordinates on the space of Fuchs equations -case
A method of constructing of Darboux coordinates on a space that is a
symplectic reduction with respect to a diagonal action of GL(m}) on a
Cartesian product of orbits of coadjoint representation of is
presented. The method gives an explicit symplectic birational isomorphism
between the reduced space on the one hand and a Cartesian product of
coadjoint orbits of dimension on an orbit of dimension on
the other hand. In a generic case of the diagonalizable matrices it gives just
the isomorphism that is birational and symplectic between some open, in a
Zariski topology, domain of the reduced space and the Cartesian product of the
orbits in question. The method is based on a Gauss decomposition of a matrix on
a product of upper-triangular, lower-triangular and diagonal matrices. It works
uniformly for the orbits formed by diagonalizable or not-diagonalizable
matrices. It is elaborated for the orbits of maximal dimension that is
.Comment: 11 page
Cartridge toolholders and boring heads for high-precision holes treatment
The analysis of cartridge tool holders and boring heads constructions was done, the constructions of micrometer adjustment of blades were considered, models and results of stress, displacement and safety factor for split bushing are shown
Design Features of Instruments in Automated Production Facilities
The article deals with designing cutting tools in automated production facilities and with their main features – interchangeability, versatility, high accuracy
- …