175 research outputs found
Hypercommutative operad as a homotopy quotient of BV
We give an explicit formula for a quasi-isomorphism between the operads
Hycomm (the homology of the moduli space of stable genus 0 curves) and
BV/ (the homotopy quotient of Batalin-Vilkovisky operad by the
BV-operator). In other words we derive an equivalence of Hycomm-algebras and
BV-algebras enhanced with a homotopy that trivializes the BV-operator.
These formulas are given in terms of the Givental graphs, and are proved in
two different ways. One proof uses the Givental group action, and the other
proof goes through a chain of explicit formulas on resolutions of Hycomm and
BV. The second approach gives, in particular, a homological explanation of the
Givental group action on Hycomm-algebras.Comment: minor corrections added, to appear in Comm.Math.Phy
Jet multiplicities as the QGP thermometer
It is proposed to use the energy behavior of mean multiplicities of jets
propagating in a nuclear medium as the thermometer of this medium during the
collision phases. The qualitative effects are demonstrated in the framework of
the fixed coupling QCD with account of jet quenching.Comment: Modify version of hep-ph/0509344, 3 figure
Hybrid heterostructures with superconducting/antiferromagnetic interfaces
We report on structural, DC, X-ray and neutron studies of hybrid
superconducting mesa-heterostructures with a cuprate antiferromagnetic
interlayer Ca1-xSrxCuO2 (CSCO). The upper electrode was bilayer Nb/Au
superconductor and copper oxide superconductor YBa2Cu3O7 (YBCO) was the bottom
electrode. It was experimentally shown that during the epitaxial growth of the
two films YBCO and CSCO a charge carrier doping takes place in the CSCO
interlayer with a depth about 20 nm. The conductivity of the doped part of CSCO
layer is close to the metal type, while the reference CSCO film, deposited
directly on NdGaO3 substrate, behaves as Mott insulator with the hopping
conductivity. The interface Au/CSCO is clearly seen on bright-field image of
the cross-section of heterostructure and gives the main contribution to the
total resistance of mesa-heterostructure.Comment: 16 pages, 9 figure
Normal state properties of high angle grain boundaries in (Y,Ca)Ba2Cu3O7-delta
By lithographically fabricating an optimised Wheatstone bridge geometry, we
have been able to make accurate measurements of the resistance of grain
boundaries in Y1-xCaxBa2Cu3O7-d between the superconducting transition
temperature, Tc, and room temperature. Below Tc the normal state properties
were assessed by applying sufficiently high currents. The behaviour of the
grain boundary resistance versus temperature and of the conductance versus
voltage are discussed in the framework charge transport through a tunnel
barrier. The influence of misorientation angle, oxygen content, and calcium
doping on the normal state properties is related to changes of the height and
shape of the grain boundary potential barrier.Comment: 17 pages, 1 table, 5 figures, submitted to PR
On bi-Hamiltonian deformations of exact pencils of hydrodynamic type
In this paper we are interested in non trivial bi-Hamiltonian deformations of
the Poisson pencil \omega_{\lambda}=\omega_2+\lambda
\omega_1=u\delta'(x-y)+\f{1}{2}u_x\delta(x-y)+\lambda\delta'(x-y).
Deformations are generated by a sequence of vector fields ,
where each is homogenous of degree with respect to a grading
induced by rescaling. Constructing recursively the vector fields one
obtains two types of relations involving their unknown coefficients: one set of
linear relations and an other one which involves quadratic relations. We prove
that the set of linear relations has a geometric meaning: using
Miura-quasitriviality the set of linear relations expresses the tangency of the
vector fields to the symplectic leaves of and this tangency
condition is equivalent to the exactness of the pencil .
Moreover, extending the results of [17], we construct the non trivial
deformations of the Poisson pencil , up to the eighth order
in the deformation parameter, showing therefore that deformations are
unobstructed and that both Poisson structures are polynomial in the derivatives
of up to that order.Comment: 34 pages, revised version. Proof of Theorem 16 completely rewritten
due to an error in the first versio
Coupling of the lattice and superlattice deformations and hysteresis in thermal expansion for the quasi one-dimensional conductor TaS
An original interferometer-based setup for measurements of length of
needle-like samples is developed, and thermal expansion of o-TaS crystals
is studied. Below the Peierls transition the temperature hysteresis of length
is observed, the width of the hysteresis loop being up to . The behavior of the loop is anomalous: the length changes so
that it is in front of its equilibrium value. The hysteresis loop couples with
that of conductivity. The sign and the value of the length hysteresis are
consistent with the strain dependence of the charge-density waves (CDW) wave
vector. With lowering temperature down to 100 K the CDW elastic modulus grows
achieving a value comparable with the lattice Young modulus. Our results could
be helpful in consideration of different systems with intrinsic
superstructures.Comment: 4 pages, 3 figures. Phys. Rev. Lett., accepted for publicatio
The Problem of Quality Improvement Search Queries
Π ΡΡΠ°ΡΡΠ΅ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΊΠ°ΡΠ΅ΡΡΠ²Π° ΠΏΠΎΠΈΡΠΊΠΎΠ²ΡΡ
Π·Π°ΠΏΡΠΎΡΠΎΠ² ΡΡΡΠ΄Π΅Π½ΡΠΎΠ². ΠΠ½Π°Π»ΠΈΠ· ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
Π΄Π°Π½Π½ΡΡ
ΠΏΠΎΠΊΠ°Π·Π°Π» Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ ΠΏΠΎΠΈΡΠΊΠΎΠ²ΡΡ
Π·Π°ΠΏΡΠΎΡΠΎΠ². Π ΡΠ°ΠΌΠΊΠ°Ρ
ΡΠ°Π±ΠΎΡΡ Π±ΡΠ»ΠΈ ΠΎΠ±ΡΠ°Π±ΠΎΡΠ°Π½Ρ ΠΈ ΡΠ΅ΡΡΡΡΠΊΡΡΡΠΈΡΠΎΠ²Π°Π½Ρ Π°Π»Π³ΠΎΡΠΈΡΠΌΡ ΠΏΠΎΡΡΡΠΎΠ΅Π½ΠΈΡ Π·Π°ΠΏΡΠΎΡΠΎΠ² Π² ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΠΏΠΎΠΈΡΠΊΠΎΠ²ΡΡ
ΡΠΈΡΡΠ΅ΠΌΠ°Ρ
, ΡΡΠΎ ΠΏΡΠΈΠ²Π΅Π»ΠΎ ΠΊ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΡ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΡΠΎΡΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΊΠΎΡΡΠ΅ΠΊΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠΈΡΠΊΠΎΠ²ΠΎΠ³ΠΎ Π·Π°ΠΏΡΠΎΡΠ° ΠΈ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΡ ΠΊΠ°ΡΠ΅ΡΡΠ²Π° ΠΏΠΎΠ»ΡΡΠ°Π΅ΠΌΠΎΠΉ ΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΌ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ. ΠΡΠΈ ΡΠΎΡΡΠ°Π²Π»Π΅Π½ΠΈΠΈ ΡΠΊΠ°Π·Π°Π½Π½ΡΡ
Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² ΠΏΡΠΈΠΌΠ΅Π½ΡΠ»ΠΈΡΡ ΠΎΡΠ³ΡΠ°ΡΡ ΠΈ Π°Π»Π³ΠΎΡΠΈΡΠΌ ΠΠ΅ΠΉΠΊΡΡΡΡ.The article presents the results of a study of the quality of students' search queries. Analysis of the data obtained showed the need to optimize search queries. As part of the work, the algorithms for constructing queries in various search engines were processed and restructured, which led to a reduction in the time for compiling a correct search query and an increase in the quality of information received by the user. Digraphs and Dijkstra's algorithm were used in the compilation of these algorithms
Optimization of Search Queries from the Point of View of Environmental Problems
Π Π΄Π°Π½Π½ΠΎΠΉ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΡΠΊΠΎΠΉ ΡΠ°Π±ΠΎΡΠ΅ Π±ΡΠ» ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½ ΡΠ΅Π·ΠΈΡ ΠΎ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠΈ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΠΈ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΠΈ ΡΠ΅ΡΡΡΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΡΠ΅Π±Π»Π΅Π½ΠΈΡ Π·Π° ΡΡΠ΅Ρ ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ ΠΏΠΎΠΈΡΠΊΠ° ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ. ΠΠ²ΡΠΎΡΠ°ΠΌΠΈ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠ°Π½ ΠΏΠ»Π°Π³ΠΈΠ½, Π²ΡΡΡΠ°ΠΈΠ²Π°Π΅ΠΌΡΠΉ Π² ΠΏΠΎΠΈΡΠΊΠΎΠ²ΡΡ ΡΠΈΡΡΠ΅ΠΌΡ, ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡΠΈΠΉ ΡΡΠΊΠΎΡΠΈΡΡ ΠΏΠΎΠΈΡΠΊ. ΠΠ°Π½Π½Π°Ρ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ° ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΡΠΎΠΊΡΠ°ΡΠ΅Π½ΠΈΡ Π·Π°ΡΡΠ°ΡΠΈΠ²Π°Π΅ΠΌΠΎΠΉ ΠΊΠΎΠΌΠΏΡΡΡΠ΅ΡΠ½ΡΠΌ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΡΠ»Π΅ΠΊΡΡΠΎΡΠ½Π΅ΡΠ³ΠΈΠΈ, ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ Π²ΡΠ±ΡΠΎΡΠ° ΡΠ³Π»Π΅ΡΠΎΠ΄Π° Π² Π°ΡΠΌΠΎΡΡΠ΅ΡΡ, Π° Π·Π½Π°ΡΠΈΡ, ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΡ Π²ΡΠ΅Π΄Π° ΠΎΠΊΡΡΠΆΠ°ΡΡΠ΅ΠΉ ΡΡΠ΅Π΄Π΅.In this research paper, the thesis was considered about the possibility of saving time and reducing resource consumption by optimizing the search for information. The authors have developed a plugin embedded in the search engine, which allows you to speed up the search. This development leads to a reduction in the electricity consumed by computer equipment, a reduction in carbon emissions into the atmosphere, and therefore a reduction in environmental harm
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