1,500 research outputs found
Chirality violating condensates in QCD and their connection with zero mode solutions of quark Dirac equations
It is demonstrated, that chirality violating condensates in massless QCD
arise entirely from zero mode solutions of Dirac equations in arbitrary gluon
fields. The model is suggested, where the zero mode solutions are the ones for
quarks, moving in the instanton field. Basing on this model were calculated the
quark condensate magnetic susceptibilities of dimensions and 5
( and ). The good considence of the values and
, obtained in this approach with ones, found from the hadronic spectrum ia
a serious argument in favour, that instantons are the only source of chirality
violating condensates in QCD. The temperature dependence of the quark
condensate is discussed. It is shown that the phase transition, corresponding
to the -dependence of the quark condensate as an order
parameter, is of the type of crossover.Comment: The talk presented of Gribov-80 Workshop, May 28-30, 2010, Trieste, 8
pages, minor change
Spontaneous violation of chiral symmetry in QCD vacuum is the origin of baryon masses and determines baryon magnetic moments and their other static properties
A short review is presented of the spontaneous violation of chiral symmetry
in QCD vacuum. It is demonstrated, that this phenomenon is the origin of baryon
masses in QCD. The value of nucleon mass is calculated as well as the masses of
hyperons and some baryonic resonances and expressed mainly through the values
of quark condensates -- -- the vacuum
expectation values (v.e.v.) of quark field. The concept of vacuum expectation
values induced by external fields is introduced. It is demonstrated that such
v.e.v. induced by static electromagnetic field results in quark condensate
magnetic susceptibility, which plays the main role in determination of baryon
magnetic moments. The magnetic moments of proton, neutron and hyperons are
calculated. The results of calculation of baryon octet -decay constants
are also presented.Comment: 13 pades, 5 figures. Dedicated to 85-birthday of acad. S.T.Belyaev.
To be published in Phys.At.Nucl. Few references are correcte
Necessary and sufficient condition on global optimality without convexity and second order differentiability
The main goal of this paper is to give a necessary and sufficient condition
of global optimality for unconstrained optimization problems, when the objective
function is not necessarily convex. We use Gâteaux differentiability of the objective
function and its bidual (the latter is known from convex analysis)
Metal-insulator transition in hydrogenated graphene as manifestation of quasiparticle spectrum rearrangement of anomalous type
We demonstrate that the spectrum rearrangement can be considered as a
precursor of the metal-insulator transition observed in graphene dosed with
hydrogen atoms. The Anderson-type transition is attributed to the coincidence
between the Fermi level and the mobility edge, which appearance is induced by
the spectrum rearrangement. Available experimental data are thoroughly compared
to the theoretical results for the Lifshitz impurity model
The structure functions of longitudinal virtual photon at low virtualities
The structure functions of longitudinal virtual photon at low virtualities
are calculated in the framework of chiral pertubation theory(ChPT) in the zero
and first order of ChPT. It is assumed that the virtuality of target
longitudinal photon is much less than the virtuality of the hard projectile
photon and both are less than the characteristic ChPT scale.Comment: 16 pages, 8 figure
Experimental demonstration of Aharonov-Casher interference in a Josephson junction circuit
A neutral quantum particle with magnetic moment encircling a static electric
charge acquires a quantum mechanical phase (Aharonov-Casher effect). In
superconducting electronics the neutral particle becomes a fluxon that moves
around superconducting islands connected by Josephson junctions. The full
understanding of this effect in systems of many junctions is crucial for the
design of novel quantum circuits. Here we present measurements and quantitative
analysis of fluxon interference patterns in a six Josephson junction chain. In
this multi-junction circuit the fluxon can encircle any combination of charges
on five superconducting islands, resulting in a complex pattern. We compare the
experimental results with predictions of a simplified model that treats fluxons
as independent excitations and with the results of the full diagonalization of
the quantum problem. Our results demonstrate the accuracy of the fluxon
interference description and the quantum coherence of these arrays
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