2,445 research outputs found
Quark electric dipole moment induced by magnetic field
We show numerically that quarks develop an electric dipole moment in the
direction of a sufficiently intense magnetic field due to local fluctuations of
topological charge. This anomalous CP-odd effect is a spin analogue of the
Chiral Magnetic Effect in QCD.Comment: 6 pages, 4 figures, RevTex 4.0; revision: comments added, published
versio
On Dirac sheet configurations of SU(2) lattice fields
Finite temperature Euclidean SU(2) lattice gauge fields close to the
deconfinement phase transition are subjected to cooling. We find relatively
stable or absolutely stable configurations with an action below the
one-instanton action both in the deconfinement and the
confinement phases. In this paper we attempt an interpretation of these lowest
action configurations. Their action is purely magnetic and amounts to
, where () is the timelike (spacelike)
lattice size, while the topological charge vanishes. In the confined phase part
of the corresponding lattice configurations turns out to be absolutely stable
with respect to the cooling process in which case Abelian projection reveals a
homogeneous, purely Abelian magnetic field closed over the "boundary" in one of
the spatial directions. Referring to the dyonic structure established for the
confinement phase near and based on the observation made for this phase
that such events below the instanton action emerge from
dyon-antidyon annihilation, the question of stability (metastability) is
discussed for both phases. The hypothetically different dyonic structure of the
deconfinement phase, inaccessible by cooling, could explain the metastability.Comment: 14 pages, 7 figure
Chiral phase transition in lattice QCD as a metal-insulator transition
We investigate the lattice QCD Dirac operator with staggered fermions at
temperatures around the chiral phase transition. We present evidence of a
metal-insulator transition in the low lying modes of the Dirac operator around
the same temperature as the chiral phase transition. This strongly suggests the
phenomenon of Anderson localization drives the QCD vacuum to the chirally
symmetric phase in a way similar to a metal-insulator transition in a
disordered conductor. We also discuss how Anderson localization affects the
usual phenomenological treatment of phase transitions a la Ginzburg-Landau.Comment: 7 pages, 6 figures, references added, typos corrected, journal
versio
Physics of the Power Corrections in QCD
We review the physics of the power corrections to the parton model. In the
first part, we consider the power corrections which characterize the infrared
sensitivity of Feynman graphs when the contribution of short distances
dominates. The second part is devoted to the hypothetical power corrections
associated with nonperturbative effects at small distances.Comment: 35 pages, 6 figures. Lecture given by V.I.Zakharov at the Winter
School of physics of ITEP, February 1999. Minor corrections, references adde
Evidence for fine tuning of fermionic modes in lattice gluodynamics
We consider properties of zero and near-zero fermionic modes in lattice
gluodynamics. The modes are known to be sensitive to the topology of the
underlying gluonic fields in the quantum vacuum state of the gluodynamics. We
find evidence that these modes are fine tuned, that is exhibit sensitivity to
both physical (one can say, hadronic) scale and to the ultraviolet cutoff.
Namely, the density of the states is in physical units while the localization
volume of the modes tends to zero in physical units with the lattice spacing
tending to zero. We discuss briefly possible theoretical implications and also
include some general, review-type remarks.Comment: 7 pages, 7 eps figures, uses JETP Letters style (included);
substantial stylistic changes, discussions added, conclusions unchanged.
Supplementary materials and computer animations are available at
http://lattice.itep.ru/overla
A simple enzymatic assay for the quantification of C1-specific cellulose oxidation by lytic polysaccharide monooxygenases
Evidence for the Role of Instantons in Hadron Structure from Lattice QCD
Cooling is used as a filter on a set of gluon fields sampling the Wilson
action to selectively remove essentially all fluctuations of the gluon field
except for the instantons. The close agreement between quenched lattice QCD
results with cooled and uncooled configurations for vacuum correlation
functions of hadronic currents and for density-density correlation functions in
hadronic bound states provides strong evidence for the dominant role of
instantons in determining light hadron structure and quark propagation in the
QCD vacuum.Comment: 26 pages in REVTeX, plus 10 figures, uuencoded. Submitted to Physical
Review D. MIT-CTP-226
Confinement and the photon propagator in 3D compact QED: a lattice study in Landau gauge at zero and finite temperature
On the lattice we study the gauge boson propagator of three dimensional
compact QED in Landau gauge at zero and non-zero temperature. The
non-perturbative effects are taken into account by the generation of a mass, by
an anomalous dimension and by the photon wave function renormalization. All
these effects can be attributed to the monopoles: they are absent in the
propagator of the singularity-free part of the gauge field. We assess carefully
the Gribov copy problem for the propagator and the parameters emerging from the
fits.Comment: 25 pages, 32 figures, RevTeX 4; version in print in Phys. Rev. D;
typos and figures 5c and 7c correcte
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