7,364 research outputs found
A few remarks on the zero modes of the Faddeev-Popov operator in the Landau and maximal Abelian gauges
The construction outlined by Henyey is employed to provide examples of
normalizable zero modes of the Faddeev-Popov operator in the Landau and maximal
Abelian gauges in SU(2) Euclidean Yang-Mills theories in d=3 dimensions. The
corresponding gauge configurations have all finite norm ||A||^2 < \infty. In
particular, in the case of the Landau gauge, the explicit construction of an
infinite class of normalizable zero modes with finite norm ||A||^2 is provided.Comment: 9 pages. Extended discussion in the conclusions. Version accepted for
publication in the J. Math. Phy
Pad\'e approximation and glueball mass estimates in 3d and 4d with N_c = 2,3 colors
A Pad\'e approximation approach, rooted in an infrared moment technique, is
employed to provide mass estimates for various glueball states in pure gauge
theories. The main input in this analysis are theoretically well-motivated fits
to lattice gluon propagator data, which are by now available for both SU(2) and
SU(3) in 3 and 4 space-time dimensions. We construct appropriate gauge
invariant and Lorentz covariant operators in the (pseudo)scalar and
(pseudo)tensor sector. Our estimates compare reasonably well with a variety of
lattice sources directly aimed at extracting glueball masses.Comment: 11 pages, 5 .png figures. v2: extra figure, calculational details and
references; improved presentation and title. Version to appear in Phys.Lett.
Long-distance radiative coupling between quantum dots in photonic crystal dimers
We study the mutual interaction between two identical quantum dots coupled to
the normal modes of two-site photonic crystal molecules in a planar waveguide
geometry, i.e. photonic crystal dimers. We find that the radiative coupling
between the two quantum emitters is maximized when they are in resonance with
either the bonding or the antibonding modes of the coupled cavity system.
Moreover, we find that such effective interdot coupling is sizable, in the meV
range, and almost independent from the cavities distance, as long as a normal
mode splitting exceeding the radiative linewidth can be established (strong
cavity-cavity coupling condition). In realistic and high quality factor
photonic crystal cavity devices, such distance can largely exceed the emission
wavelength, which is promising for long distance entanglement generation
between two qubits in an integrated nanophotonic platform. We show that these
results are robust against position disorder of the two quantum emitters within
their respective cavities.Comment: 10 pages, 6 figure
Dual approaches for defects condensation
We review two methods used to approach the condensation of defects
phenomenon. Analyzing in details their structure, we show that in the limit
where the defects proliferate until occupy the whole space these two methods
are dual equivalent prescriptions to obtain an effective theory for the phase
where the defects (like monopoles or vortices) are completely condensed,
starting from the fundamental theory defined in the normal phase where the
defects are diluted.Comment: 7 pages, major modifications. Version accepted for publication in
Physics Letters
Accessing the topological susceptibility via the Gribov horizon
The topological susceptibility, , following the work of Witten and
Veneziano, plays a key role in identifying the relative magnitude of the
mass, the so-called problem. A nonzero is
caused by the Veneziano ghost, the occurrence of an unphysical massless pole in
the correlation function of the topological current. In a recent paper
(Phys.Rev.Lett.114 (2015) 24, 242001), an explicit relationship between this
Veneziano ghost and color confinement was proposed, by connecting the dynamics
of the Veneziano ghost, and thus the topological susceptibility, with Gribov
copies. However, the analysis is incompatible with BRST symmetry (Phys.Rev.D 93
(2016) no.8, 085010). In this paper, we investigate the topological
susceptibility, , in SU(3) and SU(2) Euclidean Yang-Mills theory using
an appropriate Pad\'e approximation tool and a non-perturbative gluon
propagator, within a BRST invariant framework and by taking into account Gribov
copies in a general linear covariant gauge.Comment: 17 pages, 4 figures. v2: corrected typos, new figures, improved style
of presentatio
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