8,747 research outputs found
Geometric Prequantization of the Moduli Space of the Vortex equations on a Riemann surface
The moduli space of solutions to the vortex equations on a Riemann surface
are well known to have a symplectic (in fact K\"{a}hler) structure. We show
this symplectic structure explictly and proceed to show a family of symplectic
(in fact, K\"{a}hler) structures on the moduli space,
parametrised by , a section of a line bundle on the Riemann surface.
Next we show that corresponding to these there is a family of prequantum line
bundles on the moduli space whose curvature is
proportional to the symplectic forms .Comment: 8 page
Spectroscopic Confirmation of a Protocluster at z=3.786
We present new observations of the field containing the z=3.786 protocluster,
PC217.96+32.3. We confirm that it is one of the largest and most overdense
high-redshift structures known. Such structures are rare even in the largest
cosmological simulations. We used the Mayall/MOSAIC1.1 imaging camera to image
a 1.2x0.6 deg area (~150x75 comoving Mpc) surrounding the protocluster's core
and discovered 165 candidate Lyman Alpha emitting galaxies (LAEs) and 788
candidate Lyman Break galaxies (LBGs). There are at least 2 overdense regions
traced by the LAEs, the largest of which shows an areal overdensity in its core
(i.e., within a radius of 2.5 comoving Mpc) of 14+/-7 relative to the average
LAE spatial density in the imaged field. Further, the average LAE spatial
density in the imaged field is twice that derived by other field LAE surveys.
Spectroscopy with Keck/DEIMOS yielded redshifts for 164 galaxies (79 LAEs and
85 LBGs); 65 lie at a redshift of 3.785+/-0.010. The velocity dispersion of
galaxies near the core is 350+/-40 km/s, a value robust to selection effects.
The overdensities are likely to collapse into systems with present-day masses
of >10^{15} solar masses and >6x10^{14} solar masses. The low velocity
dispersion may suggest a dynamically young protocluster. We find a weak trend
between narrow-band (Lyman Alpha) luminosity and environmental density: the
Lyman Alpha luminosity is enhanced on average by 1.35X within the protocluster
core. There is no evidence that the Lyman Alpha equivalent width depends on
environment. These suggest that star-formation and/or AGN activity is enhanced
in the higher density regions of the structure. PC217.96+32.3 is a Coma cluster
analog, witnessed in the process of formation.Comment: Accepted for publication in the Astrophysical Journal (March 27,
2016
Spin Hall effect in a Kagome lattice driven by Rashba spin-orbit interaction
Using four-terminal Landauer-B\"{u}ttiker formalism and Green's function
technique, in this present paper, we calculate numerically spin Hall
conductance (SHC) and longitudinal conductance of a finite size kagome lattice
with Rashba spin-orbit (SO) interaction both in presence and absence of
external magnetic flux in clean limit. In the absence of magnetic flux, we
observe that depending on the Fermi surface topology of the system SHC changes
its sign at different values of Fermi energy, along with the band center.
Unlike the infinite system (where SHC is a universal constant ), here SHC depends on the external parameters like SO coupling strength,
Fermi energy, etc. We show that in the presence of any arbitrary magnetic flux,
periodicity of the system is lost and the features of SHC tends to get reduced
because of elastic scattering. But again at some typical values of flux
($\phi=1/2, 1/4, 3/4..., etc.) the system retains its periodicity depending on
its size and the features of spin Hall effect (SHE) reappears. Our predicted
results may be useful in providing a deeper insight into the experimental
realization of SHE in such geometries.Comment: 10 pages, 10 figure
Magneto-transport in a mesoscopic ring with Rashba and Dresselhaus spin-orbit interactions
Electronic transport in a one-dimensional mesoscopic ring threaded by a
magnetic flux is studied in presence of Rashba and Dresselhaus spin-orbit
interactions. A completely analytical technique within a tight-binding
formalism unveils the spin-split bands in presence of the spin-orbit
interactions and leads to a method of determining the strength of the
Dresselhaus interaction. In addition to this, the persistent currents for
ordered and disordered rings have been investigated numerically. It is observed
that, the presence of the spin-orbit interaction, in general, leads to an
enhanced amplitude of the persistent current. Numerical results corroborate the
respective analytical findings.Comment: 7 pages, 7 figure
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