15,376 research outputs found
Nature of W51e2: Massive Cores at Different Phases of Star Formation
We present high-resolution continuum images of the W51e2 complex processed
from archival data of the Submillimeter Array (SMA) at 0.85 and 1.3 mm and the
Very Large Array (VLA) at 7 and 13 mm. We also made line images and profiles of
W51e2 for three hydrogen radio recombination lines (H26\alpha, H53\alpha, and
H66\alpha) and absorption of two molecular lines of HCN(4-3) and CO(2-1). At
least four distinct continuum components have been detected in the 3" region of
W51e2 from the SMA continuum images at 0.85 and 1.3 mm with resolutions of
0.3"x0.2" and 1.4"x0.7", respectively. The west component, W51e2-W, coincides
with the UC HII region reported from previous radio observations. The H26\alpha
line observation reveals an unresolved hyper-compact ionized core (<0.06" or
<310 AU) with a high electron temperature of 1.2x10^4 K, with corresponding
emission measure EM>7x10^{10} pc cm^{-6} and electron density N_e>7x10^6
cm^{-3}. The inferred Lyman continuum flux implies that the HII region W51e2-W
requires a newly formed massive star, an O8 star or a cluster of B-type stars,
to maintain the ionization. The east component, W51e2-E, has a total mass of
~140 M_{\sun} according to our SED analysis and a large infall rate of >
1.3x10^{-3} M_{\sun}yr^{-1} inferred from the absorption of HCN. W51e2-E
appears to be the accretion center in W51e2 and to host one or more growing
massive proto-stars. Located 2" northwest from W51e2-E, W51e2-NW is not
detected in the continuum emission at \lambda>=7 mm. Along with the maser
activities previously observed, our analysis suggests that W51e2-NW is at an
earlier phase of star formation. W51e2-N is located 2" north of W51e2-E and has
only been detected at 1.3 mm with a lower angular resolution (~1"), suggesting
that it is a primordial, massive gas clump in the W51e2 complex.Comment: 10 pages, 5 figures, 3 table, accepted for publication in Ap
Emergence of Topological and Strongly Correlated Ground States in trapped Rashba Spin-Orbit Coupled Bose Gases
We theoretically study an interacting few-body system of Rashba spin-orbit
coupled two-component Bose gases confined in a harmonic trapping potential. We
solve the interacting Hamiltonian at large Rashba coupling strengths using
Exact Diagonalization scheme, and obtain the ground state phase diagram for a
range of interatomic interactions and particle numbers. At small particle
numbers, we observe that the bosons condense to an array of topological states
with n+1/2 quantum angular momentum vortex configurations, where n = 0, 1, 2,
3... At large particle numbers, we observe two distinct regimes: at weaker
interaction strengths, we obtain ground states with topological and symmetry
properties that are consistent with mean-field theory computations; at stronger
interaction strengths, we report the emergence of strongly correlated ground
states.Comment: 14 pages, 9 figure
Implementing a neutral-atom controlled-phase gate with a single Rydberg pulse
One can implement fast two-qubit entangling gates by exploiting the Rydberg
blockade. Although various theoretical schemes have been proposed,
experimenters have not yet been able to demonstrate two-atom gates of high
fidelity due to experimental constraints. We propose a novel scheme, which only
uses a single Rydberg pulse illuminating both atoms, for the construction of
neutral-atom controlled-phase gates. In contrast to the existing schemes, our
approach is simpler to implement and requires neither individual addressing of
atoms nor adiabatic procedures. With parameters estimated based on actual
experimental scenarios, a gate fidelity higher than 0.99 is achievable.Comment: 6 pages, 5 figure
Remark on Remnant and Residue Entropy with GUP
In this article, close to the Planck scale, we discuss on the remnant and
residue entropy from a Rutz-Schwarzschild black hole in the frame of Finsler
geometry. Employing the corrected Hamilton-Jacobi equation, the tunneling
radiation of a scalar particle is presented, and the revised tunneling
temperature and revised entropy are also found. Taking into account generalized
uncertainty principle (GUP), we analyze the remnant stability and residue
entropy based on thermodynamic phase transition. In addition, the effects of
the Finsler perturbation parameter, GUP parameter and angular momentum
parameter on remnant and residual entropy are also discussed.Comment: 18 pages, 5 figures, 2 table
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