12,669 research outputs found
Entanglement and quantum superposition induced by a single photon
We predict the occurrence of single-photon-induced entanglement and quantum
superposition in a hybrid quantum model, introducing an optomechanical coupling
into the Rabi model. Originally, it comes from the photon-dependent quantum
property of ground state featured by the proposed hybrid model. It associates
with a single-photon-induced quantum phase transition, and is immune to the
term of the spin-field interaction. Moreover, the obtained quantum
superposition state is actual a squeezed cat state, which can give a
significant precision enhancement in quantum metrology. This work offers an
approach to manipulate entanglement and quantum superposition with a single
photon, which might has potential applications in the engineering of new
single-photon quantum devices, and also fundamentally broaden the regime of
cavity QED.Comment: 7 pages, 5 figures, Published in Physical Review A 97, 033807 (2018).
arXiv admin note: text overlap with arXiv:1803.0659
Multi-view Point Cloud Registration with Adaptive Convergence Threshold and its Application on 3D Model Retrieval
Multi-view point cloud registration is a hot topic in the communities of
multimedia technology and artificial intelligence (AI). In this paper, we
propose a framework to reconstruct the 3D models by the multi-view point cloud
registration algorithm with adaptive convergence threshold, and subsequently
apply it to 3D model retrieval. The iterative closest point (ICP) algorithm is
implemented combining with the motion average algorithm for the registration of
multi-view point clouds. After the registration process, we design applications
for 3D model retrieval. The geometric saliency map is computed based on the
vertex curvature. The test facial triangle is then generated based on the
saliency map, which is applied to compare with the standard facial triangle.
The face and non-face models are then discriminated. The experiments and
comparisons prove the effectiveness of the proposed framework
Distributed Rate and Power Control in Vehicular Networks
The focus of this paper is on the rate and power control algorithms in
Dedicated Short Range Communication (DSRC) for vehicular networks. We first
propose a utility maximization framework by leveraging the well-developed
network congestion control, and formulate two subproblems, one on rate control
with fixed transmit powers and the other on power control with fixed rates.
Distributed rate control and power control algorithms are developed to solve
these two subproblems, respectively, and are proved to be asymptotically
optimal. Joint rate and power control can be done by using the two algorithms
in an alternating fashion. The performance enhancement of our algorithms
compared with a recent rate control algorithm, called EMBARC, is evaluated by
using the network simulator ns2.Comment: Submitted to IEEE/ACM Transactions on Networkin
Topological metal bands with double-triple-point fermions in optical lattices
Novel fermionic quasiparticles with integer pseudospins in some energy bands,
such as pseudospin-1 triple-point fermions, recently attract increasing
interest since they are beyond the conventional spin- Dirac and Weyl
counterparts. In this paper, we propose a class of pseudospin-1 fermioic
excitations emerging in topological metal bands, dubbed double-triple-point
(DTP) fermions. We first present a general three-band continuum model with
symmetry in three dimensions, which has three types of threefold
degenerate points in the bands classified by their topological charges
, respectively. They are dubbed DTPs as spin-1 generalization of
double-Weyl points. We then construct two-dimensional and three-dimensional
tight-binding lattice models of topological metal bands with exotic DTP
fermions near the DTPs. In two dimensions, the band gaps close at a trivial DTP
with zero Berry phase, which occurs at the transition between the normal and
topological insulator phases. In three dimensions, the topological properties
of three different DTP fermions in lattice systems are further investigated,
and the effects of breaking symmetry are also studied, which generally
leads to splitting each quadratic DTP into two linear triple points and gives
topological phase diagrams. Using ultracold fermionic atoms in optical
lattices, the proposed models can be realized and the topological properties of
the DTP fermions can be detected.Comment: 11 pages, 9 figures; accepted in PR
Exploring topological double-Weyl semimetals with cold atoms in optical lattices
We explore the topological properties of double-Weyl semimetals with cold
atoms in optical lattices. We first propose to realize a tight-binding model of
simulating the double-Weyl semimetal with a pair of double-Weyl points by
engineering the atomic hopping in a three-dimensional optical lattice. We show
that the double-Weyl points with topological charges of \ behave as sink
and source of Berry flux in momentum space connecting by two Fermi arcs and
they are stabilized by the \ point-group symmetry. By applying a
realizable \ breaking term, we find that each double-Weyl point splits
into two single-Weyl points and obtain rich phase diagrams in the parameter
space spanned by the strengths of an effective Zeeman term and the \
breaking term, which contains a topological and a normal insulating phases and
two topological Weyl semimetal phases with eight and four single-Weyl points,
apart from the double-Weyl semimetal phase. Furthermore, we demonstrate with
numerical simulations that (i) the mimicked double- and single-Weyl points can
be detected by measuring the atomic transfer fractions after a Bloch
oscillation; (ii) the Chern number of different quantum phases in the phase
diagram can be extracted from the center shift of the hybrid Wannier functions,
which can be directly measured with the time-of-flight imaging; (iii) the band
topology of the \ symmetric Bloch Hamiltonian can be detected simply from
measuring the spin polarization at the high symmetry momentum points with a
condensate in the optical lattice. The proposed system would provide a
promising platform for elaborating the intrinsic exotic physics of double-Weyl
semimetals and the related topological phase transitions.Comment: 12 pages, 7 figures; accepted by PR
Long-term photometric behaviour of the eclipsing Z Cam-type dwarf nova AY Psc
New eclipse timings of the Z Cam-type dwarf nova AY Psc were measured and the
orbital ephemeris was revised. Based on the long-term AAVSO data, moreover, the
outburst behaviors were also explored. Our analysis suggests that the normal
outbursts are quasi-periodic, with an amplitude of mag and a
period of days. The amplitude vs. recurrence-time relation
of AY Psc is discussed, and we concluded that this relation may represents
general properties of dwarf nova (DN) outbursts. The observed standstill ends
with an outburst, which is inconsistent with the general picture of Z Cam-type
stars. This unusual behavior was considered to be related to the mass-transfer
outbursts. Moreover, the average luminosity is brighter during standstills than
during outburst cycles. The changes in brightness marks the variations in
due to the disc of AY Psc is nearly steady state.
value was limited to the range from to
. More detailed examination shows that there
are a few small outbursts presence during standstills. These events with
amplitudes of mag are very similar to the stunted outbursts
reported in some NLs. We discussed several possible mechanisms and suggested
that the most reasonable mechanism for these stunted outbursts is a changing
mass-transfer rate.Comment: 12 pages, 10 figure
Double cyclic variations in orbital period of the eclipsing cataclysmic variable EX Dra
EX Dra is a long-period eclipsing dwarf nova with mag amplitude
outbursts. This star has been monitored photometrically from November, 2009 to
March, 2016 and 29 new mid-eclipse times were obtained. By using new data
together with the published data, the best fit to the curve indicate that
the orbital period of EX Dra have an upward parabolic change while undergoing
double-cyclic variations with the periods of 21.4 and 3.99 years, respectively.
The upward parabolic change reveals a long-term increase at a rate of
. The evolutionary theory of
cataclysmic variables (CVs) predicts that, as a CV evolves, the orbital period
should be decreasing rather than increasing. Secular increase can be explained
as the mass transfer between the secondary and primary or may be just an
observed part of a longer cyclic change. Most plausible explanation for the
double-cyclic variations is a pair of light travel-time effect via the presence
of two companions. Their masses are determined to be
and . When the two companions are coplanar to the orbital plane of the
central eclipsing pair, their masses would match to brown dwarfs.Comment: 8 pages, 5 figure
Binocular parallax stereo imaging based on correlation matching algorithm
The intensity fluctuation correlation of pseudo-thermal light can be utilized
to realize binocular parallax stereo imaging (BPSI). With the help of
correlation matching algorithm, the matching precision of feature points can
reach one pixel authentically. The implementations of the proposed BPSI system
with real objects were demonstrated in detail. And the experimental results
indicated that the proposed system performs better when the object's
superficial characteristics are not obvious, for example its surface
reflectivity is constant
Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg
New Multi-color photometric observation are presented for
W UMa type eclipsing binary V1073 Cyg. The multi-color light curves analysis
with the Wilson-Devinney(W-D) procedure acquired the absolute parameters of
this system, showing that V1073Cyg is a shallow contact binary system with
fill-out factor . We collected all available times of light
minima spanning 119 years including CCD data to construct the O-C curve and
made detailed O-C analysis. The O-C diagram shows that the period change is
complex. There exist a long-term continuous decrease and a cyclic variation.
The period is decreasing at a rate of
, and with the period decrease, V1073 Cyg will evolve to
deep contact stage. The cyclic variation with a period of and an amplitude of may be explained by the
magnetic activity of one or both components or the light travel time effect
(LTTE) caused by a distant third companion with
.Comment: 15 pages, 5 figure
First photometric study of ultrashort-period contact binary 1SWASP J140533.33+114639.1
In this paper, CCD photometric light curves for the short-period eclipsing
binary 1SWASP J140533.33+114639.1 (hereafter J1405) in the bands are
presented and analyzed using the 2013 version of the Wilson-Devinney (W-D)
code. It is discovered that the J1405 is a W-subtype shallow contact binary
with a contact degree of = 7.9 0.5\% and a mass ratio of = 1.55
0.02. In order to explain the asymmetric light curves of the system, a
cool star-spot on the more massive component was employed. This shallow contact
eclipsing binary may be formed from a short-period detached system through the
orbital shrinkage due to angular momentum loss. Based on method, the
variation of the orbital period was studied using all the available times of
the minimum light. The diagram reveals that the period is increasing
continuously at a rate of days yr, which can
be explained by mass transfer from the less massive component to the more
massive one
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