906 research outputs found
Planetary Systems in Binaries. I. Dynamical Classification
Many recent observational studies have concluded that planetary systems
commonly exist in multiple-star systems. At least ~20% of the known extrasolar
planetary systems are associated with one or more stellar companions. The
orbits of stellar binaries hosting planetary systems are typically wider than
100 AU and often highly inclined with respect to the planetary orbits. The
effect of secular perturbations from such an inclined binary orbit on a coupled
system of planets, however, is little understood theoretically. In this paper
we investigate various dynamical classes of double-planet systems in binaries
through numerical integrations and we provide an analytic framework based on
secular perturbation theories. Differential nodal precession of the planets is
the key property that separates two distinct dynamical classes of multiple
planets in binaries: (1) dynamically-rigid systems in which the orbital planes
of planets precess in concert as if they were embedded in a rigid disk, and (2)
weakly-coupled systems in which the mutual inclination angle between initially
coplanar planets grows to large values on secular timescales. In the latter
case, the quadrupole perturbation from the outer planet induces additional
Kozai cycles and causes the orbital eccentricity of the inner planet to
oscillate with large amplitudes. The cyclic angular momentum transfer from a
stellar companion propagating inward through planets can significantly alter
the orbital properties of the inner planet on shorter timescales. This
perturbation propagation mechanism may offer important constraints on the
presence of additional planets in known single-planet systems in binaries.Comment: 14 pages, 14 figures, to appear in Ap
Quantum diffraction and interference of spatially correlated photon pairs and its Fourier-optical analysis
We present one- and two-photon diffraction and interference experiments
involving parametric down-converted photon pairs. By controlling the divergence
of the pump beam in parametric down-conversion, the diffraction-interference
pattern produced by an object changes from a quantum (perfectly correlated)
case to a classical (uncorrelated) one. The observed diffraction and
interference patterns are accurately reproduced by Fourier-optical analysis
taking into account the quantum spatial correlation. We show that the relation
between the spatial correlation and the object size plays a crucial role in the
formation of both one- and two-photon diffraction-interference patterns.Comment: 10 pages, 13 figures, rev.
Relaxing a constraint on the number of messengers in a low-scale gauge mediation
We propose a mechanism for relaxing a constraint on the number of messengers
in low-scale gauge mediation models. The Landau pole problem for the
standard-model gauge coupling constants in the low-scale gauge mediation can be
circumvented by using our mechanism. An essential ingredient is a large
positive anomalous dimension of messenger fields given by a large Yukawa
coupling in a conformal field theory at high energies. The positive anomalous
dimension reduces the contribution of the messengers to the beta function of
the standard-model gauge couplings.Comment: 22pages; v2:explanations expanded in sec.3.2, reference adde
Four-Photon Quantum Interferometry at a Telecom Wavelength
We report the experimental demonstration of four-photon quantum interference
using telecom-wavelength photons. Realization of multi-photon quantum
interference is essential to linear optics quantum information processing and
measurement-based quantum computing. We have developed a source that
efficiently emits photon pairs in a pure spectrotemporal mode at a telecom
wavelength region, and have demonstrated the quantum interference exhibiting
the reduced fringe intervals that correspond to the reduced de Broglie
wavelength of up to the four photon `NOON' state. Our result should open a path
to practical quantum information processing using telecom-wavelength photons.Comment: 4 pages, 4 figure
Phase Separation of Multi-Component Bose-Einstein Condensates of Trapped Atoms and Molecules with a Homonuclear Feshbach Resonance
We investigate phase separation of Bose-Einstein condensates (BECs) of
two-component atoms and one-component molecules with a homonuclear Feshbach
resonance. We develop a full model for dilute atomic and molecular gases
including correlation of the Feshbach resonance and all kinds of interparticle
interactions, and numerically calculate order parameters of the BECs in
spherical harmonic oscillator traps at zero temperature with the Bogoliubov's
classical field approximation. As a result, we find out that the Feshbach
resonance can induce two types of phase separation. The actual phase structures
and density profiles of the trapped gases are predicted in the whole parameter
region, from the atom dominant regime to the molecule dominant regime. We focus
on the role of the molecules in the phase separation. Especially in the atom
dominant regime, the role of the molecules is described through effective
interactions derived from our model. Furthermore we show that a perturbative
and semi-classical limit of our model reproduces the conventional atomic BEC
(single-channel) model.Comment: 11pages, 4 figure
Physical conditions of the interstellar medium in star-forming galaxies at z~1.5
We present results from Subaru/FMOS near-infrared (NIR) spectroscopy of 118
star-forming galaxies at in the Subaru Deep Field. These galaxies
are selected as [OII]3727 emitters at 1.47 and 1.62 from
narrow-band imaging. We detect H emission line in 115 galaxies,
[OIII]5007 emission line in 45 galaxies, and H,
[NII]6584, and [SII]6716,6731 in 13, 16, and 6
galaxies, respectively. Including the [OII] emission line, we use the six
strong nebular emission lines in the individual and composite rest-frame
optical spectra to investigate physical conditions of the interstellar medium
in star-forming galaxies at 1.5. We find a tight correlation between
H and [OII], which suggests that [OII] can be a good star formation
rate (SFR) indicator for galaxies at . The line ratios of
H/[OII] are consistent with those of local galaxies. We also find that
[OII] emitters have strong [OIII] emission lines. The [OIII]/[OII] ratios are
larger than normal star-forming galaxies in the local Universe, suggesting a
higher ionization parameter. Less massive galaxies have larger [OIII]/[OII]
ratios. With evidence that the electron density is consistent with local
galaxies, the high ionization of galaxies at high redshifts may be attributed
to a harder radiation field by a young stellar population and/or an increase in
the number of ionizing photons from each massive star.Comment: Fixed a minor issue with LaTeX table numberin
Scaling analysis of Kondo screening cloud in a mesoscopic ring with an embedded quantum dot
The Kondo effect is theoretically studied in a quantum dot embedded in a
mesoscopic ring. The ring is connected to two external leads, which enables the
transport measurement. Using the "poor man's" scaling method, we obtain
analytical expressions of the Kondo temperature T_K as a function of the
Aharonov-Bohm phase \phi by the magnetic flux penetrating the ring. In this
Kondo problem, there are two characteristic lengths. One is the screening
length of the charge fluctuation, L_c=\hbar v_F/ |\epsilon_0|, where v_F is the
Fermi velocity and \epsilon_0 is the energy level in the quantum dot. The other
is the screening length of spin fluctuation, i.e., size of Kondo screening
cloud, L_K=\hbar v_F/ T_K. We obtain different expressions of T_K(\phi) for (i)
L_c \ll L_K \ll L, (ii) L_c \ll L \ll L_K, and (iii) L \ll L_c \ll L_K, where L
is the size of the ring. T_K is markedly modulated by \phi in cases (ii) and
(iii), whereas it hardly depends on \phi in case (i). We also derive
logarithmic corrections to the conductance at temperature T\gg T_K and an
analytical expression of the conductance at T\ll T_K, on the basis of the
scaling analysis.Comment: 21pages, 10 figure
Explicit Form of the Evolution Operator of Tavis-Cummings Model : Three and Four Atoms Cases
In this letter the explicit form of evolution operator of the Tavis-Cummings
model with three and four atoms is given. This is an important progress in
quantum optics or mathematical physics.Comment: Latex file, 10 pages. We combined quant-ph/0404034(the three atoms
case) and quant-ph/0406184(the four atoms case) into an article. to appear in
International Journal of Geometric Methods in Modern Physic
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