6,429 research outputs found
Coupled-channel analysis of the possible , and molecular states
We perform a coupled-channel study of the possible deuteron-like molecules
with two heavy flavor quarks, including the systems of with
double charm, with double bottom and
with both charm and bottom, within the
one-boson-exchange model. In our study, we take into account the S-D mixing
which plays an important role in the formation of the loosely bound deuteron,
and particularly, the coupled-channel effect in the flavor space. According to
our calculation, the states and
with double charm, the states
,
and
with double bottom, and
the states and
with both charm and bottom are good
molecule candidates. However, the existence of the states
with double charm and
with both charm and bottom is ruled out.Comment: 1 figure added, published in Physical Review
CW-pumped telecom band polarization entangled photon pair generation in a Sagnac interferometer
A polarization entangled photon pair source is widely used in many quantum
information processing applications such as teleportation, quantum swapping,
quantum computation and high precision quantum metrology. Here, we report on
the generation of a continuous-wave pumped degenerated 1550 nm polarization
entangled photon pair source at telecom wavelength using a type-II
phase-matched periodically poled KTiOPO4 crystal in a Sagnac interferometer.
Hong-Ou-Mandel-type interference measurement shows the photon bandwidth of 2.4
nm. High quality of entanglement is verified by various kinds of measurements,
for example two-photon interference fringes, Bell inequality and quantum states
tomography. The wavelength of photons can be tuned over a broad range by
changing the temperature of crystal or pump power without losing the quality of
entanglement. This source will be useful for building up long-distance quantum
networks
BKP hierarchy and Pfaffian point process
Inspired by Okounkov's work [\emph{Selecta Mathematica}, 7(1):57--81, 2001]
which relates KP hierarchy to determinant point process, we establish a
relationship between BKP hierarchy and Pfaffian point process. We prove that
the correlation function of the shifted Schur measures on strict partitions can
be expressed as a Pfaffian of skew symmetric matrix kernel, whose elememts are
certain vacuum expectations of neutral fermions. We further show that the
matrix integrals solution of BKP hierarchy can also induce a certain Pfaffian
point process.Comment: 17 page
Enhanced spectral sensitivity of a chip-scale photonic-crystal slow-light interferometer
We experimentally demonstrate that the spectral sensitivity of a Mach-Zehnder
(MZ) interferometer can be enhanced through structural slow light. We observe a
20 times enhancement by placing a dispersion-engineered-slow-light
photonic-crystal waveguide in one arm of a fibre-based MZ interferometer. The
spectral sensitivity of the interferometer increases roughly linearly with the
group index, and we have quantified the resolution in terms of the spectral
density of interference fringes. These results show promise for the use of
slow-light methods for developing novel tools for optical metrology and,
specifically, for compact high-resolution spectrometers
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