6,716 research outputs found
More hidden heavy quarkonium molecules and their discovery decay modes
To validate the molecular description of the observed
and , it is valuable to investigate their counterparts,
denoted as in this work, and the corresponding decay modes.
In this work, we present an analysis of the using flavor
symmetry. We also use the effective Lagrangian based on the heavy quark
symmetry to explore the rescattering mechanism and calculate the partial widths
for the isospin conserved channels . The
predicted partial widths are of an order of MeV for ,
which correspond to branching ratios of the order of . For
, the partial widths are a few hundreds of keV and
the branching ratios are about . Future experimental measurements can
test our predictions on the partial widths and thus examine the molecule
description of heavy quarkoniumlike exotic states.Comment: 11 pages, 2 figures; accepted by Phys. Rev.
Frames and operators in Schatten classes
Let be a compact operator on a separable Hilbert space . We show that,
for , belongs to the Schatten class if and only if
for \emph{every} frame in ; and for
, belongs to if and only if for
\emph{some} frame in . Similar conditions are also obtained in
terms of the sequence and the double-indexed sequence
.Comment: 27 page
Optomechanical Devices and Sensors Based on Plasmonic Metamaterial Absorbers
Surface plasmon resonance is the resonant oscillations of the free electrons at the interface between two media with different signs in real permittivities, e.g. a metal and a dielectric, stimulated by light. Plasmonics is a promising field of study, because electron oscillations inside a subwavelength space at optical frequencies simultaneously overcome the limit of diffraction in conventional photonics and carrier mobilities in semiconductor electronics. Due to the subwavelength confinement, plasmonic resonances can strongly enhance local fields and, hence, magnify light-matter interactions. Optical absorbers based on plasmonic metamaterials can absorb light resonantly at the operating wavelengths with up to 100% efficiency. We have explored plasmonic absorbers at infrared wavelengths for thermal detectors, e.g. a gold nanostrip antenna absorber that can absorb 10-times light using only 2% of material consumption comparing to a uniform gold film.
In an optomechanical device, the optical mode and mechanical mode are mutually influenced, through the optical forces exerted on the mechanical oscillator and the detuning of optical resonance by the mechanical oscillator, so that the mechanical oscillations are either amplified or suppressed by light. We designed an optomechanical device integrated with plasmonic metamaterial absorber on a membrane mechanical oscillator, wherein a tunable Fano-resonant absorption in the absorber arises from the coupling between the plasmonic and Fabry-Perot reonsances. The absorber traps the incident light and heat up the membrane, causing an increase in thermal stress and a normal plasmomechanical force on it. This is a light-absorption-dependent elastic force arising from the opto-thermo-mechanical interactions. Due to the finite thermal response time in the membrane, the elastic plasmomechanical force is delayed and, consequently, generates a viscous component modifying the damping rate of the mechanical oscillator. We have observed optomechanical amplification and cooling in the device at designed detuning conditions. In particular, on the condition that the optomechanical gain beats the intrinsic mechanical damping, the oscillation becomes coherent, i.e. phonon lasing. We successfully demonstrated phonon lasing with a threshold power of 19 ΞΌW. This device is promising as an integration-ready coherent phonon source and may set the stage for applications in fundamental studies and ultrasonic imaging modalities
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