8,568 research outputs found
Kinetic study for hopping conduction through DNA molecules
Recent experiments indicated that disorder effect in DNA may lead to a
transition of the charge transport mechanism from band resonant tunnelling to
thermal activated hopping. In this letter, based on Mott's variable-range
hopping theory we present a kinetic study for the charge transport properties
of DNA molecules. Beyond the conventional argument in large-scale systems, our
numerical study for finite-size DNA molecules reveals a number of unique
features for (i) the I-V characteristics, (ii) the temperature and length
dependence, and (iii) the transition from conducting to insulating behaviors.Comment: 3 pages, 3 figures, submitted to Appl. Phys. Let
Precision measurement of charge number with optomechanically induced transparency
We propose a potentially practical scheme to precisely measure the charge
numbers of small charged objects by optomechanical systems using
optomechanically induced transparency (OMIT). In contrast to the conventional
measurements based on the noise backaction on the optomechanical systems, our
scheme makes use of the small deformation of the mechanical resonator sensitive
to the charge number of the nearby charged object, which could achieve the
detection of a single charge. The relationship between the charge number and
the window width of the OMIT is investigated and the feasibility of the scheme
is justified by numerical simulation using currently available experimental
values.Comment: 6 pages,4 figure
Cavity QED treatment of scattering-induced efficient free-space excitation and collection in high-Q whispering-gallery microcavities
Whispering-gallery microcavity laser possesses ultralow threshold, whereas
convenient free-space optical excitation and collection suffer from low
efficiencies due to its rotational symmetry. Here we analytically study a
three-dimensional microsphere coupled to a nano-sized scatterer in the
framework of quantum optics. It is found that the scatterer is capable of
coupling light in and out of the whispering-gallery modes (WGMs) without
seriously degrading their high-Q properties, while the microsphere itself plays
the role of a lens to focus the input beam on the scatterer and vice versa. Our
analytical results show that (1) the high-Q WGMs can be excited in free space,
and (2) over 50% of the microcavity laser emission can be collected within less
than . This coupling system holds great potential for low
threshold microlasers free of external couplers.Comment: 10 pages, 8 figure
Strongly enhanced light-matter interaction in a hybrid photonic-plasmonic resonator
We propose a hybrid photonic-plasmonic resonant structure which consists of a
metal nanoparticle (MNP) and a whispering gallery mode (WGM) microcavity. It is
found that the hybrid mode enables a strong interaction between the light and
matter, and the single-atom cooperativity is enhanced by more than two orders
of magnitude compared to that in a bare WGM microcavity. This remarkable
improvement originates from two aspects: (1) the MNP offers a highly enhanced
local field in the vicinity of an emitter, and (2), surprisingly, the
high-\textit{Q} property of WGMs can be maintained in the presence of the MNP.
Thus the present system has great advantages over a single microcavity or a
single MNP, and holds great potential in quantum optics, nonlinear optics and
highly sensitive biosening.Comment: 5 pages, 4 figure
Quantum Error Correcting Codes Using Qudit Graph States
Graph states are generalized from qubits to collections of qudits of
arbitrary dimension , and simple graphical methods are used to construct
both additive and nonadditive quantum error correcting codes. Codes of distance
2 saturating the quantum Singleton bound for arbitrarily large and are
constructed using simple graphs, except when is odd and is even.
Computer searches have produced a number of codes with distances 3 and 4, some
previously known and some new. The concept of a stabilizer is extended to
general , and shown to provide a dual representation of an additive graph
code.Comment: Version 4 is almost exactly the same as the published version in
Phys. Rev.
Overall Evolution of Realistic Gamma-ray Burst Remnant and Its Afterglow
Conventional dynamic model of gamma-ray burst remnants is found to be
incorrect for adiabatic blastwaves during the non-relativistic phase. A new
model is derived, which is shown to be correct for both radiative and adiabatic
blastwaves during both ultra-relativistic and non-relativistic phase. Our model
also takes the evolution of the radiative efficiency into account. The
importance of the transition from the ultra-relativistic phase to the
non-relativistic phase is stressed.Comment: 9 pages, aasms4 style, 3 ps figures, minor changes, will be published
in Chin. Phys. Let
Thermodynamic of the Ghost Dark Energy Universe
Recently, the vacuum energy of the QCD ghost in a time-dependent background
is proposed as a kind of dark energy candidate to explain the acceleration of
the Universe. In this model, the energy density of the dark energy is
proportional to the Hubble parameter , which is the Hawking temperature on
the Hubble horizon of the Friedmann-Robertson-Walker (FRW) Universe. In this
paper, we generalized this model and choice the Hawking temperature on the
so-called trapping horizon, which will coincides with the Hubble temperature in
the context of flat FRW Universe dominated by the dark energy component. We
study the thermodynamics of Universe with this kind of dark energy and find
that the entropy-area relation is modified, namely, there is an another new
term besides the area term.Comment: 8 pages, no figure
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