14,234 research outputs found
Optical generation of hybrid entangled state via entangling single-photon-added coherent state
We propose a feasible scheme to realize the optical entanglement of
single-photon-added coherent state (SPACS) and show that, besides the Sanders
entangled coherent state, the entangled SPACS also leads to new forms of hybrid
entanglement of quantum Fock state and classical coherent state. We probe the
essential difference of two types of hybrid entangled state (HES). This HES
provides a novel link between the discrete- and the continuous-variable
entanglement in a natural way.Comment: 6 pages, 2 figure
Optical characterization of BiSe in a magnetic field: infrared evidence for magnetoelectric coupling in a topological insulator material
We present an infrared magneto-optical study of the highly thermoelectric
narrow-gap semiconductor BiSe. Far-infrared and mid-infrared (IR)
reflectance and transmission measurements have been performed in magnetic
fields oriented both parallel and perpendicular to the trigonal axis of
this layered material, and supplemented with UV-visible ellipsometry to obtain
the optical conductivity . With lowering of temperature we
observe narrowing of the Drude conductivity due to reduced quasiparticle
scattering, as well as the increase in the absorption edge due to direct
electronic transitions. Magnetic fields dramatically
renormalize and asymmetrically broaden the strongest far-IR optical phonon,
indicating interaction of the phonon with the continuum free-carrier spectrum
and significant magnetoelectric coupling. For the perpendicular field
orientation, electronic absorption is enhanced, and the plasma edge is slightly
shifted to higher energies. In both cases the direct transition energy is
softened in magnetic field.Comment: Final versio
Control of hierarchical polymer mechanics with bioinspired metal-coordination dynamics.
In conventional polymer materials, mechanical performance is traditionally engineered via material structure, using motifs such as polymer molecular weight, polymer branching, or block copolymer design. Here, by means of a model system of 4-arm poly(ethylene glycol) hydrogels crosslinked with multiple, kinetically distinct dynamic metal-ligand coordinate complexes, we show that polymer materials with decoupled spatial structure and mechanical performance can be designed. By tuning the relative concentration of two types of metal-ligand crosslinks, we demonstrate control over the material's mechanical hierarchy of energy-dissipating modes under dynamic mechanical loading, and therefore the ability to engineer a priori the viscoelastic properties of these materials by controlling the types of crosslinks rather than by modifying the polymer itself. This strategy to decouple material mechanics from structure is general and may inform the design of soft materials for use in complex mechanical environments. Three examples that demonstrate this are provided
Full one-loop electroweak corrections to associated productions at linear colliders
We study the complete one-loop electroweak(EW) corrections to the processes
of single charged Higgs boson production associated with a neutral Higgs
boson and a gauge boson in the framework of the minimal
supersymmetric standard model(MSSM). Numerical results at the
benchmark point as proposed in the SPA project, are presented for
demonstration. We find that for the process the EW
relative correction can be either positive or negative and in the range of
in our chosen parameter space. While for the processes
the corrections generally reduce the Born cross
sections and the EW relative corrections are typically of order .Comment: 22 pages, 20 figures, LaTex, to be appeared in PR
Influence of intrinsic decoherence on nonclassical properties of the output of a Bose-Einstein condensate
We investigate nonclassical properties of the output of a Bose-Einstein
condensate in Milburn's model of intrinsic decoherence. It is shown that the
squeezing property of the atom laser is suppressed due to decoherence.
Nevertheless, if some very special conditions were satisfied, the squeezing
properties of atom laser could be robust against the decoherence.Comment: 17 pages, 5 figures, Late
Achieving sustainable irrigation water withdrawals: global impacts on food security and land use
Unsustainable water use challenges the capacity of water resources to ensure food security and continued growth of the economy. Adaptation policies targeting future water security can easily overlook its interaction with other sustainability metrics and unanticipated local responses to the larger-scale policy interventions. Using a global partial equilibrium grid-resolving model SIMPLE-G, and coupling it with the global Water Balance Model, we simulate the consequences of reducing unsustainable irrigation for food security, land use change, and terrestrial carbon. A variety of future (2050) scenarios are considered that interact irrigation productivity with two policy interventions— inter-basin water transfers and international commodity market integration. We find that pursuing sustainable irrigation may erode other development and environmental goals due to higher food prices and cropland expansion. This results in over 800 000 more undernourished people and 0.87 GtC additional emissions. Faster total factor productivity growth in irrigated sectors will encourage more aggressive irrigation water use in the basins where irrigation vulnerability is expected to be reduced by inter-basin water transfer. By allowing for a systematic comparison of these alternative adaptations to future irrigation vulnerability, the global gridded modeling approach offers unique insights into the multiscale nature of the water scarcity challenge
Circular Optical Nanoantennas: An Analytical Theory
An entirely analytical theory is provided for describing the resonance
properties of optical nanoantennas made of a stack of homogeneous discs, i.e.
circular patch nanoantennas. It consists in analytically calculating the phase
accumulation of surface plasmon polaritons across the resonator and an
additional contribution from the complex reflection coefficient at the antenna
termination. This makes the theory self-contained with no need for fitting
parameters. The very antenna resonances are then explained by a simple
Fabry-Perot resonator model. Predictions are compared to rigorous simulations
and show excellent agreement. Using this analytical model, circular antennas
can be tuned by varying the composition of the stack
Associated Production of a Top Quark and a Charged Higgs Boson
We compute the inclusive and differential cross sections for the associated
production of a top quark along with a charged Higgs boson at hadron colliders
to next-to-leading order (NLO) in perturbative quantum chromodynamics (QCD) and
in supersymmetric QCD. For small Higgs boson masses we include top quark pair
production diagrams with subsequent top quark decay into a bottom quark and a
charged Higgs boson. We compare the NLO differential cross sections obtained in
the bottom parton picture with those for the gluon-initiated production process
and find good agreement. The effects of supersymmetric loop contributions are
explored. Only the corrections to the Yukawa coupling are sizable in the
potential discovery region at the CERN Large Hadron Collider (LHC). All
expressions and numerical results are fully differential, permitting selections
on the momenta of both the top quark and the charged Higgs boson.Comment: 15 pages, 9 figures; section, figures, equations and references
added, version to appear in PRD, 33 pages, 11 figure
Kinematics of the swimming of Spiroplasma
\emph{Spiroplasma} swimming is studied with a simple model based on
resistive-force theory. Specifically, we consider a bacterium shaped in the
form of a helix that propagates traveling-wave distortions which flip the
handedness of the helical cell body. We treat cell length, pitch angle, kink
velocity, and distance between kinks as parameters and calculate the swimming
velocity that arises due to the distortions. We find that, for a fixed pitch
angle, scaling collapses the swimming velocity (and the swimming efficiency) to
a universal curve that depends only on the ratio of the distance between kinks
to the cell length. Simultaneously optimizing the swimming efficiency with
respect to inter-kink length and pitch angle, we find that the optimal pitch
angle is 35.5 and the optimal inter-kink length ratio is 0.338, values
in good agreement with experimental observations.Comment: 4 pages, 5 figure
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