4,659 research outputs found
Reading inflation expectations from CPI futures
Consumer price indexes ; Inflation (Finance)
Oil price volatility and U.S. macroeconomic activity
Oil shocks exert influence on macroeconomic activity through various channels, many of which imply a symmetric effect. However, the effect can also be asymmetric. In particular, sharp oil price changes-either increases or decreases-may reduce aggregate output temporarily because they delay business investment by raising uncertainty or induce costly sectoral resource reallocation. Consistent with these asymmetric-effect hypotheses, the authors find that a volatility measure constructed using daily crude oil futures prices has a negative and significant effect on future gross domestic product (GDP) growth over the period 1984-2004. Moreover, the effect becomes more significant after oil price changes are also included in the regression to control for the symmetric effect. The evidence here provides economic rationales for Hamilton's (2003) nonlinear oil shock measure: It captures overall effects, both symmetric and asymmetric, of oil price shocks on output.Petroleum products - Prices ; Macroeconomics
Is the meson dynamically generated?
We study the problem whether the meson is generated `dynamically'. A
pedagogical analysis on the toy O(N) linear sigma model is performed and we
find that the large limit and the limit does not
commute. The sigma meson may not necessarily be described as a dynamically
generated resonance. On the contrary, the sigma meson may be more appropriately
described by considering it as an explicit degree of freedom in the effective
lagrangian.Comment: Contribution to ``Quark Confinement and Hadron Spectrum VII'', 2--7
Sept. 2006, Ponta Delgada, Acores, Portuga
Spin interference and Fano effect in electron transport through a mesoscopic ring side-coupled with a quantum dot
We investigate the electron transport through a mesoscopic ring side-coupled
with a quantum dot(QD) in the presence of Rashba spin-orbit(SO) interaction. It
is shown that both the Fano resonance and the spin interference effects play
important roles in the electron transport properties. As the QD level is around
the Fermi energy, the total conductance shows typical Fano resonance line
shape. By applying an electrical gate voltage to the QD, the total transmission
through the system can be strongly modulated. By threading the mesoscopic ring
with a magnetic flux, the time-reversal symmetry of the system is broken, and a
spin polarized current can be obtained even though the incident current is
unpolarized.Comment: 5 pages, 5 figure
Confinement induced resonances in anharmonic waveguides
We develop the theory of anharmonic confinement-induced resonances (ACIR).
These are caused by anharmonic excitation of the transverse motion of the
center of mass (COM) of two bound atoms in a waveguide. As the transverse
confinement becomes anisotropic, we find that the COM resonant solutions split
for a quasi-1D system, in agreement with recent experiments. This is not found
in harmonic confinement theories. A new resonance appears for repulsive
couplings () for a quasi-2D system, which is also not seen with
harmonic confinement. After inclusion of anharmonic energy corrections within
perturbation theory, we find that these ACIR resonances agree extremely well
with anomalous 1D and 2D confinement induced resonance positions observed in
recent experiments. Multiple even and odd order transverse ACIR resonances are
identified in experimental data, including up to N=4 transverse COM quantum
numbers.Comment: 16 pages,6 fugure
Is the meson a dynamically generated resonance? -- a lesson learned from the O(N) model and beyond
O(N) linear model is solvable in the large limit and hence
provides a useful theoretical laboratory to test various unitarization
approximations. We find that the large limit and the
limit do not commute. In order to get the correct large spectrum one has
to firstly take the large limit. We argue that the meson may
not be described as generated dynamically. On the contrary, it is most
appropriately described at the same level as the pions, i.e, both appear
explicitly in the effective lagrangian. Actually it is very likely the
meson responsible for the spontaneous chiral symmetry breaking in a lagrangian
with linearly realized chiral symmetry.Comment: 15 pages, 3 figurs; references added; discussions slightly modified;
revised version accepted by IJMP
Spontaneously generated atomic entanglement in free space: reinforced by incoherent pumping
We study spontaneously generated entanglement (SGE) between two identical
multilevel atoms in free space via vacuum-induced radiative coupling. We show
that the SGE in two-atom systems may initially increase with time but
eventually vanishes in the time scale determined by the excited state lifetime
and radiative coupling strength between the two atoms. We demonstrate that a
steady-state SGE can be established by incoherently pumping the excited states
of the two-atom system. We have shown that an appropriate rate of incoherent
pump can help producing optimal SGE. The multilevel systems offer us more
chanel to establish entanglement. The system under consideration could be
realized in a tight trap or atoms/ions doped in a solid substrate.Comment: have some difference with published version (please see PRA
RNA-Based Compositions and Adjuvants for Prophylactic and Therapeutic Treatment
The present invention is directed towards an artificial RNA nano structure comprising multiple external strands of RNA, each external strand comprising about 40-50 nucleotides; one internal strand of RNA comprising more than about 50 nucleotides; the internal strands and external strands assembled to form a triangle nanostructure, a square nanostructure, or a polygon nanostructure and a pRNA three-way junction (3WJ) motif at each vertex of the nanostructure. Such nanostructure can be provided in a composition together with an adjuvant for use in inducing the production of high affinity neutralizing antibodies or inhibitory antibodies, inducing the production of cytokines, inducing an immune response in a subject, or a combination thereof
Acoustic black holes from supercurrent tunneling
We present a version of acoustic black holes by using the principle of the
Josephson effect. We find that in the case two superconductors and are
separated by an insulating barrier, an acoustic black hole may be created in
the middle region between the two superconductors. We discuss in detail how to
describe an acoustic black hole in the Josephson junction and write the metric
in the langauge of the superconducting electronics. Our final results infer
that for big enough tunneling current and thickness of the junction,
experimental verification of the Hawking temperature could be possible.Comment: 15pages,1 figure, to appear in IJMP
Investigation of PrintingâBased Graded BulkâHeterojunction Organic Solar Cells
A 2âstep method involving the evaporation of solvent through surface encapsulation and induced alignment (ESSENCIAL) has been used to create a compositionally graded active layer of interspersed acceptor and donor domains by printingâbased technologies, which can be used to fabricate solar cells with higher performance than that from traditional bulk heterojunction fabrication methods. Herein, to clarify the fundamental mechanism of the performance improvement, a multiâscale simulation has been conducted to compare solar cells resulting from these two types of processing. The multiâscale simulation identified the underlying improvements of the ESSENCIAL morphology over traditional morphologies. Monte Carlo simulations obtained higher holeâmobility values and lower monomolecular recombination rates for the ESSENCIALâfabricated cells that, in conjunction with the optical and electrical components, showed higher shortâcircuit currents, fill factors, and efficiencies, as indicated experimentally. The simulation offers the unique ability to model the varied active layer compositions and elucidate the underlying solar cell physics of complex morphologies.Explaining the physics: A multiâscale simulation composed of optical, Monte Carlo, and electrical simulations is used to identify and understand the improvements of a new, printingâbased morphology for organic solar cells. Organic solar cells with normal bulkâheterojunction morphologies and the new printingâbased morphologies are simulated and compared to identify the latter's fundamental improvements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111163/1/414_ftp.pd
- âŠ