172 research outputs found
An SFPâFCC method for pricing and hedging early-exercise options under LĂ©vy processes
This paper extends the singular FourierâPadĂ© (SFP) method proposed by Chan [Singular FourierâPadĂ© series expansion of European option prices. Quant. Finance, 2018, 18, 1149â1171] for pricing/hedging early-exercise optionsâBermudan, American and discrete-monitored barrier optionsâunder a LĂ©vy process. The current SFP method is incorporated with the FilonâClenshawâCurtis (FCC) rules invented by DomĂnguez et al. [Stability and error estimates for FilonâClenshawâCurtis rules for highly oscillatory integrals. IMA J. Numer. Anal., 2011, 31, 1253â1280], and we call the new method SFPâFCC. The main purpose of using the SFPâFCC method is to require a small number of terms to yield fast error convergence and to formulate option pricing and option Greek curves rather than individual prices/Greek values. We also numerically show that the SFPâFCC method can retain a global spectral convergence rate in option pricing and hedging when the risk-free probability density function is piecewise smooth. Moreover, the computational complexity of the method is O((Lâ1)(N+1)( Ă log Ă)) with N, a (small) number of complex Fourier series terms, Ă, a number of Chebyshev series terms and L, the number of early-exercise/monitoring dates. Finally, we compare the accuracy and computational time of our method with those of existing techniques in numerical experiments
Lepton Flavor Violation in the SUSY-GUT Models with Lopsided Mass Matrix
The tiny neutrino masses measured in the neutrino oscillation experiments can
be naturally explained by the supersymmetric see-saw mechanism. If the
supersymmetry breaking is mediated by gravity, the see-saw models may predict
observable lepton flavor violating effects. In this work, we investigate the
lepton flavor violating process in the kind of neutrino mass
models based on the idea of the ``lopsided'' form of the charged lepton mass
matrix. The constraints set by the muon anomalous magnetic moment are taken
into account. We find the present models generally predict a much larger
branching ratio of than the experimental limit. Conversely,
this process may give strong constraint on the lepton flavor structure.
Following this constraint we then find a new kind of the charged lepton mass
matrix. The feature of the structure is that both the elements between the 2-3
and 1-3 generations are ``lopsided''. This structure produces a very small 1-3
mixing and a large 1-2 mixing in the charged lepton sector, which naturally
leads to small and the LMA solution for the solar neutrino
problem.Comment: 24 pages, 8 figure
Double Inflation in Supergravity and the Large Scale Structure
The cosmological implication of a double inflation model with hybrid + new
inflations in supergravity is studied. The hybrid inflation drives an inflaton
for new inflation close to the origin through supergravity effects and new
inflation naturally occurs. If the total e-fold number of new inflation is
smaller than , both inflations produce cosmologically relevant density
fluctuations. Both cluster abundances and galaxy distributions provide strong
constraints on the parameters in the double inflation model assuming
standard cold dark matter scenario. The future satellite
experiments to measure the angular power spectrum of the cosmic microwave
background will make a precise determination of the model parameters possible.Comment: 19 pages (RevTeX file
Effective String Theory of Vortices and Regge Trajectories
Starting from a field theory containing classical vortex solutions, we obtain
an effective string theory of these vortices as a path integral over the two
transverse degrees of freedom of the string. We carry out a semiclassical
expansion of this effective theory, and use it to obtain corrections to Regge
trajectories due to string fluctuations.Comment: 27 pages, revtex, 3 figures, corrected an error with the cutoff in
appendix E (was previously D), added more discussion of Fig. 3, moved some
material in section 9 to a new appendi
Structural, electronic, and magneto-optical properties of YVO
Optical and magneto-optical properties of YVO single crystal were studied
in FIR, visible, and UV regions. Two structural phase transitions at 75 K and
200 K were observed and established to be of the first and second order,
respectively. The lattice has an orthorhombic symmetry both above 200 K
as well as below 75 K, and is found to be dimerized monoclinic in
between. We identify YVO as a Mott-Hubbard insulator with the optical gap
of 1.6 eV. The electronic excitations in the visible spectrum are determined by
three -bands at 1.8, 2.4, and 3.3 eV, followed by the charge-transfer
transitions at about 4 eV. The observed structure is in good agreement with
LSDA+ band structure calculations. By using ligand field considerations, we
assigned these bands to the transitions to the , , and states. The strong temperature dependence of these
bands is in agreement with the formation of orbital order. Despite the small
net magnetic moment of 0.01 per vanadium, the Kerr effect of the order
of was observed for all three -bands in the magnetically
ordered phase . A surprisingly strong enhancement of
the Kerr effect was found below 75 K, reaching a maximum of . The
effect is ascribed to the non-vanishing net orbital magnetic moment.Comment: Submitted to Phys. Rev.
Product-Group Unification in Type IIB String Thoery
The product-group unification is a model of unified theories, in which
masslessness of the two Higgs doublets and absence of dimension-five proton
decay are guaranteed by a symmetry. It is based on SU(5) x U(N) (N=2,3) gauge
group. It is known that various features of the model are explained naturally,
when it is embedded in a brane world. This article describes an idea of how to
accommodate all the particles of the model in Type IIB brane world. The
GUT-breaking sector is realized by a D3--D7 system, and chiral quarks and
leptons arise from intersection of D7-branes. The D-brane configuration can be
a geometric realization of the non-parallel family structure of quarks and
leptons, an idea proposed to explain the large mixing angles observed in the
neutrino oscillation. The tri-linear interaction of the next-to-minimal
supersymmetric standard model is obtained naturally in some cases.Comment: 33 pages, 5 figure
CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018
While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI
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