7,045 research outputs found
A new approach to the inverse problem for current mapping in thin-film superconductors
A novel mathematical approach has been developed to complete the inversion of
the Biot-Savart law in one- and two-dimensional cases from measurements of the
perpendicular component of the magnetic field using the well-developed
Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is
provided in great detail to allow a straightforward implementation as opposed
to those found in the literature. Our new approach also refines our previous
results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and
streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)]
deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys.
65, 361 (1989)]. We also verify and streamline the iterative technique, which
was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)]
to account for in-plane magnetic fields caused by the bending of the applied
magnetic field due to the demagnetising effect. After testing on
magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film,
we show that the procedure employed is effective
Efficient pricing options under regime switching
In the paper, we propose two new efficient methods for pricing barrier option in wide classes of LĆ©vy processes with/without regime switching. Both methods are based on the numerical Laplace transform inversion formulae and the Fast Wiener-Hopf factorization method developed in Kudryavtsev and Levendorski\v{i} (Finance Stoch. 13: 531--562, 2009). The first method uses the Gaver-Stehfest algorithm, the second one -- the Post-Widder formula. We prove the advantage of the new methods in terms of accuracy and convergence by using Monte-Carlo simulations.LĆ©vy processes; barrier options;regime switching models; Wiener-Hopf factorization; Laplace transform; numerical methods; numerical transform inversion
The inverse Laplace transform as the ultimate tool for transverse mass spectra
New high statistics data from the second generation of ultrarelativistic
heavy-ion experiments open up new possibilities in terms of data analysis. To
fully utilize the potential we propose to analyze the -spectra of
hadrons using the inverse Laplace transform. The problems with its inherent
ill-definedness can be overcome and several applications in other fields like
biology, chemistry or optics have already shown its feasability. Moreover, the
method also promises to deliver upper bounds on the total information content
of the spectra, which is of big importance for all other means of analysis.
Here we compute several Laplace inversions from different thermal scenarios,
both analytically and numerically, to test the efficiency of the method.
Especially the case of a two component structure, related to a possible first
order phase transition to a quark gluon plasma, is closer investigated and it
is shown that at least a signal to noise ratio of is necessary to
resolve two individual components.Comment: 13 pages (PostScript, including figures), BNL-NTHES
- ā¦