158,077 research outputs found
Darboux transformations for a twisted derivation and quasideterminant solutions to the super KdV equation
This paper is concerned with a generalized type of Darboux transformations
defined in terms of a twisted derivation satisfying
where is a homomorphism. Such twisted derivations include regular
derivations, difference and -difference operators and superderivatives as
special cases. Remarkably, the formulae for the iteration of Darboux
transformations are identical with those in the standard case of a regular
derivation and are expressed in terms of quasideterminants. As an example, we
revisit the Darboux transformations for the Manin-Radul super KdV equation,
studied in Q.P. Liu and M. Ma\~nas, Physics Letters B \textbf{396} 133--140,
(1997). The new approach we take enables us to derive a unified expression for
solution formulae in terms of quasideterminants, covering all cases at once,
rather than using several subcases. Then, by using a known relationship between
quasideterminants and superdeterminants, we obtain expressions for these
solutions as ratios of superdeterminants. This coincides with the results of
Liu and Ma\~nas in all the cases they considered but also deals with the one
subcase in which they did not obtain such an expression. Finally, we obtain
another type of quasideterminant solutions to the Main-Radul super KdV equation
constructed from its binary Darboux transformations. These can also be
expressed as ratios of superdeterminants and are a substantial generalization
of the solutions constructed using binary Darboux transformations in earlier
work on this topic
Nodeless superconductivity in Ca3Ir4Sn13: evidence from quasiparticle heat transport
We report resistivity and thermal conductivity measurements
on CaIrSn single crystals, in which superconductivity with K was claimed to coexist with ferromagnetic spin-fluctuations. Among
three crystals, only one crystal shows a small hump in resistivity near 20 K,
which was previously attributed to the ferromagnetic spin-fluctuations. Other
two crystals show the Fermi-liquid behavior at low temperature.
For both single crystals with and without the resistivity anomaly, the residual
linear term is negligible in zero magnetic field. In low fields,
shows a slow field dependence. These results demonstrate that
the superconducting gap of CaIrSn is nodeless, thus rule out
nodal gap caused by ferromagnetic spin-fluctuations.Comment: 5 pages, 4 figure
On solutions to the non-Abelian Hirota-Miwa equation and its continuum limits
In this paper, we construct grammian-like quasideterminant solutions of a
non-Abelian Hirota-Miwa equation. Through continuum limits of this non-Abelian
Hirota-Miwa equation and its quasideterminant solutions, we construct a cascade
of noncommutative differential-difference equations ending with the
noncommutative KP equation. For each of these systems the quasideterminant
solutions are constructed as well.Comment: 9 pages, 1 figur
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