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991.
A. Medhi S. Basu C. Kadolkar 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,72(4):583-589
The phase diagram for a t-J bilayer as a function of interplanar
hopping, t⊥ and hole concentration, x is presented for a few different
values of interplanar exchange, J⊥ using variational Monte Carlo
calculations. The phase diagram shows rich features, such as a coexistence of
antiferromagnetism and superconductivity at underdoping, planar (d-wave) and
interplanar (dz-wave) superconducting correlations for small and large
J⊥, respectively at optimal and overdoping.
Another unusual feature appears in the form of a dome shaped structure in the phase
diagram where the superconducting correlations
are initially assisted as interplanar hopping is enhanced for small
t⊥, while larger t⊥ is found to be detrimental to
superconductivity. 相似文献
992.
993.
994.
Tapobrata Sarkar Rahul Basu 《The European Physical Journal C - Particles and Fields》1998,5(3):493-500
In this paper we check the validity of the ideas of double scaling as given by Ball and Forte in a semi inclusive process
like production at HERA, in different kinematical regions, for low values of the Bjorken variable . In particular, we study production in the inelastic and diffractive (elastic) regimes using the double scaling form of the gluon distribution functions.
We compare these predictions with data (wherever available) and with other standard parameterisations. We find that double
scaling holds in the inelastic regime over a larger kinematic region than that given by the analysis of the proton structure
function . However, in the diffractive region, double scaling seems to suggest an admixture of hard pomeron boundary conditions for
the gluon distribution, while predicting a steeper rise in the cross section than suggested by present data.
Received: 17 December 1997 / Published online: 10 March 1998 相似文献
995.
We report the magnetic proximity effect in a ferrimagnetic Fe(3)O(4) core/ferrimagnetic γ-Mn(2)O(3) shell nanoparticle system, in terms of an enhancement of the Curie temperature (T(c)) of the γ-Mn(2)O(3) shell (~66 K) compared to its bulk value (~40 K), and the presence of magnetic ordering in its so-called paramagnetic region (i.e. above 66 K). The ferrimagnetic nature of both core and shell has been found from a neutron diffraction study. The origin of these two features of the magnetic proximity effect has been ascribed to the proximity of the γ-Mn(2)O(3) shell with a high-T(c) Fe(3)O(4) core (~858 K in bulk form) and an interface exchange coupling between core and shell. Interestingly, we did not observe any exchange bias effect, which has been interpreted as a signature of a weak interface exchange coupling between core and shell. The present study brings out the importance of the relative strength of the interface coupling in governing the simultaneous occurrence of the magnetic proximity effect and the exchange bias phenomenon in a single system. 相似文献
996.
A. Basu J.K. Bhattacharjee S. Ramaswamy 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(4):725-730
We show that a recently proposed [J. Fleischer, P.H. Diamond, Phys. Rev. E 58, R2709 (1998)] one-dimensional Burgers-like model for magnetohydrodynamics (MHD) is in effect identical to existing models
for drifting lines and sedimenting lattices. We use the model to demonstrate, contrary to claims in the literature, that the
energy spectrum of MHD turbulence should be independent of mean magnetic field and that cross-correlations between the noise
sources for the velocity and magnetic fields cannot change the structure of the equations under renormalisation. We comment
on the scaling and the multiscaling properties of the stochastically forced version of the model.
Received 29 October 1998 and Received in final form 8 December 1998 相似文献
997.
Sourendu Gupta D Indumathi S Banerjee R Basu M Dittmar RV Gavai F Gelis D Ghosh Sourendu Gupta D Indumathi Asmita Mukherjee 《Pramana》2000,55(1-2):327-333
This is the report of the QCD working group at WHEPP-6. Discussions and work on heavy ion collisions, polarized scattering,
and collider phenomenology are reported. 相似文献
998.
We develop foundational tools for classifying the extreme valid functions for the k-dimensional infinite group problem. In particular, we present the general regular solution to Cauchy’s additive functional equation on restricted lower-dimensional convex domains. This provides a k-dimensional generalization of the so-called Interval Lemma, allowing us to deduce affine properties of the function from certain additivity relations. Next, we study the discrete geometry of additivity domains of piecewise linear functions, providing a framework for finite tests of minimality and extremality. We then give a theory of non-extremality certificates in the form of perturbation functions. We apply these tools in the context of minimal valid functions for the two-dimensional infinite group problem that are piecewise linear on a standard triangulation of the plane, under a regularity condition called diagonal constrainedness. We show that the extremality of a minimal valid function is equivalent to the extremality of its restriction to a certain finite two-dimensional group problem. This gives an algorithm for testing the extremality of a given minimal valid function. 相似文献
999.
1000.
Tepper L. Gill Sudeshna Basu Woodford W. Zachary V. Steadman 《Proceedings of the American Mathematical Society》2004,132(5):1429-1434
In this paper we show that a result of Gross and Kuelbs, used to study Gaussian measures on Banach spaces, makes it possible to construct an adjoint for operators on separable Banach spaces. This result is used to extend well-known theorems of von Neumann and Lax. We also partially solve an open problem on the existence of a Markushevich basis with unit norm and prove that all closed densely defined linear operators on a separable Banach space can be approximated by bounded operators. This last result extends a theorem of Kaufman for Hilbert spaces and allows us to define a new metric for closed densely defined linear operators on Banach spaces. As an application, we obtain a generalization of the Yosida approximator for semigroups of operators.