Shankar Ghosh

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Most materials freeze when cooled to sufficiently low temperature. We find that magnetic dipoles randomly distributed in a solid matrix condense into a spin liquid with spectral properties on cooling that are the diametric opposite of those for conventional glasses. Measurements of the nonlinear magnetic dynamics in the low-temperature liquid reveal the(More)
The thermal effects of laser–induced plasma on isotropic turbulence are studied using direct numerical simulation. Laminar and turbulent simulations are conducted. For the laminar simulations, a tear–drop shaped blast wave propagates into the background becoming spherical in time. Shock radius and jumps in fluid properties at the shock front are compared to(More)
Most physical and biological systems are disordered, even though the majority of theoretical models treat disorder as a weak perturbation. One particularly simple system is a ferromagnet approaching its Curie temperature, T(C), where all of the spins associated with partially filled atomic shells acquire parallel orientation. With the addition of disorder(More)
Motivated by the experimental demonstration of the actuator action of single-walled carbon nanotubes and in situ resonance Raman experiments, we have performed ab initio restricted Hatree–Fock calculations of the electronic structure of a (5,5) single-walled nanotube in the presence of various ions. We show that the presence of ions near the nanotube causes(More)
The inability of systems of interacting objects to satisfy all constraints simultaneously leads to frustration. A particularly important consequence of frustration is the ability to access certain protected parts of a system without disturbing the others. For magnets such "protectorates" have been inferred from theory and from neutron scattering, but their(More)
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