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تسجيل مستخدم جديدHall Viscosity of the Composite-Fermion Fermi Seas for Fermions and Bosons
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Songyang Pu
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The Hall viscosity has been proposed as a topological property of incompressible fractional quantum Hall states and can be evaluated as Berry curvature. This paper reports on the Hall viscosities of composite-fermion Fermi seas at $ u=1/m$, where $m$ is even for fermions and odd for bosons. A well-defined value for the Hall viscosity is not obtained by viewing the $1/m$ composite-fermion Fermi seas as the $nrightarrow infty$ limit of the Jain $ u=n/(nmpm 1)$ states, whose Hall viscosities $(pm n+m)hbar rho/4$ ($rho$ is the two-dimensional density) approach $pm infty$ in the limit $nrightarrow infty$. A direct calculation shows that the Hall viscosities of the composite-fermion Fermi sea states are finite, and also relatively stable with system size variation, although they are not topologically quantized in the entire $tau$ space. I find that the $ u=1/2$ composite-fermion Fermi sea wave function for a square torus yields a Hall viscosity that is expected from particle-hole symmetry and is also consistent with the orbital spin of $1/2$ for Dirac composite fermions. I compare my numerical results with some theoretical conjectures.
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