120,625 research outputs found
Numerical benchmarking of fluid-rigid body interactions
We propose a fluid-rigid body interaction benchmark problem, consisting of a
solid spherical obstacle in a Newtonian fluid, whose centre of mass is fixed
but is free to rotate. A number of different problems are defined for both two
and three spatial dimensions. The geometry is chosen specifically, such that
the fluid-solid partition does not change over time and classical fluid solvers
are able to solve the fluid-structure interaction problem. We summarise the
different approaches used to handle the fluid-solid coupling and numerical
methods used to solve the arising problems. The results obtained by the
described methods are presented and we give reference intervals for the
relevant quantities of interest
Quantization of systems with internal degrees of freedom in two-dimensional manifolds
Presented is a primary step towards quantization of infinitesimal rigid body
moving in a two-dimensional manifold. The special stress is laid on spaces of
constant curvature like the two-dimensional sphere and pseudosphere
(Lobatschevski space). Also two-dimensional torus is briefly discussed as an
interesting algebraic manifold.Comment: 19 page
Competing states for the fractional quantum Hall effect in the 1/3-filled second Landau level
In this work, we investigate the nature of the fractional quantum Hall state
in the 1/3-filled second Landau level (SLL) at filling factor (and
8/3 in the presence of the particle-hole symmetry) via exact diagonalization in
both torus and spherical geometries. Specifically, we compute the overlap
between the exact 7/3 ground state and various competing states including (i)
the Laughlin state, (ii) the fermionic Haffnian state, (iii) the
antisymmetrized product state of two composite fermion seas at 1/6 filling, and
(iv) the particle-hole (PH) conjugate of the parafermion state. All these
trial states are constructed according to a guiding principle called the
bilayer mapping approach, where a trial state is obtained as the
antisymmetrized projection of a bilayer quantum Hall state with interlayer
distance as a variational parameter. Under the proper understanding of the
ground-state degeneracy in the torus geometry, the parafermion state can
be obtained as the antisymmetrized projection of the Halperin (330) state.
Similarly, it is proved in this work that the fermionic Haffnian state can be
obtained as the antisymmetrized projection of the Halperin (551) state. It is
shown that, while extremely accurate at sufficiently large positive Haldane
pseudopotential variation , the Laughlin state loses its
overlap with the exact 7/3 ground state significantly at . At slightly negative , it is shown that the
PH-conjugated parafermion state has a substantial overlap with the exact
7/3 ground state, which is the highest among the above four trial states.Comment: 22 pages, 5 figure
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