315,732 research outputs found
On the hydrostatic approximation of the Navier-Stokes equations in a thin strip
In this paper, we first prove the global well-posedness of a scaled
anisotropic Navier-Stokes system and the hydrostatic Navier-Stokes system in a
2-D striped domain with small analytic data in the tangential variable. Then we
justify the limit from the anisotropic Navier-Stokes system to the hydrostatic
Navier-Stokes system with analytic data
Different steady states for spin currents in noncollinear multilayers
We find there are at least two different steady states for transport across
noncollinear magnetic multilayers. In the conventional one there is a
discontinuity in the spin current across the interfaces which has been
identified as the source of current induced magnetic reversal; in the one
advocated herein the spin torque arises from the spin accumulation transverse
to the magnetization of a magnetic layer. These two states have quite different
attributes which should be discerned by current experiments.Comment: 8 pages, no figure. Accepted for publication in Journal of Physics:
Condensed Matte
Wigner-Souriau translations and Lorentz symmetry of chiral fermions
Chiral fermions can be embedded into Souriau's massless spinning particle
model by "enslaving" the spin, viewed as a gauge constraint. The latter is not
invariant under Lorentz boosts; spin enslavement can be restored, however, by a
subsequent Wigner-Souriau (WS) translation, analogous to a compensating gauge
transformation. The combined transformation is precisely the recently uncovered
twisted boost, which we now extend to finite transformations. WS-translations
are identified with the stability group of a motion acting on the right on the
Poincare group, whereas the natural Poincare action corresponds to action on
the left. The relation to non-commutative mechanics is explained.Comment: v3: a new Section explaining the relation to non-commutativity is
added. 14 pages, 2 figure
Controlled splitting of an atomic wave packet
We propose a simple scheme capable of adiabatically splitting an atomic wave
packet using two independent translating traps. Implemented with optical dipole
traps, our scheme allows a high degree of flexibility for atom interferometry
arrangements and highlights its potential as an efficient and high fidelity
atom optical beam splitter.Comment: 4 pages, 4 figures. Accepted by Phys. Rev. Let
Exotic Hill Problem: Hall motions and symmetries
Our previous study of a system of bodies assumed to move along almost
circular orbits around a central mass, approximately described by Hill's
equations, is extended to "exotic" [alias non-commutative] particles. For a
certain critical value of the angular velocity, the only allowed motions follow
the Hall law. Translations and generalized boosts span two independent
Heisenberg algebras with different central parameters. In the critical case,
the symmetry reduces to a single Heisenberg algebra.Comment: RevTeX, 4 pages, 4 figure
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