5,475 research outputs found
Nonlinear morphoelastic plates II: exodus to buckled states
Morphoelasticity is the theory of growing elastic materials. This theory is based on the multiple decomposition of the deformation gradient and provides a formulation of the deformation and stresses induced by growth. Following a companion paper, a general theory of growing nonlinear elastic Kirchhoff plate is described. First, a complete geometric description of incompatibility with simple examples is given. Second, the stability of growing Kirchhoff plates is analyzed
Organised crime and public sector corruption
Foreword: In 2006, the Australian Government introduced the Anti-money Laundering and Counter-Terrorism Financing Act 2006 (Cth) which increased regulatory controls over businesses potentially able to facilitate organised criminal activities such as money laundering. The implementation of tougher legislation and associated law enforcement interventions may result in criminal organisations adjusting their tactics in order to continue their activities without detection. In this paper, the risk and potential impact of tactical displacement by organised criminals is discussed with regard to the potential for increased attempts by organised crime groups to corrupt public servants. There is a paucity of research exploring the nature and extent of public sector corruption committed by organised crime groups. This discussion is informed by literature on ‘crime scripts’ originally developed by Cornish (1994) and the 5I’s crime prevention framework developed by Ekblom (2011). Making use of public-source information about the commission of such crimes, as exemplified in two recent corruption cases, some intervention strategies are proposed that may be effective in reducing the risks of corruption of public sector officials by organised crime groups in Australia
Another integrable case in the Lorenz model
A scaling invariance in the Lorenz model allows one to consider the usually
discarded case sigma=0. We integrate it with the third Painlev\'e function.Comment: 3 pages, no figure, to appear in J. Phys.
The role of quantum fluctuations in the optomechanical properties of a Bose-Einstein condensate in a ring cavity
We analyze a detailed model of a Bose-Einstein condensate trapped in a ring
optical resonator and contrast its classical and quantum properties to those of
a Fabry-P{\'e}rot geometry. The inclusion of two counter-propagating light
fields and three matter field modes leads to important differences between the
two situations. Specifically, we identify an experimentally realizable region
where the system's behavior differs strongly from that of a BEC in a
Fabry-P\'{e}rot cavity, and also where quantum corrections become significant.
The classical dynamics are rich, and near bifurcation points in the mean-field
classical system, the quantum fluctuations have a major impact on the system's
dynamics.Comment: 11 pages, 11 figures, submitted to PR
Manifestations of Drag Reduction by Polymer Additives in Decaying, Homogeneous, Isotropic Turbulence
The existence of drag reduction by polymer additives, well established for
wall-bounded turbulent flows, is controversial in homogeneous, isotropic
turbulence. To settle this controversy we carry out a high-resolution direct
numerical simulation (DNS) of decaying, homogeneous, isotropic turbulence with
polymer additives. Our study reveals clear manifestations of
drag-reduction-type phenomena: On the addition of polymers to the turbulent
fluid we obtain a reduction in the energy dissipation rate, a significant
modification of the fluid energy spectrum especially in the deep-dissipation
range, a suppression of small-scale intermittency, and a decrease in
small-scale vorticity filaments.Comment: 4 pages, 3 figure
Transport in Almost Integrable Models: Perturbed Heisenberg Chains
The heat conductivity kappa(T) of integrable models, like the one-dimensional
spin-1/2 nearest-neighbor Heisenberg model, is infinite even at finite
temperatures as a consequence of the conservation laws associated with
integrability. Small perturbations lead to finite but large transport
coefficients which we calculate perturbatively using exact diagonalization and
moment expansions. We show that there are two different classes of
perturbations. While an interchain coupling of strength J_perp leads to
kappa(T) propto 1/J_perp^2 as expected from simple golden-rule arguments, we
obtain a much larger kappa(T) propto 1/J'^4 for a weak next-nearest neighbor
interaction J'. This can be explained by a new approximate conservation law of
the J-J' Heisenberg chain.Comment: 4 pages, several minor modifications, title change
Adiabatic quantum computation along quasienergies
The parametric deformations of quasienergies and eigenvectors of unitary
operators are applied to the design of quantum adiabatic algorithms. The
conventional, standard adiabatic quantum computation proceeds along
eigenenergies of parameter-dependent Hamiltonians. By contrast, discrete
adiabatic computation utilizes adiabatic passage along the quasienergies of
parameter-dependent unitary operators. For example, such computation can be
realized by a concatenation of parameterized quantum circuits, with an
adiabatic though inevitably discrete change of the parameter. A design
principle of adiabatic passage along quasienergy is recently proposed: Cheon's
quasienergy and eigenspace anholonomies on unitary operators is available to
realize anholonomic adiabatic algorithms [Tanaka and Miyamoto, Phys. Rev. Lett.
98, 160407 (2007)], which compose a nontrivial family of discrete adiabatic
algorithms. It is straightforward to port a standard adiabatic algorithm to an
anholonomic adiabatic one, except an introduction of a parameter |v>, which is
available to adjust the gaps of the quasienergies to control the running time
steps. In Grover's database search problem, the costs to prepare |v> for the
qualitatively different, i.e., power or exponential, running time steps are
shown to be qualitatively different. Curiously, in establishing the equivalence
between the standard quantum computation based on the circuit model and the
anholonomic adiabatic quantum computation model, it is shown that the cost for
|v> to enlarge the gaps of the eigenvalue is qualitatively negligible.Comment: 11 pages, 2 figure
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