19,340 research outputs found
Universal quantum computation on a semiconductor quantum wire network
Universal quantum computation (UQC) using Majorana fermions on a 2D
topological superconducting (TS) medium remains an outstanding open problem.
This is because the quantum gate set that can be generated by braiding of the
Majorana fermions does not include \emph{any} two-qubit gate and also the
single-qubit phase gate. In principle, it is possible to create these
crucial extra gates using quantum interference of Majorana fermion currents.
However, it is not clear if the motion of the various order parameter defects
(vortices, domain walls, \emph{etc.}), to which the Majorana fermions are bound
in a TS medium, can be quantum coherent. We show that these obstacles can be
overcome using a semiconductor quantum wire network in the vicinity of an
-wave superconductor, by constructing topologically protected two-qubit
gates and any arbitrary single-qubit phase gate in a topologically unprotected
manner, which can be error corrected using magic state distillation. Thus our
strategy, using a judicious combination of topologically protected and
unprotected gate operations, realizes UQC on a quantum wire network with a
remarkably high error threshold of as compared to to
in ordinary unprotected quantum computation.Comment: 7 pages, 2 figure
Path Integral Approach to Residual Gauge Fixing
In this paper we study the question of residual gauge fixing in the path
integral approach for a general class of axial-type gauges including the
light-cone gauge. We show that the two cases -- axial-type gauges and the
light-cone gauge -- lead to very different structures for the explicit forms of
the propagator. In the case of the axial-type gauges, fixing the residual
symmetry determines the propagator of the theory completely. On the other hand,
in the light-cone gauge there is still a prescription dependence even after
fixing the residual gauge symmetry, which is related to the existence of an
underlying global symmetry.Comment: revtex 13pages, slightly expanded discussion, version to be published
in Physical Review
Solutions of Nonlinear Second Order Multi-point Boundary Value Problems by Homotopy Perturbation Method
In this paper, we present an algorithm for the numerical solution of the second order multi- point boundary value problem with suitable multi boundary conditions. The algorithm is based on the homotopy perturbation approach and the solutions are calculated in the form of a rapid convergent series. It is observed that the method gives more realistic series solutions that converge very rapidly in physical problems. Illustrative numerical examples are provided to demonstrate the efficiency and simplicity of the proposed method in solving this type of multipoint boundary value problems
Heavy Neutrinos and Lepton Flavour Violation in Left-Right Symmetric Models at the LHC
We discuss lepton flavour violating processes induced in the production and
decay of heavy right-handed neutrinos at the LHC. Such particles appear in
left-right symmetrical extensions of the Standard Model as the messengers of
neutrino mass generation, and can have masses at the TeV scale. We determine
the expected sensitivity on the right-handed neutrino mixing matrix, as well as
on the right-handed gauge boson and heavy neutrino masses. By comparing the
sensitivity of the LHC with that of searches for low energy LFV processes, we
identify favourable areas of the parameter space to explore the complementarity
between LFV at low and high energies.Comment: 34 pages, 16 figures, PRD versio
Composite fermion state of spin-orbit coupled bosons
We consider spinor Bose gas with the isotropic Rashba spin-orbit coupling in
2D. We argue that at low density its groundstate is a composite fermion state
with a Chern-Simons gauge field and filling factor one. The chemical potential
of such a state scales with the density as \mu \propto n^{3/2}. This is a lower
energy per particle than \mu \propto n for the earlier suggested groundstate
candidates: a condensate with broken time-reversal symmetry and a spin density
wave state.Comment: 15 pages, 7 figures, Revte
Sugar Cane Refining And Processing Company: A Comprehensive Case In Measuring A Firms Cost Of Capital
The Sugar Cane Refining and Processing Company is a comprehensive case illustrating how a firms financial manager should calculate the firms cost of capital. Senior level undergraduate and graduate corporate financial management courses cover advanced topics in cost of capital and applying the rate in capital budgeting. To cover this relevant topic in a single case, the invented or armchair approach is used. This case is completely contrived but is very educationally effective
Podridões em estacas de roseira, minirrosa e mussaendra no Estado do Ceará.
bitstream/CNPAT/10226/1/cot_129.pd
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