4,757 research outputs found
A mechanical switch for state transfer in dual cavity optomechanical systems
Dual cavity opto-electromechanical systems (OEMS) are those where two
electromagnetic cavities are connected by a common mechanical spring. These
systems have been shown to facilitate high fidelity quantum state transfer from
one cavity to another. In this paper, we explicitly calculate the effect on the
fidelity of state transfer, when an additional spring is attached to only one
of the cavities. Our quantitative estimates of loss of fidelity, highlight the
sensitivity of dual cavity OEMS when it couples to additional mechanical modes.
We show that this sensitivity can be used to design an effective mechanical
switch, for inhibition or high fidelity transmission of quantum states between
the cavities.Comment: Accepted in Physical Review
Boosting as a Product of Experts
In this paper, we derive a novel probabilistic model of boosting as a Product
of Experts. We re-derive the boosting algorithm as a greedy incremental model
selection procedure which ensures that addition of new experts to the ensemble
does not decrease the likelihood of the data. These learning rules lead to a
generic boosting algorithm - POE- Boost which turns out to be similar to the
AdaBoost algorithm under certain assumptions on the expert probabilities. The
paper then extends the POEBoost algorithm to POEBoost.CS which handles
hypothesis that produce probabilistic predictions. This new algorithm is shown
to have better generalization performance compared to other state of the art
algorithms
A comparative study of overlap and staggered fermions in QCD
We perform a comparative study of the infrared properties of overlap and
staggered fermions in QCD. We observe that the infrared spectrum of the APE/HYP
improved staggered Dirac operator develops a four-fold near-degeneracy and is
in quantitative agreement with the infrared spectrum of the overlap operator.
The near-degeneracy allows us to identify the zero modes of the staggered
operator and we find that the number of zero modes is in line with the
topological index of the overlap operator.Comment: Talk presented at Lattice2004(chiral), Fermilab, June 21-26, 2004, 3
pages, 2 figure
Chiral Symmetry Restoration in the Schwinger Model with Domain Wall Fermions
Domain Wall Fermions utilize an extra space time dimension to provide a
method for restoring the regularization induced chiral symmetry breaking in
lattice vector gauge theories even at finite lattice spacing. The breaking is
restored at an exponential rate as the size of the extra dimension increases.
Before this method can be used in dynamical simulations of lattice QCD, the
dependence of the restoration rate to the other parameters of the theory and,
in particular, the lattice spacing must be investigated. In this paper such an
investigation is carried out in the context of the two flavor lattice Schwinger
model.Comment: LaTeX, 37 pages including 18 figures. Added comments regarding power
law fitting in sect 7. Also, few changes were made to elucidate the content
in sect. 5.1 and 5.3. To appear in Phys. Rev.
The overlap operator as a continued fraction
We use a continued fraction expansion of the sign-function in order to obtain
a five dimensional formulation of the overlap lattice Dirac operator. Within
this formulation the inverse of the overlap operator can be calculated by a
single Krylov space method where nested conjugate gradient procedures are
avoided. We show that the five dimensional linear system can be made well
conditioned using equivalence transformations on the continued fractions. This
is of significant importance when dynamical overlap fermions are simulated.Comment: 3 pages, 1 figure, talk presented by U. Wenger at Lattice2001(chiral
Kernel Carpentry for Online Regression using Randomly Varying Coefficient Model
We present a Bayesian formulation of locally weighted learning (LWL) using the novel concept of a randomly varying coefficient model. Based on thi
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