13,800 research outputs found
Weighted Modal Transition Systems
Specification theories as a tool in model-driven development processes of
component-based software systems have recently attracted a considerable
attention. Current specification theories are however qualitative in nature,
and therefore fragile in the sense that the inevitable approximation of systems
by models, combined with the fundamental unpredictability of hardware
platforms, makes it difficult to transfer conclusions about the behavior, based
on models, to the actual system. Hence this approach is arguably unsuited for
modern software systems. We propose here the first specification theory which
allows to capture quantitative aspects during the refinement and implementation
process, thus leveraging the problems of the qualitative setting.
Our proposed quantitative specification framework uses weighted modal
transition systems as a formal model of specifications. These are labeled
transition systems with the additional feature that they can model optional
behavior which may or may not be implemented by the system. Satisfaction and
refinement is lifted from the well-known qualitative to our quantitative
setting, by introducing a notion of distances between weighted modal transition
systems. We show that quantitative versions of parallel composition as well as
quotient (the dual to parallel composition) inherit the properties from the
Boolean setting.Comment: Submitted to Formal Methods in System Desig
Two-photon transport through a waveguide coupling to a whispering gallery resonator containing an atom and photon-blockade effect
We investigate the two-photon transport through a waveguide side-coupling to
a whispering-gallery-atom system. Using the Lehmann-Symanzik-Zimmermann (LSZ)
reduction approach, we present the general formula for the two-photon processes
including the two-photon scattering matrices, the wavefunctions and the second
order correlation functions of the out-going photons. Based on the exact
results of the second order correlation functions, we analyze the quantum
statistics behaviors of the out-going photons for two different cases: (a) the
ideal case without the inter-modal coupling in the whispering gallery
resonator; (b) the case in the presence of the inter-modal coupling which leads
to more complex nonlinear behavior. In the ideal case, we show that the system
consists of two independent scattering pathways, a free pathway by a cavity
mode without atomic excitation, and a "Jaynes-Cummings" pathway described by
the Jaynes-Cummings Hamiltonian of a single-mode cavity coupling to an atom.
The free pathway does not contribution to correlated two-photon processes. In
the presence of intermodal mixing, the system no longer exhibit a free resonant
pathway. Instead, both the single-photon and the two photon transport
properties depend on the position of the atom. Thus, in the presence of
intermodal mixing one can in fact tune the photon correlation properties by
changing the position of the atom. Our formalism can be used to treat resonator
and cavity dissipation as well.Comment: 9 pages, 7 figure
The non-relativistic limit of (central-extended) Poincare group and some consequences for quantum actualization
The nonrelativistic limit of the centrally extended Poincar\'e group is
considered and their consequences in the modal Hamiltonian interpretation of
quantum mechanics are discussed [ O. Lombardi and M. Castagnino, Stud. Hist.
Philos. Mod. Phys 39, 380 (2008) ; J. Phys, Conf. Ser. 128, 012014 (2008) ].
Through the assumption that in quantum field theory the Casimir operators of
the Poincar\'e group actualize, the nonrelativistic limit of the latter group
yields to the actualization of the Casimir operators of the Galilei group,
which is in agreement with the actualization rule of previous versions of modal
Hamiltonian interpretation [ Ardenghi et al., Found. Phys. (submitted)
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