11,906 research outputs found
Automated Negotiation for Provisioning Virtual Private Networks Using FIPA-Compliant Agents
This paper describes the design and implementation of negotiating agents for the task of provisioning virtual private networks. The agents and their interactions comply with the FIPA specification and they are implemented using the FIPA-OS agent framework. Particular attention is focused on the design and implementation of the negotiation algorithms
Using Similarity Criteria to Make Negotiation Trade-Offs
This paper addresses the issues involved in software agents making trade-offs during automated negotiations in which they have information uncertainty and resource limitations. In particular, the importance of being able to make trade-offs in real-world applications is highlighted and a novel algorithm for performing trade-offs for multi-dimensional goods is developed. The algorithm uses the notion of fuzzy similarity in order to find negotiation solutions that are beneficial to both parties. Empirical results indicate the benefits and effectiveness of the trade-off algorithm in a range of negotiation situations
Infinite matrix product states, Conformal Field Theory and the Haldane-Shastry model
We generalize the Matrix Product States method using the chiral vertex
operators of Conformal Field Theory and apply it to study the ground states of
the XXZ spin chain, the J1-J2 model and random Heisenberg models. We compute
the overlap with the exact wave functions, spin-spin correlators and the Renyi
entropy, showing that critical systems can be described by this method. For
rotational invariant ansatzs we construct an inhomogenous extension of the
Haldane-Shastry model with long range exchange interactions.Comment: 5 pages, 4 figures, 1 reference adde
Long-range Heisenberg models in quasi-periodically driven crystals of trapped ions
We introduce a theoretical scheme for the analog quantum simulation of
long-range XYZ models using current trapped-ion technology. In order to achieve
fully-tunable Heisenberg-type interactions, our proposal requires a
state-dependent dipole force along a single vibrational axis, together with a
combination of standard resonant and detuned carrier drivings. We discuss how
this quantum simulator could explore the effect of long-range interactions on
the phase diagram by combining an adiabatic protocol with the quasi-periodic
drivings and test the validity of our scheme numerically. At the isotropic
Heisenberg point, we show that the long-range Hamiltonian can be mapped onto a
non-linear sigma model with a topological term that is responsible for its
low-energy properties, and we benchmark our predictions with
Matrix-Product-State numerical simulations.Comment: closer to published versio
Dualities in Spin Ladders
We introduce a set of discrete modular transformations and
in order to study the relationships between the different phases of
the Heisenberg ladders obtained with all possible exchange coupling constants.
For the 2 legged ladder we show that the phase is invariant under the
transformation, while the Haldane phase is invariant under .
These two phases are related by . Moreover there is a "mixed" phase,
that is invariant under , and which under becomes the RVB
phase, while under becomes the Haldane phase. For odd ladders there
exists only the transformation which, for strong coupling, maps the
effective antiferromagnetic spin 1/2 chain into the spin 3/2 chain.Comment: REVTEX file, 5 pages, 2 EPS figure
Experimental tests for the Babu-Zee two-loop model of Majorana neutrino masses
The smallness of the observed neutrino masses might have a radiative origin.
Here we revisit a specific two-loop model of neutrino mass, independently
proposed by Babu and Zee. We point out that current constraints from neutrino
data can be used to derive strict lower limits on the branching ratio of
flavour changing charged lepton decays, such as .
Non-observation of Br() at the level of would rule
out singly charged scalar masses smaller than 590 GeV (5.04 TeV) in case of
normal (inverse) neutrino mass hierarchy. Conversely, decay branching ratios of
the non-standard scalars of the model can be fixed by the measured neutrino
angles (and mass scale). Thus, if the scalars of the model are light enough to
be produced at the LHC or ILC, measuring their decay properties would serve as
a direct test of the model as the origin of neutrino masses.Comment: 14 pages, 16 figure
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