710 research outputs found
Thermofield-Bosonization on Compact Space
We develop the construction of fermionic fields in terms of bosonic ones to
describe free and interaction models in the circle, using thermofielddynamics.
The description in the case of finite temperature is developed for both normal
modes and zero modes. The treatment extends the thermofield-bosonization for
periodic space
Two-Dimensional Order and Disorder Thermofields
The main objective of this paper was to obtain the two-dimensional order and
disorder thermal operators using the Thermofield Bosonization formalism. We
show that the general property of the two-dimensional world according with the
bosonized Fermi field at zero temperature can be constructed as a product of an
order and a disorder variables which satisfy a dual field algebra holds at
finite temperature. The general correlation functions of the order and disorder
thermofields are obtained.Comment: 4 page
Autonomous Driving in Highway Scenarios through Artificial Potential Fields and Model Predictive Control
An approach for automated driving in highway scenarios in the context of a two levels hierarchical architecture is proposed. In particular, we define suitable artificial potential functions (APF) combinations that can effectively handle the most relevant maneuvers of highway driving, such as speed and distance tracking, lane keeping, overtaking and returning. Parameters of the APF functions are dynamically tuned according to the acquired scenario. The defined APF are included in the cost function of a Model Predictive Control (MPC) control problem to generate the path trajectory. A behavioral logic described by a finite state machine (FSM), based on sensor acquired data and suitable dynamic conditions is defined to select the most appropriate maneuver to realize. Extensive simulation tests are introduced to show the effectiveness of the proposed approach
Origin of long-period Alfv{\'e}n waves in the solar wind
We suggest that the observed long-period Alfv{\'e}n waves in the solar wind
may be generated in the solar interior due to the pulsation of the Sun in the
fundamental radial mode. The period of this pulsation is about 1 hour. The
pulsation causes a periodical variation of density and large-scale magnetic
field, this affecting the Alfv{\'e}n speed in the solar interior. Consequently
the Alfv{\'e}n waves with the half frequency of pulsation (i.e. with the double
period) can be parametrically amplified in the interior below the convection
zone due to the recently suggested swing wave-wave interaction. Therefore the
amplified Alfv{\'e}n waves have periods of several hours. The waves can
propagate upwards through the convection zone to the solar atmosphere and cause
the observed long-period Alfv{\'e}n oscillations in the solar wind.Comment: 5 pages, 2 figures, accepted in MNRAS Letter
Higher-Derivative Two-Dimensional Massive Fermion Theories
We consider the canonical quantization of a generalized two-dimensional
massive fermion theory containing higher odd-order derivatives. The
requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence
of tachyon excitations suffice to fix the mass term, which contains a
derivative coupling. We show that the basic quantum excitations of a
higher-derivative theory of order 2N+1 consist of a physical usual massive
fermion, quantized with positive metric, plus 2N unphysical massless fermions,
quantized with opposite metrics. The positive metric Hilbert subspace, which is
isomorphic to the space of states of a massive free fermion theory, is selected
by a subsidiary-like condition. Employing the standard bosonization scheme, the
equivalent boson theory is derived. The results obtained are used as a
guideline to discuss the solution of a theory including a current-current
interaction.Comment: 23 pages, Late
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