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Rafael Hurtado

Publications and source records attributed to Rafael Hurtado.

9 recordsLinked to original sources
arXiv2018

Interplay between musical practices and tuning in the marimba de chonta music

In the Pacific Coast of Colombia there is a type of marimba called marimba de chonta, which provides the melodic and harmonic contour for traditional music with characteristic chants and dances. The tunings of this marimba are based on the voice of female singers and allows musical practices, as a transposition that preserves relative distances between bars. Here we show that traditional tunings are consistent with isotonic scales, and that they have changed in the last three decades due to the influence of Western music. Specifically, low octaves have changed into just octaves. Additionally, consonance properties of this instrument include the occurrence of a broad minimum of dissonance that is used in the musical practices, while the narrow local peaks of dissonance are avoided. We found that the main reason for this is the occurrence of uncertainties in the tunings with respect to the mathematical successions of isotonic scales. We conclude that in this music the emergence of tunings and musical practices cannot be considered as separate issues. Consonance, timbre, and musical practices are entangled.

cs.SD↗
arXiv2017

Tonal consonance parameters link microscopic and macroscopic properties of music exposing a hidden order in melody

Consonance is related to the perception of pleasantness arising from a combination of sounds and has been approached quantitatively using mathematical relations, physics, information theory, and psychoacoustics. Tonal consonance is present in timbre, musical tuning, harmony, and melody, and it is used for conveying sensations, perceptions, and emotions in music. It involves the physical properties of sound waves and is used to study melody and harmony through musical intervals and chords. From the perspective of complexity, the macroscopic properties of a system with many parts frequently rely on the statistical properties of its constituent elements. Here we show how the tonal consonance parameters for complex tones can be used to study complexity in music. We apply this formalism to melody, showing that melodic lines in musical pieces can be described in terms of the physical properties of melodic intervals and the existence of an entropy extremalization principle subject to psychoacoustic macroscopic constraints with musical meaning. This result connects the human perception of consonance with the complexity of human creativity in music through the physical properties of the musical stimulus.

cs.SD↗
arXiv2014

Several Multiplexes in the same City: The role of wealth differences in urban mobility

In this work we analyze the architecture of real urban mobility networks from the multiplex perspective. In particular, based on empirical data about the mobility patterns in the cities of Bogotá and Medell\'ın, each city is represented by six multiplex networks, each one representing the origin-destination trips performed by a subset of the population corresponding to a particular socioeconomic status. The nodes of each multiplex are the different urban locations whereas links represent the existence of a trip from one node (origin) to another (destination). On the other hand, the different layers of each multiplex correspond to the different existing transportation modes. By exploiting the characterization of multiplex transportation networks combining different transportation modes, we aim at characterizing the mobility patterns of each subset of the population. Our results show that the socioeconomic characteristics of the population have an extraordinary impact in the layer organization of these multiplex systems.

physics.soc-ph↗
arXiv2005

Higgs boson decay in the large N limit

The Equivalence Theorem is commonly used to calculate perturbatively amplitudes involving gauge bosons at energy scales higher than gauge boson masses. However, when the scalar sector is strongly interacting the theory is non-perturbative. We show that the Equivalence Theorem holds in the large N limit at next-to-leading order by calculating the decay widths h -> W^{+}W^{-} and h->π^{+}π^{-}. We also show, in the same scheme of calculations, that unitarity is fulfilled for the process h->π^{+}π^{-}.

hep-ph↗
arXiv2000

Can large fermion chemical potentials suppress the electroweak phase transition ?

We calculate the critical temperature $(T_c$) of the electroweak phase transition in the minimal standard model considering simultaneously temperature ($T$) and fermion chemical potential ($μ_f$) effects over the effective potential. The calculation is performed in the one-loop approximation to the effective potential at non-zero temperature using the real time formalism of the thermal field theory. We show that it exists a fermion chemical potential critical value ($μ_f^c$) for which the Higgs boson condensate vanishes at T=0. If $T$ and $μ_f$ effects are considered simultaneously, it is shown that for $μ_f \geq μ_f^c$ then $T_c^2 \leq 0$, implying that the electroweak phase transition might not take place.

hep-ph↗
arXiv1999

Dispersion relations at finite temperature and density for nucleons and pions

We calculate the nucleonic and pionic dispersion relations at finite temperature T and non-vanishing chemical potentials $(μ_f)$ in the context of an effective chiral theory that describes the strong and electromagnetic interactions for nucleons and pions. The dispersion relations are calculated in the broken chiral symmetry phase, where the nucleons are massive and pions are taken as massless. The calculation is performed at lowest order in the energy expansion, working in the framework of the real time formalism of thermal field theory in the Feynman gauge. These one-loop dispersion relations are obtained at leading order with respect to T and $μ_f$. We also evaluate the effective masses of the quasi-nucleon and quasi-pion excitations in thermal and chemical conditions as the ones of a neutron star.

hep-ph↗
arXiv1998

Dispersion relations in Kbar N - pi Y coupled channel analyses

Rapidly convergent, unsubtracted dispersion relations have been used to test coupled channel analyses of low-energy S = -1 meson-baryon pi Y --> pi Y' channels. We conclude that the low-energy S = -1 meson-baryon sector is less well known than currently believed, and that it deserves more accurate experiments and analyses.

nucl-th↗
arXiv1998

$πY$ Phenomenology from $\bar KN$ Scattering

The dispersive determination of $π{Y}Σ$ coupling constants ($Y = Λ, Σ$) and the implications for low-energy $\bar{K}N$ analysis are discussed. (Presented by G. Violini at the "7th Int. Symp. on Meson-Nucleon Physics and the Structure of the Nucleon, MENU '97", Vancouver, B.C., July 28th - August 1st, 1977).

nucl-th↗