arXiv subjects

C. Villavicencio

Publications and source records attributed to C. Villavicencio.

24 records · Page 2Linked to original sources

arXiv2006

Diagrammatics of the Dimensionally Reduced Action in phi^4 theory

We describe the Feynman rules for the construction of the Dimensionally Reduced Action (DRA) for a phi^4 field theory, as well as rules for the construction of the connected Green functions and the Dimensionally Reduced Effective Action (DREA), the effective action obtained from the DRA. Two and four-point connected Green functions are calculated to illustrate the application of those rules, and to exhibit the subtraction of UV divergences. As the DRA formalism expands about a background field, instead of the high temperature expansion obtained in the usual dimensional reduced field theory, we derive an expansion that is defined for all range of temperatures. We make a low temperature analysis of the DREA by considering soft modes. In particular, we study the case of near zero mass.

hep-ph↗

arXiv2005

Chiral dynamics and pion properties at finite temperature and isospin chemical potential

The thermal and density corrections, in terms of the isospin chemical potential $\mui $, to the mass of the pions, the decay constant and different condensates are studied in the framework of the SU(2) low energy effective chiral lagrangian at finite temperature in the two phases: The first phase $|\mui| m$, being $m$ the tree-level pion mass. As a function of temperature for $\mui =0$, the mass remains quite stable, starting to grow for very high values of $T$, confirming previous results. However, there are interesting corrections to the mass when both effects (temperature and chemical potential) are simultaneously present. At zero temperature the $π^{\pm}$ should condense when $\mui = \pm m_π$. At finite $T$, the condensed pion acquires a thermal mass in such a way that a mixture, like in a superfluid, of a condensed and normal phase appears.

hep-ph↗

arXiv2005

Two-flavor condensates in chiral dynamics: temperature and isospin density effects

Isospin density and thermal corrections for several condensates are discussed, at the one-loop level, in the frame of chiral dynamics with pionic degrees of freedom. The evolution of such objects give an additional insight into the condensed-pion phase transition, that occurs basically when $|\mui|>m_π$, being $|\mui|$ the isospin chemical potential. Calculations are done in both phases, showing a good agreement with lattice results for such condensates.

hep-ph↗

arXiv2004

Thermal pion masses in the second phase: $|μ_{I}| >m_π$

Density and thermal corrections to the mass of the pions are studied in the framework of the SU(2) low energy effective chiral lagrangian, in terms of the isospin chemical potential $μ_\tin{I}$. We concentrate the discussion in the region where the isospin chemical potential (absolute value) becomes bigger than the pion mass at zero temperature and density, i.e. in the phase where the condensed $π^-$ phase appears (for negative chemical potential). We are able to calculate the thermal and density evolution of masses in the limits where $|μ_{I}|\gg m$ and where $|μ_{I}| \gtrsim m$. We also identified the phase transition curve.

hep-ph↗

arXiv2003

Thermal Pions at Finite Isospin Chemical Potential

The density corrections, in terms of the isospin chemical potential $μ_I$, to the mass of the pions are studied in the framework of the SU(2) low energy effective chiral lagrangian. The pion decay constant $f_π(T, μ_{I})$ is also analized. As a function of temperature for $μ_I =0$, the mass remains quite stable, starting to grow for very high values of $T$, confirming previous results. However, there are interesting corrections to the mass when both effects (temperature and chemical potential) are simultaneously present. At zero temperature the $π^{\pm}$ should condensate when $μ_{I} = \mp m_π$. This is not longer valid anymore at finite $T$. The mass of the $π_0$ acquires also a non trivial dependence on $μ_I$ due to the finite temperature.

hep-ph↗

arXiv2002

Thermal Pions ns Isospin Chemical Potential Effects

The density corrections, in terms of the isospin chemical potential $μ_I$, to the mass of the pions are investigated in the framework of the SU(2) low energy effective chiral invariant lagrangian. As a function of temperature and $μ_I =0$, the mass remains quite stable, starting to grow for very high values of $T$, confirming previous results. However, the dependence for a non-vanishing chemical potential turns out to be much more dramatic. In particular, there are interesting corrections to the mass when both effects (temperature and chemical potential) are simultaneously present. At zero temperature the $π^{\pm}$ should condensate when $μ_{I} = \mp m_π$. This is not longer valid anymore at finite $T$. The mass of the $π_0$ acquires also a non trivial dependence on $μ_I$ at finite $T$.

hep-ph↗