Lyapunov Exponent and the Solid-Fluid Phase Transition

We study changes in the chaotic properties of a many-body system undergoing a solid-fluid phase transition. To do this, we compute the temperature dependence of the largest Lyapunov exponents $\lambda_{max}$ for both two- and three-dimensional periodic systems of $N$-particles for various densities. The particles interact through a soft-core potential. The two-dimensional system exhibits an apparent second-order phase transition as indicated by a $\lambda$-shaped peak in the specific heat. The first derivative of $\lambda_{max}$ with respect to the temperature shows a peak at the same temperature. The three-dimensional system shows jumps, in both system energy and $\lambda_{max}$, at the same temperature, suggesting a first-order phase transition. Relaxation phenomena in the phase-transition region are analyzed by using the local time averages.Comment: 16 pages, REVTeX, 10 eps figures, epsfig.st

Kaon-Soliton Bound State Approach to the Pentaquark States

We show that in hidden local symmetry theory with the vector manifestation (VM), a K^+ can be bound to skyrmion to give the Theta^+ pentaquark with spin 1/2 and even parity which is consistent with large N_c counting. The vector meson K^* subject to the VM in the chiral limit plays an essential role in inducing the binding.Comment: Change of title, erroneous statements, e.g., re: interpretation of the widths, corrected, results remain unmodifie

Kaons in Dense Half-Skyrmion Matter

Dense hadronic matter at low temperature is expected to be in crystal and at high density make a transition to a {\em chirally restored but color-confined} state which is a novel phase hitherto unexplored. This phase transition is predicted in both skyrmion matter in 4D and instanton matter in 5D, the former in the form of half-skyrmions and the latter in the form of half-instantons or dyons. We predict that when $K^-$'s are embedded in this half-skyrmion or half-instanton (dyonic) matter which may be reached not far above the normal density, there arises an enhanced attraction from the soft dilaton field figuring for the trace anomaly of QCD and the Wess-Zumino term. This attraction may have relevance for a possible strong binding of anti-kaons in dense nuclear matter and for kaon condensation in neutron-star matter. Such kaon property in the half-skyrmion phase is highly non-perturbarive and may not be accessible by low-order chiral perturbation theory. Relevance of the half-skyrmion or dyonic matter to compact stars is discussed.Comment: 5 pages, 2 figure

The Inhomogeneous Phase of Dense Skyrmion Matter

It was predicted qualitatively in ref.[1] that skyrmion matter at low density is stable in an inhomogeneous phase where skyrmions condensate into lumps while the remaining space is mostly empty. The aim of this paper is to proof quantitatively this prediction. In order to construct an inhomogeneous medium we distort the original FCC crystal to produce a phase of planar structures made of skyrmions. We implement mathematically these planar structures by means of the 't Hooft instanton solution using the Atiyah-Manton ansatz. The results of our calculation of the average density and energy confirm the prediction suggesting that the phase diagram of the dense skyrmion matter is a lot more complex than a simple phase transition from the skyrmion FCC crystal lattice to the half-skyrmion CC one. Our results show that skyrmion matter shares common properties with standard nuclear matter developing a skin and leading to a binding energy equation which resembles the Weiszaecker mass formula.Comment: 8 figures, 14 page

Skyrmion approach to finite density and temperature

We review an approach, developed over the past few years, to describe hadronic matter at finite density and temperature, whose underlying theoretical framework is the Skyrme model, an effective low energy theory rooted in large $N_c$ QCD. In this approach matter is described by various crystal structures of skyrmions, classical topological solitons carrying baryon number, from which conventional baryons appear by quantization. Chiral and scale symmetries play a crucial role in the dynamics as described by pion, dilaton and vector meson degrees of freedom. When compressed or heated skyrmion matter describes a rich phase diagram which has strong connections with the confinement/deconfinement phase transition.Comment: To appear in "The Multifaceted Skyrmion" (World Scientific) ed. G.E. Brown and M. Rh

Magnetic moments of heavy baryons in the Skyrme model

We calculate the magnetic moments of heavy baryons in the Skyrme model in the limit of infinite heavy quark mass. We show that the Skyrme model yields the same limit as the nonrelativistic quark model when heavy vector mesons are treated properly. The essential role of the magnetic moment coupling terms in the electromagnetic interactions of heavy mesons is discussed.Comment: 10 pages, REVTeX v3.0, no figur

The baryon number two system in the Chiral Soliton Model

We study the interaction between two B = 1 states in a Chiral Soliton Model where baryons are described as non-topological solitons. By using the hedgehog solution for the B = 1 states we construct three possible B = 2 configurations to analyze the role of the relative orientation of the hedgehog quills in the dynamics. The strong dependence of the intersoliton interaction on these relative orientations reveals that studies of dense hadronic matter using this model should take into account their implications.Comment: 4 pages, 2 figures, Proceedings for the Conference Few-Body Systems (APFB2011

The role of the dilaton in dense skyrmion matter

In this note, we report on a remarkable and surprising interplay between the omega meson and the dilaton chi in the structure of a single skyrmion as well as in the phase structure of dense skyrmion matter which may have a potentially important consequence on the properties of compact stars. In our continuing effort to understand hadronic matter at high density, we have developed a unified field theoretic formalism for dense skyrmion matter using a single Lagrangian to describe simultaneously both matter and meson fluctuations and studied in-medium properties of hadrons. The effective theory used is the Skyrme model Lagrangian gauged with the vector mesons rho and omega, implemented with the dilaton field that describes the spontaneously broken scale symmetry of QCD, in a form consistent with the symmetries of QCD and our expectations regarding the high density limit. We analyze the restoration of scale invariance and chiral symmetry as the density of the system increases. In order to preserve the restoration of scale symmetry and chiral symmetry, signalled in our case by the vanishing of the expectation value of the dilaton, and to be consistent with the vector manifestation of hidden local symmetry, a density dependent omega coupling is introduced. We uncover the crucial role played by both the dilaton and the omega meson in the phase structure of dense medium and discover how two different phase transition regimes arise as we dial the dilaton mass