Modern Physics Letters A

This is an extended version of the note taken by the first author (W.-G.P.) on a lecture given by the second author (M.R.) as a first part of the series on "Hadronic Matter Under Extreme Conditions," the principal theme of the WCU-Hanyang Program. It covers the attempts to go in a framework anchored on effective field theory of QCD from zero density to the nuclear matter density and slightly beyond, with the ultimate goal of arriving at the density relevant to compact stars, including chiral phase transition and quark matter. The focus is on the conceptual aspects rather than detailed "fitting" of the data on the kinds of physics that are being addressed to in radioactive-ion-beam machines in operation as well as in project (such as "KoRIA" in Korea) and will be explored at such forthcoming accelerators as FAIR/GSI. The approach presented here is basically different from the standard ones found in the literature in that the notion of hidden local symmetry — which underlies the chiral symmetry of the strong interactions — and its generalization to dual gravity description involving infinite tower of hidden gauge fields are closely relied on.

In this paper, we propose an effective model scheme that describes the electroweak symmetry breaking sector by means of composite Higgs-like scalars, following the ideas of Minimal Walking Technicolor (MWT). We argue that, because of the general failure of Extended Technicolor (ETC) to explain the mass of the top quark, it is necessary to introduce two composite Higgs bosons: one of them originated by a MWT–ETC sector and the other produced by a Topcolor sector. We focus on the phenomenological differences between the light composite Higgs present in our model and the fundamental Higgs boson predicted by the Standard Model and their production at the LHC. We show that in this scheme the main production channel of the lighter Higgs boson is the associated production with a gauge boson and WW fusion but not the gluon–gluon fusion channel which is substantially suppressed.

In a 5D spacetime with a 3-brane embedded we calculate the second variation of the scalar 4D curvature term on the brane under variations of the 5D metric. It is shown that the second variation of the 4D scalar curvature term in adapted coordinates is expressed only through variations of the components of the 5D metric with 4D indices.

Attempts to go beyond the framework of local quantum field theory include scenarios in which the action of external symmetries on the quantum fields Hilbert space is deformed. We show how the Fock spaces of such theories exhibit a richer structure in their multi-particle sectors. When the deformation scale is proportional to the Planck energy, such new structure leads to the emergence of a "planckian" mode-entanglement, invisible to an observer that cannot probe the Planck scale. To the same observer, certain unitary processes would appear non-unitary. We show how entanglement transfer to the additional degrees of freedom can provide a potential way out of the black hole information paradox.

The new potential model for pionic hydrogen, constructed with the employment of the two-body relativistic equation, is offered. The relativistic equation, based on the extension of the SL(2, C) group to the Sp(4, C) one, describes the effect of the proton spin and anomalous magnetic moment in accordance with the results of the quantum electrodynamics. Within this approach, using the experimental data on the strong energy level shift and width of the 1s state in pionic hydrogen as input, the pion–nucleon scattering lengths have been evaluated to be and

We analyze the stability of a Bose–Einstein condensate in a Lorentz violating scenario, which is characterized by a deformation in the dispersion relation. The incorporation of a Lorentz violation within the bosonic statistics has, as a consequence, the emergence of a pseudo-interaction, the one can be associated to a characteristic scattering length. In addition, we calculate the relevant parameters associated to the stability of such condensate incorporating this pseudo-interaction in the nonlinear term of the Gross–Pitaevskii equation. We show that these parameters must be corrected, as a consequence of the quantum structure of spacetime.

Adopting the gauge-invariant but path-dependent variables formalism, we study the coupling of torsion fields with photons in the presence of an external background electromagnetic. We explicitly show that, in the case of a constant electric field strength expectation value, the static potential remains Coulombic, while in the case of a constant magnetic field strength expectation value a confining potential is obtained. This result displays a marked qualitative departure from the usual coupling of axionlike particles with photons in the presence of an external magnetic field.