79 research outputs found
Spectral action, Weyl anomaly and the Higgs-Dilaton potential
We show how the bosonic spectral action emerges from the fermionic action by
the renormalization group flow in the presence of a dilaton and the Weyl
anomaly. The induced action comes out to be basically the Chamseddine-Connes
spectral action introduced in the context of noncommutative geometry. The
entire spectral action describes gauge and Higgs fields coupled with gravity.
We then consider the effective potential and show, that it has the desired
features of a broken and an unbroken phase, with the roll down.Comment: 23 pages, 4 figure
Weinberg like sum rules revisited
The generalized Weinberg sum rules containing the difference of isovector
vector and axial-vector spectral functions saturated by both finite and
infinite number of narrow resonances are considered. We summarize the status of
these sum rules and analyze their overall agreement with phenomenological
Lagrangians, low-energy relations, parity doubling, hadron string models, and
experimental data.Comment: 31 pages, noticed misprints are corrected, references are added, and
other minor corrections are mad
On the construction of non-Hermitian Hamiltonians with all-real spectra through supersymmetric algorithms
The energy spectra of two different quantum systems are paired through
supersymmetric algorithms. One of the systems is Hermitian and the other is
characterized by a complex-valued potential, both of them with only real
eigenvalues in their spectrum. The superpotential that links these systems is
complex-valued, parameterized by the solutions of the Ermakov equation, and may
be expressed either in nonlinear form or as the logarithmic derivative of a
properly chosen complex-valued function. The non-Hermitian systems can be
constructed to be either parity-time-symmetric or non-parity-time-symmetric.Comment: 9 pages, 2 figures (affiliation institution corrected
Exactly solvable Wadati potentials in the PT-symmetric Gross-Pitaevskii equation
This note examines Gross-Pitaevskii equations with PT-symmetric potentials of
the Wadati type: . We formulate a recipe for the construction of
Wadati potentials supporting exact localised solutions. The general procedure
is exemplified by equations with attractive and repulsive cubic nonlinearity
bearing a variety of bright and dark solitons.Comment: To appear in Proceedings of the 15 Conference on Pseudo-Hermitian
Hamiltonians in Quantum Physics, May 18-23 2015, Palermo, Italy (Springer
Proceedings in Physics, 2016
Hadronic Contributions to the Muon Anomaly in the Constituent Chiral Quark Model
The hadronic contributions to the anomalous magnetic moment of the muon which
are relevant for the confrontation between theory and experiment at the present
level of accuracy, are evaluated within the same framework: the constituent
chiral quark model. This includes the contributions from the dominant hadronic
vacuum polarization as well as from the next--to--leading order hadronic vacuum
polarization, the contributions from the hadronic light-by-light scattering,
and the contributions from the electroweak hadronic vertex.
They are all evaluated as a function of only one free parameter: the
constituent quark mass. We also comment on the comparison between our results
and other phenomenological evaluations.Comment: Several misprints corrected and a clarifying sentence added. Three
figures superposed and two references added. Version to appear in JHE
Nonlinear Supersymmetry as a Hidden Symmetry
Ver abstrac
Holographic Hadrons in a Confining Finite Density Medium
We study a sector of the hadron spectrum in the presence of finite baryon
density. We use a non-supersymmetric gravity dual to a confining guage theory
which exhibits a running dilaton. The interaction of mesons with the finite
density medium is encoded in the dual theory by a force balancing between
flavor D7-branes and a baryon vertex provided by a wrapped D5-brane. When the
current quark mass m_q is sufficiently large, the meson mass reduces,
exhibiting an interesting spectral flow as we increase the baryon density while
it has a more complicated behaviour for very small m_q.Comment: 34 pages, 20 figures, errors for some figures are fixe
Construction of non-PT-symmetric complex potentials with all-real spectra
We review recent work on the generalization of PT symmetry. We show that, in
addition to PT-symmetric complex potentials, there are also large classes of
non-PT-symmetric complex potentials which also feature all-real spectra. In
addition, some classes of these non-PT-symmetric potentials allow phase
transitions which do or do not go through exceptional points. These
non-PT-symmetric potentials are constructed by a variety of methods, such as
the symmetry and supersymmetry methods and the soliton theory. A generalization
of PT symmetry in multi-dimensions is also reviewed.Comment: 22 pages, 6 figure
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