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Y. Brihaye

Publications and source records attributed to Y. Brihaye.

At least 73 records · Page 4Linked to original sources
arXiv2006

Skyrmion and Skyrme-Black holes in de Sitter spacetime

Numerical arguments are presented for the existence of regular and black hole solutions of the Einstein-Skyrme equations with a positive cosmological constant. These classical configurations approach asymptotically the de Sitter spacetime. The main properties of the solutions and the differences with respect to the asymptotically flat ones are discussed. It particular our results suggest that, for a positive cosmological constant, the mass evaluated as timelike infinity in infinite. Special emphasis is set to De Sitter black holes Skyrmions which display two horizons.

hep-th↗
arXiv2006

Euclidean solutions in Einstein-Yang-Mills-dilaton theory

We present arguments for the existence of a new type of solutions of the Euclidean Einstein-Yang-Mills-dilaton theory in $d=4$ dimensions. Possesing nonvanishing nonabelian charges, these nonselfdual configurations have no counterparts on the Lorentzian section. They provide, however, new saddle points in the Euclidean path integral.

gr-qc↗
arXiv2006

Extended Jaynes-Cummings models and (quasi)-exact solvability

The original Jaynes-Cummings model is described by a Hamiltonian which is exactly solvable. Here we extend this model by several types of interactions leading to a nonhermitian operator which doesn't satisfy the physical condition of space-time reflection symmetry (PT symmetry). However the new Hamiltonians are either exactly solvable admitting an entirely real spectrum or quasi exactly solvable with a real algebraic part of their spectrum.

quant-ph↗
arXiv2005

Black strings in (4+1)-dimensional Einstein-Yang-Mills theory

We study two classes of static uniform black string solutions in a (4+1)-dimensional SU(2) Einstein-Yang-Mills model. These configurations possess a regular event horizon and corresponds in a 4-dimensional picture to axially symmetric black hole solutions in an Einstein-Yang-Mills-Higgs-U(1)-dilaton theory. In this approach, one set of solutions possesses a nonzero magnetic charge, while the other solutions represent black holes located in between a monopole-antimonopole pair. A detailed analysis of the solutions' properties is presented, the domain of existence of the black strings being determined. New four dimensional solutions are found by boosting the five dimensional configurations. We also present an argument for the non-existence of finite mass hyperspherically symmetric black holes in SU(2) Einstein-Yang-Mills theory.

hep-th↗
arXiv2005

Quasi exactly solvable quantum lattice solitons

We extend the exactly solvable Hamiltonian describing $f$ quantum oscillators considered recently by J. Dorignac et al. by means of a new interaction which we choose as quasi exactly solvable. The properties of the spectrum of this new Hamiltonian are studied as function of the new coupling constant. This Hamiltonian as well as the original one are also related to adequate Lie structures.

quant-ph↗
arXiv2005

Dirac oscillators and quasi-exactly solvable operators

The Dirac equation is considered in the background of potentials of several types, namely scalar and vector-potentials as well as "Dirac-oscillator" potential or some of its generalisations. We investigate the radial Dirac equation within a quite general spherically symmetric form for these potentials and we analyse some exactly and quasi exactly solvable properties of the underlying matricial linear operators.

quant-ph↗
arXiv2004

Sphaleron-Bisphaleron bifurcations in a custodial-symmetric two-doublets model

The standard electroweak model is extended by means of a second Brout-Englert-Higgs-doublet. The symmetry breaking potential is chosen is such a way that (i) the Lagrangian possesses a custodial symmetry, (ii) a static, spherically symmetric ansatz of the bosonic fields consistently reduces the Euler-Lagrange equations to a set of differential equations. The potential involves, in particular, products of fields of the two doublets, with a coupling constant $λ_3$.Static, finite energy solutions of the classical equations are constructed. The regular, non-trivial solutions having the lowest classical energy can be of two types: sphaleron or bisphaleron, according to the coupling constants. A special emphasis is put to the bifurcation between these two types of solutions which is analyzed in function of the different constants of the model,namely of $λ_3$.

hep-th↗
arXiv2004

Quadratic integrals of motions for the systems of identical particles-quantum case

The quantum dynamical systems of identical particles admitting an additional integral quadratic in momenta are considered. It is found that an appropriate ordering procedure exists which allows to convert the classical integrals into their quantum counterparts. The relation to the separation of variables in Schroedinger equation is discussed.

nlin.SI↗
arXiv2003

Harmonic Map Analysis of SU(N) Gravitating Skyrmions

In this paper the SU(N) Einstein-Skyrme system is considered. We express the chiral field (which is not a simple embedding of the SU(2) one) in terms of harmonic maps. In this way, SU(N) spherical symmetric equations can be obtained easily for any $N$ and the gravitating skyrmion solutions of these equations can be studied. In particular, the SU(3) case is considered in detail and three different types of gravitating skyrmions with topological charge 4, 2 and 0, respectively, are constructed numerically. Note that the configurations with topological charge 0 correspond to mixtures of skyrmions and antiskyrmions.

hep-th↗
arXiv2003

On PT-symmetric extensions of the Calogero and Sutherland models

The original Calogero and Sutherland models describe N quantum particles on the line interacting pairwise through an inverse square and an inverse sinus-square potential. They are well known to be integrable and solvable. Here we extend the Calogero and Sutherland Hamiltonians by means of new interactions which are PT-symmetric but not self adjoint. Some of these new interactions lead to integrable PT-symmetric Hamiltonians; the algebraic properties further reveal that they are solvable as well. We also consider PT-symmetric interactions which lead to a new quasi-exactly solvable deformation of the Calogero and Sutherland Hamiltonians.

hep-th↗
arXiv2002

An extended model for monopole catalysis of nucleon decay

A new model for monopole catalysis of nucleon decay is proposed. Unlike in the earlier one, the only light fields in this model are the photon and Skyrme (pion) field. The model admits the 't Hooft- Polyakov monopole and Skyrmion as classical solutions, while baryon number non-conservation occurs through an anomaly involving an intermediate mass axial vector field resembling W- and Z-bosons. By considering spherically symmetric monopole-Skyrmion configurations, we find that the Skyrmion looses essentially all its mass when interacting with the monopole, which is phenomenologically identical to the monopole catalysis of nucleon decay. Short-distance monopole-Skyrmion physics in this model is interesting too, as there exist almost degenerate metastable monopole-Skyrmion bound states separated by substantial energy barriers. Yet the heights of the latter are much smaller than the physical nucleon mass, so the complete disappearance of the normal undeformed Skyrmion remains perfectly possible in Skyrmion-monopole scattering.

hep-th↗
arXiv2002

Particle-like solutions to higher order curvature Einstein--Yang-Mills systems in d dimensions

We consider the superposition of the first two members of the gravitational hierarchy (Einstein plus first Gauss-Bonnet(GB)) interacting with the superposition of the first two members of the $SO_{(\pm)}(d)$ Yang--Mills hierarchy, in $d$ dimensions. Such systems can occur in the low energy effective action of string theory. Particle-like solutions %for the systems with only an Einstein term, and with only a GB term, in dimensions $d=6,8$ are constructed respectively. Our results reveal qualitatively new properties featuring double-valued solutions with critical behaviour. In this preliminary study, we have restricted ourselves to one-node solutions.

hep-th↗
arXiv2002

The 1-soliton in the SO(3) gauged Skyrme model with mass term

The solitons of the SO(3) gauged Skyrme model with no pion-mass potential were studied in Refs. {nl,jmp}. Here, the effects of the inclusion of this potential are studied. In contrast with the (ungauged) Skyrme model, where the effect of this potential on the solitons is marginal, here it turns out to be decisive, resulting in very different dependence of the energy as a function of the Skyrme coupling constant.

hep-th↗
arXiv2001

Instantons in 4-dimensional gauged O(5) Skyrme models

We consider a family of four-dimensional non-linear sigma models based on an O(5) symmetric group, whose fields take their values on the 4-sphere S4. An SO(4)-subgroup of the model is gauged. The solutions of the model are characterised by two distinct topological charges, the Chern-Pontryagin charge of the gauge field and the degree of the map, i.e. the winding number, of the S4 field. The one dimensional equations arising from the variation of the action density subjected to spherical symmetry are integrated numerically. Several properties of the solutions thus constructed are pointed out. The only solution with unit Chern-Pontryagin charge are the usual BPST instantons with zero S4 winding number, while solutions with unit S4 winding number have zero Chern-Pontryagin charge.

hep-th↗
arXiv2001

Gravitating monopoles in SU(3) gauge theory

We consider the Einstein-Yang-Mills-Higgs equations for an SU(3) gauge group in a spherically symmetric ansatz. Several properties of the gravitating monopole solutions are obtained an compared with their SU(2) counterpart.

hep-th↗
arXiv2001

A simplified model for monopole catalysis of nucleon decay

We present a simple model where a nucleon is treated as the Skyrmion, both monopole and Skyrmion are smooth solutions of the classical field equations,the baryon number non-conservation is explicitly built in and is due to the classical analogue of the triangle anomaly, and there is no necessity to consider leptons. We show by numerical analysis that there are no static classical solutions with non-zero baryon number on top of the monopole, i.e., that the monopole catalysis of Skyrmion decay indeed proceeds classically.

hep-ph↗