共查询到20条相似文献,搜索用时 46 毫秒
1.
《Physics letters. A》1988,134(1):42-46
The influence of fermionic zero modes and fractional charges caused by a topological soliton on the dynamics of the system is considered. 相似文献
2.
A. Yu. Loginov 《Journal of Experimental and Theoretical Physics》2012,114(1):48-60
The SU(2) × U(1) gauge model that is the bosonic sector of the Standard Model of electroweak interactions is considered. The existence
of electrically charged nontopological solitons is shown to be possible in this model. Some properties of a charged nontopological
soliton are investigated. Asymptotic expressions are derived for the soliton radius, energy, and phase frequency in the thin-wall
regime by the method of trial functions. Numerical solutions of the model field equations corresponding to electrically charged
non-topological solitions have been obtained. The dependences of the soliton energy and charge on phase frequency are given
for several model parameters. It follows from the data obtained that there exists a domain of parameters in which a charged
nontopological soliton is stable to the transition to a plane-wave field configuration. 相似文献
3.
The Friedberg–Lee (FL) symmetry is generated by a transformation of a fermionic field q to q+ξz. This symmetry puts very restrictive constraints on allowed terms in a Lagrangian. Applying this symmetry to N fermionic fields, we find that the number of independent fields is reduced to N−1 if the fields have gauge interaction or the transformation is a local one. Using this property, we find that a seesaw model originally with three generations of left- and right-handed neutrinos, with the left-handed neutrinos unaffected but the right-handed neutrinos transformed under the local FL translation, is reduced to an effective theory of minimal seesaw which has only two right-handed neutrinos. The symmetry predicts that one of the light neutrino masses must be zero. 相似文献
4.
LIU Yu-Xiao ZHANG Li-Jie DUAN Yi-Shi 《理论物理通讯》2008,49(6):1577-1579
In this letter we study fermionic zero modes in gauge and gravity backgrounds taking a two-dimensional compact manifold S2 as extra dimensions. The result is that there exist massless Dirac fermions which have normalizable zero modes under quite general assumptions about these backgrounds on the bulk. Several special cases of gauge background on the sphere axe discussed and some simple fermionic zero modes are obtained. 相似文献
5.
The purpose of this paper is to investigate an influence of a space-time topology on the formation of fermionic condensate 〈φφ〉 in the model with four-fermion interaction (φφ)2. The value for the space-time with topology of R1 × R1 × S1 is found. Moreover a relation of the value of fermionic condensate to a periodic length is studied. In this connection the possibility of a relation of the topologic deposits to structure of hadrons is discussed. 相似文献
6.
B. Mawlong 《Pramana》2007,69(4):521-531
The charmless nonleptonic decay modes B → f
0
K(π) involving a scalar and a pseudoscalar meson in the final state are studied. The scalar meson f
0 is considered as a q̄q state, as favored by some recent studies. Using the generalized factorization approach, the branching ratios and CP violation
parameters are computed for these modes. The form factors are calculated using the results from relativistic light front quark
model and the ISGW2 model. It is found that the direct CP violation parameters in these modes are small. However, the obtained
branching ratios are not in agreement with the experimental data. Therefore, these modes may be considered as possible probes
for new physics.
相似文献
7.
T. Verkholyak J. Strečka M. Jaščur J. Richter 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,80(4):433-444
The Jordan-Wigner transformation is applied to study magnetic properties of
the quantum spin-
\frac12\frac{1}{2}
XX model on the diamond chain. Generally,
the Hamiltonian of this quantum spin system can be represented in terms of
spinless fermions in the presence of a gauge field and different gauge-invariant
ways of assigning the spin-fermion transformation are considered.
Additionally, we analyze
general properties of a free-fermion chain, where all gauge terms are neglected
and discuss their relevance for the quantum spin system. A consideration of interaction
terms in the fermionic Hamiltonian rests upon the Hartree-Fock procedure after
fixing the appropriate gauge. Finally, we discuss the magnetic properties
of this quantum spin model at zero as well as non-zero temperatures and analyze
the validity of the approximation used through a comparison with the results
of the exact diagonalization method for finite (up to 36 spins) chains.
Besides the m = 1/3 plateau the most prominent feature of the
magnetization curve is a jump at intermediate field present for certain
values of the frustrating vertical bond. 相似文献
8.
We study soliton solutions in supersymmetric scalar field theory with a class of potentials. We study both bosonic and fermionic zero-modes around the soliton solution. We study two possible couplings of gauge fields to these models. While the Born–Infeld like coupling has one normalizable mode (the zero mode), the other kind of coupling has no normalizable modes. We show that quantum mechanical problem which determines the spectrum of fluctuation modes of the scalar, fermion and the gauge field is identical. We also show that only the lowest lying mode, i.e., the zero mode, is normalizable and the rest of the spectrum is continuous. 相似文献
9.
F. Zimmerschied 《Fortschritte der Physik》1996,44(8):707-731
The Lagrangian field-antifield formalism of Batalin and Vilkovisky (BV) is used to investigate the application of the collective coordinate method to soliton quantisation. In field theories with soliton solutions, the Gaussian fluctuation operator has zero modes due to the breakdown of global symmetries of the Lagrangian in the soliton solutions. It is shown how Noether identities and local symmetries of the Lagrangian arise when collective coordinates are introduced in order to avoid divergences related to these zero modes. This transformation to collective and fluctuation degrees of freedom is interpreted as a canonical transformation in the symplectic field-antifield space which induces a time-local gauge symmetry. Separating the corresponding Lagrangian path integral of the BV scheme in lowest order into harmonic quantum fluctuations and a free motion of the collective coordinate with the classical mass of the soliton, we show how the BV approach clarifies the relation between zero modes, collective coordinates, gauge invariance and the center-of-mass motion of classical solutions in quantum fields. Finally, we apply the procedure to the reduced nonlinear O(3) σ-model. 相似文献
10.
M. Ramzan 《Physica A》2013
Non-Markovian dynamics of correlations of fermionic systems is investigated beyond the single-mode approximations in a non-inertial frame. Two well known correlation measures, quantum discord and geometric quantum discord, are analyzed for the fermionic states influenced by the non-Markovian noise. Persistence of discord is seen for longer times depending upon the level of mixedness of the fermionic system. The dynamics of the fermionic systems heavily depends upon the degree of white noise. It is shown that fermionic systems remain dependent upon the choice of Unruh modes (qR) beyond the single-mode approximations under non-Markovian noise. Quantum discord is found to be more robust as compared to the geometric quantum discord. Furthermore, the non-Markovian effects are more stronger than the acceleration of Bob, the accelerated partner. 相似文献
11.
We investigate the stochastic properties of the resistanceR and its logarithm lnR for a one-dimensional disordered conductor of finite length and at zero temperature. In the model which we consider, the non-interacting electrons are scattered by a Gaussian random potential of vanishing correlation length. It is shown that for long samples, lnR is distributed according to a Gaussian law and the parameters of this distribution are calculated explicitly. For weak disorder potentials, we recover known relations between R>, ln<R>, and ln<R
–1>, whereas for strong disorder new results are derived. 相似文献
12.
Fermions localized within vortex cores are considered for the simplest most symmetric vortices in the superfluid phases of 3He. Axisymmetric vortices in the A, A1 and planar phases contain the fermionic condensate with a completely flat band and zero energy. The o-vortex in the B-phase contains 1D Fermi liquids, formed by fermions occupying the branches which cross the zero level. The number of such Fermi liquids increases with increasing external magnetic field. The fermionic spectrum in this vortex is described by the “orbital” and spin momenta interacting with the effective internal magnetic field produced by the vortex and with the external field. Most of the information is obtained using the vortex symmetry which determines symmetry properties of the fermionic spectrum. 相似文献
13.
H. -J. Mikeska B. Vaz da costa H. C. Fogedby 《Zeitschrift für Physik B Condensed Matter》1989,77(1):119-127
The effect of quantum fluctuations on solitons in the easy-plane ferromagnetic chain is considered within the semiclassical approximation. In accordance with the low temperature ideal gas picture we treat the solitons as a Boltzmann gas and impose quantisation on the spin wave spectrum. We present a method which allows to calculate quantum corrections in a systematic perturbation expansion in 1/S, whereS is the spin length. We use this method to obtain the soliton energy to second order at zero temperature. Our results indicate that the semiclassical approach reasonably describes quantum effects on soliton properties. 相似文献
14.
The inverse scattering transform (IST) with nonzero boundary conditions at infinity is developed for a class of 2 × 2 matrix nonlinear Schrödinger-type systems whose reductions include two equations that model certain hyperfine spin F = 1 spinor Bose-Einstein condensates, and two novel equations that were recently shown to be integrable, and that have applications in nonlinear optics and four-component fermionic condensates. In our formulation, both the direct and the inverse problems are posed in terms of a suitable uniformization variable which allows us to develop the IST on the standard complex plane instead of a two-sheeted Riemann surface or the cut plane with discontinuities along the cuts. Analyticity, symmetries and asymptotics of the scattering eigenfunctions and scattering data are derived, and properties of the discrete spectrum are analyzed in detail. In addition, the general behavior of the soliton solutions for all four reductions is discussed, and some novel soliton solutions are presented. 相似文献
15.
The effects of interchain coupling have been studied on the localized vibrational modes around a soliton in doped and photoexcited samples of trans-(CH)x by using an extension of the SSH model in which two neighboring chains modeled individually by SSH Hamiltonian and coupled by an interchain electronic transfer term are considered. The electronic pinning is also included within this model. The localized modes obtained in the SSH model are split and their frequencies are shifted after turning on the interchain coupling. Furthermore, our result can account for the three strong infrared lines at 900, 1260 and 1370 cm?1 along with a weaker peak at 1150 cm? r in the optical absorption spectra of lightly doped samples. 相似文献
16.
Recently the Navier-Stokes equations have been derived from the duality with the black branes in 5AdS. The zero modes of black branes are reinterpreted as dynamical degrees of freedom of a conformal fluid on the boundary of 5AdS. Here, we derive the corrections to the Navier-Stokes equations due to fermionic zero modes of the black branes. We study only the contributions due to bilinears in the fermionic zero modes in the first order of the parameter expansion. The need of a superextension of the fluid dynamics is a consequence of the full AdS/CFT correspondence and yet to be investigated. 相似文献
17.
P. S. Lomdahl 《Journal of statistical physics》1985,39(5-6):551-561
The dynamics of the Josephson tunnel junction is approximately described by a perturbed sine-Gordon equation. The Josephson tunnel junction is thus a convenient experimental solid state device for the study of solitons and solitonlike phenomena. The physical manifestation of the soliton is a propagating magnetic flux quantum (
0=h/2e=2.064×10–15 V sec). Basic properties of the soliton and its relation to observable experimental quantities (zero field steps, microwave radiation, etc.) are reviewed. Recent direct measurements of the actual soliton profile are also mentioned. 相似文献
18.
We study Kaluza-Klein spectrum of type IIB string theory compactified on AdS5×Tnn′ in the context of AdS/CFT correspondence. We examine some of the modes of the complexified 2 form potential as an example and show that for the states at the bottom of the Kaluza-Klein tower the corresponding d=4 boundary field operators have rational conformal dimensions. The masses of some of the fermionic modes in the bottom of each tower as functions of the R charge in the boundary conformal theory are also rational. Furthermore the modes in the bottom of the towers originating from q forms on T11 can be put in correspondence with the BRS cohomology classes of the c=1 non critical string theory with ghost number q. 相似文献
19.
The configurational behaviour and thermodynamic properties of a dilute gas of rigid rod-like molecules in the vicinity of a macroscopic planar adsorption surface are investigated using statistical mechanics. The interaction energy between the surface and a rod-like molecule is determined as a function of both its molecular centre of mass separation R and its orientation relative to the surface. In calculating this interaction energy, each rod segment and molecule comprising the surface is assumed to interact through a Lennard-Jones pair potential. The average molecular order parameter is then determined as a function of R. We find that an isolated rod-like molecule tends to align nearly parallel to the surface for small separations. However, as R increases the order parameter first passes through a maximum then decays to zero as R -5 for large R. The configurational behaviour of an isolated rod-like molecule located between two parallel adsorption surfaces is also considered briefly. The surface spreading pressure, excess surface energy and entropy are also obtained for a dilute gas of rod-like molecules near a surface. We find that the extent of surface binding increases nearly exponentially with molecular length at constant temperature and surface density, and that the excess surface energy and entropy are essentially proportional to the molecular length. 相似文献
20.
Jos D. Edelstein 《Physics letters. [Part B]》1997,390(1-4)
We study the cosmological constant problem in a three-dimensional N = 2 supergravity theory with gauge groupSU (2)global × U(1)local. The model we consider is known to admit string-like configurations, the so-called semi-local cosmic strings. We show that the stability of these solitonic solutions is provided by supersymmetry through the existence of a lower bound for the energy, even though the manifold of the Higgs vacuum does not contain non-contractible loops. Charged Killing spinors do exist over configurations that saturate the Bogomol'nyi bound, as a consequence of an Aharonov-Bohm-like effect. Nevertheless, there are no physical fermionic zero modes on these backgrounds. The exact vanishing of the cosmological constant does not imply, then, Bose-Fermi degeneracy. This provides a non-trivial example of the recent claim made by Witten on the vanishing of the cosmological constant in three dimensions without unphysical degeneracies. 相似文献