14 research outputs found
Scattering of spin-polarized electron in an Aharonov--Bohm potential
The scattering of spin-polarized electrons in an Aharonov--Bohm vector
potential is considered. We solve the Pauli equation in 3+1 dimensions taking
into account explicitly the interaction between the three-dimensional spin
magnetic moment of electron and magnetic field. Expressions for the scattering
amplitude and the cross section are obtained for spin-polarized electron
scattered off a flux tube of small radius. It is also shown that bound electron
states cannot occur in this quantum system. The scattering problem for the
model of a flux tube of zero radius in the Born approximation is briefly
discussed.Comment: 11 pages, no figures. Minor typos correcte
Planar Dirac Electron in Coulomb and Magnetic Fields
The Dirac equation for an electron in two spatial dimensions in the Coulomb
and homogeneous magnetic fields is discussed. For weak magnetic fields, the
approximate energy values are obtained by semiclassical method. In the case
with strong magnetic fields, we present the exact recursion relations that
determine the coefficients of the series expansion of wave functions, the
possible energies and the magnetic fields. It is found that analytic solutions
are possible for a denumerably infinite set of magnetic field strengths. This
system thus furnishes an example of the so-called quasi-exactly solvable
models. A distinctive feature in the Dirac case is that, depending on the
strength of the Coulomb field, not all total angular momentum quantum number
allow exact solutions with wavefunctions in reasonable polynomial forms.
Solutions in the nonrelativistic limit with both attractive and repulsive
Coulomb fields are briefly discussed by means of the method of factorization.Comment: 18 pages, RevTex, no figure
Magnetic Oscillations in Dense Cold Quark Matter with Four-Fermion Interactions
The phase structures of Nambu-Jona-Lasinio models with one or two flavours
have been investigated at non-zero values of and , where is an
external magnetic field and is the chemical potential. In the phase
portraits of both models there arise infinitely many massless chirally
symmetric phases, as well as massive ones with spontaneously broken chiral
invariance, reflecting the existence of infinitely many Landau levels. Phase
transitions of first and second orders and a lot of tricritical points have
been shown to exist in phase diagrams. In the massless case, such a phase
structure leads unavoidably to the standard van Alphen-de Haas magnetic
oscillations of some thermodynamical quantities, including magnetization,
pressure and particle density. In the massive case we have found an oscillating
behaviour not only for thermodynamical quantities, but also for a dynamical
quantity as the quark mass. Besides, in this case we have non-standard, i.e.
non-periodic, magnetic oscillations, since the frequency of oscillations is an
-dependent quantity.Comment: latex, 29 pages, 8 figure
Magnetism in Dense Quark Matter
We review the mechanisms via which an external magnetic field can affect the
ground state of cold and dense quark matter. In the absence of a magnetic
field, at asymptotically high densities, cold quark matter is in the
Color-Flavor-Locked (CFL) phase of color superconductivity characterized by
three scales: the superconducting gap, the gluon Meissner mass, and the
baryonic chemical potential. When an applied magnetic field becomes comparable
with each of these scales, new phases and/or condensates may emerge. They
include the magnetic CFL (MCFL) phase that becomes relevant for fields of the
order of the gap scale; the paramagnetic CFL, important when the field is of
the order of the Meissner mass, and a spin-one condensate associated to the
magnetic moment of the Cooper pairs, significant at fields of the order of the
chemical potential. We discuss the equation of state (EoS) of MCFL matter for a
large range of field values and consider possible applications of the magnetic
effects on dense quark matter to the astrophysics of compact stars.Comment: To appear in Lect. Notes Phys. "Strongly interacting matter in
magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Ye
Pair production of charged vector bosons in supercritical magnetic fields at finite temperatures
[[abstract]]The thermodynamic properties of an ideal gas of charged vector bosons (with mass m and charge e) is studied in a strong external homogeneous magnetic field no greater than the critical value Bcr=m2/e. The thermodynamic potential, after appropriate analytic continuation, is then used in the study of the spontaneous production of charged spin-one boson pairs from vacuum in the presence of a supercritical homogeneous magnetic field at finite temperature[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]US
On a test of the self-polarization effect for electrons in storage rings by means of the compton scattering
Translated from RussianSIGLEDEGerman