589 research outputs found
Quantum motion in superposition of Aharonov-Bohm with some additional electromagnetic fields
The structure of additional electromagnetic fields to the Aharonov-Bohm
field, for which the Schr\"odinger, Klein-Gordon, and Dirac equations can be
solved exactly are described and the corresponding exact solutions are found.
It is demonstrated that aside from the known cases (a constant and uniform
magnetic field that is parallel to the Aharonov-Bohm solenoid, a static
spherically symmetrical electric field, and the field of a magnetic monopole),
there are broad classes of additional fields. Among these new additional fields
we have physically interesting electric fields acting during a finite time, or
localized in a restricted region of space. There are additional time-dependent
uniform and isotropic electric fields that allow exact solutions of the
Schrodinger equation. In the relativistic case there are additional electric
fields propagating along the Aharonov-Bohm solenoid with arbitrary electric
pulse shape
Twisted electron in a strong laser wave
Electrons carrying orbital angular momentum (OAM) have recently been
discovered theoretically and obtained experimentally that opens up
possibilities for using them in high-energy physics. We consider such a twisted
electron moving in external field of a plane electromagnetic wave and study how
this field influences the electron's OAM. Being motivated by the development of
high-power lasers, we focus our attention on a classically strong field regime
for which . It is shown that along with
the well-known "plane-wave" Volkov solution, Dirac equation also has the
"non-plane-wave" solutions, which possess OAM and a spin-orbit coupling, and
generalize the free-electron's Bessel states. Motion of the electron with OAM
in a circularly polarized laser wave reveals a twofold character: the
wave-packet center moves along a classical helical trajectory with some quantum
transverse broadening (due to OAM) existing even for a free electron. Using the
twisted states, we calculate the electron's total angular momentum and predict
its shift in the strong-field regime that is analogous to the well-known shifts
of the electron's momentum and mass (and to a less known shift of its spin) in
intense fields. Since the electron's effective angular momentum is conserved in
a plane wave, as well as in some more general field configurations, we discuss
several possibilities for accelerating non-relativistic twisted electrons by
using the focused and combined electromagnetic fields.Comment: to appear in PR
Holographic fermions at strong translational symmetry breaking: a Bianchi-VII case study
It is presently unknown how strong lattice potentials influence the fermion
spectral function of the holographic strange metals predicted by the AdS/CFT
correspondence. This embodies a crucial test for the application of holography
to condensed matter experiments. We show that for one particular momentum
direction this spectrum can be computed for arbitrary strength of the effective
translational symmetry breaking potential of the so-called Bianchi-VII geometry
employing ordinary differential equations. Deep in the strange metal regime we
find rather small changes to the single-fermion response computed by the
emergent quantum critical IR, even when the potential becomes relevant in the
infra-red. However, in the regime where holographic quasi-particles occur,
defining a Fermi surface in the continuum, they acquire a finite lifetime at
any finite potential strength. At the transition from irrelevancy to relevancy
of the Bianchi potential in the deep infra-red the quasi-particle remnants
disappear completely and the fermion spectrum exhibits a purely relaxational
behaviour.Comment: 30 pages, 10 figure
Aharonov-Bohm Effect in Cyclotron and Synchrotron Radiations
We study the impact of Aharonov-Bohm solenoid on the radiation of a charged
particle moving in a constant uniform magnetic field. With this aim in view,
exact solutions of Klein-Gordon and Dirac equations are found in the
magnetic-solenoid field. Using such solutions, we calculate exactly all the
characteristics of one-photon spontaneous radiation both for spinless and
spinning particle. Considering non-relativistic and relativistic
approximations, we analyze cyclotron and synchrotron radiations in detail.
Radiation peculiarities caused by the presence of the solenoid may be
considered as a manifestation of Aharonov-Bohm effect in the radiation. In
particular, it is shown that new spectral lines appear in the radiation
spectrum. Due to angular distribution peculiarities of the radiation intensity,
these lines can in principle be isolated from basic cyclotron and synchrotron
radiation spectraComment: 38 pages, LaTex fil
Quantum deformation of the angular distributions of synchrotron radiation. Emission of particles in the first excited state
The exact expressions for the characteristics of synchrotron radiation of
charged particles in the first excited state are obtained in analytical form
using quantum theory methods. We performed a detailed analysis of the angular
distribution structure of radiation power and its polarization for particles
with spin 0 and 1/2. It is shown that the exact quantum calculations lead to
results that differ substantially from the predictions of classical theory
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