135 research outputs found
Electrodynamics of balanced charges
In this work we modify the wave-corpuscle mechanics for elementary charges
introduced by us recently. This modification is designed to better describe
electromagnetic (EM) phenomena at atomic scales. It includes a modification of
the concept of the classical EM field and a new model for the elementary charge
which we call a balanced charge (b-charge). A b-charge does not interact with
itself electromagnetically, and every b-charge possesses its own elementary EM
field. The EM energy is naturally partitioned as the interaction energy between
pairs of different b-charges. We construct EM theory of b-charges (BEM) based
on a relativistic Lagrangian with the following properties: (i) b-charges
interact only through their elementary EM potentials and fields; (ii) the field
equations for the elementary EM fields are exactly the Maxwell equations with
proper currents; (iii) a free charge moves uniformly preserving up to the
Lorentz contraction its shape; (iv) the Newton equations with the Lorentz
forces hold approximately when charges are well separated and move with
non-relativistic velocities. The BEM theory can be characterized as
neoclassical one which covers the macroscopic as well as the atomic spatial
scales, it describes EM phenomena at atomic scale differently than the
classical EM theory. It yields in macroscopic regimes the Newton equations with
Lorentz forces for centers of well separated charges moving with
nonrelativistic velocities. Applied to atomic scales it yields a hydrogen atom
model with a frequency spectrum matching the same for the Schrodinger model
with any desired accuracy.Comment: Manuscript was edited to improve the exposition and to remove noticed
typo
Gauge Theories with Cayley-Klein and Gauge Groups
Gauge theories with the orthogonal Cayley-Klein gauge groups and
are regarded. For nilpotent values of the contraction
parameters these groups are isomorphic to the non-semisimple Euclid,
Newton, Galilei groups and corresponding matter spaces are fiber spaces with
degenerate metrics. It is shown that the contracted gauge field theories
describe the same set of fields and particle mass as gauge
theories, if Lagrangians in the base and in the fibers all are taken into
account. Such theories based on non-semisimple contracted group provide more
simple field interactions as compared with the initial ones.Comment: 14 pages, 5 figure
Quantized Roentgen Effect in Bose-Einstein Condensates
A classical dielectric moving in a charged capacitor can create a magnetic
field (Roentgen effect). A quantum dielectric, however, will not produce a
magnetization, except at vortices. The magnetic field outside the quantum
dielectric appears as the field of quantized monopoles
Theory of quantum radiation observed as sonoluminescence
Sonoluminescence is explained in terms of quantum radiation by moving
interfaces between media of different polarizability. In a stationary
dielectric the zero-point fluctuations of the electromagnetic field excite
virtual two-photon states which become real under perturbation due to motion of
the dielectric. The sonoluminescent bubble is modelled as an optically empty
cavity in a homogeneous dielectric. The problem of the photon emission by a
cavity of time-dependent radius is handled in a Hamiltonian formalism which is
dealt with perturbatively up to first order in the velocity of the bubble
surface over the speed of light. A parameter-dependence of the zero-order
Hamiltonian in addition to the first-order perturbation calls for a new
perturbative method combining standard perturbation theory with an adiabatic
approximation. In this way the transition amplitude from the vacuum into a
two-photon state is obtained, and expressions for the single-photon spectrum
and the total energy radiated during one flash are given both in full and in
the short-wavelengths approximation when the bubble is larger than the
wavelengths of the emitted light. It is shown analytically that the spectral
density has the same frequency-dependence as black-body radiation; this is
purely an effect of correlated quantum fluctuations at zero temperature. The
present theory clarifies a number of hitherto unsolved problems and suggests
explanations for several more. Possible experiments that discriminate this from
other theories of sonoluminescence are proposed.Comment: Latex file, 28 pages, postscript file with 3 figs. attache
General Relativity in Electrical Engineering
In electrical engineering metamaterials have been developed that offer
unprecedented control over electromagnetic fields. Here we show that general
relativity lends the theoretical tools for designing devices made of such
versatile materials. Given a desired device function, the theory describes the
electromagnetic properties that turn this function into fact. We consider media
that facilitate space-time transformations and include negative refraction. Our
theory unifies the concepts operating behind the scenes of perfect invisibility
devices, perfect lenses, the optical Aharonov-Bohm effect and electromagnetic
analogs of the event horizon, and may lead to further applications
Optics of Nonuniformly Moving Media
A moving dielectric appears to light as an effective gravitational field. At
low flow velocities the dielectric acts on light in the same way as a magnetic
field acts on a charged matter wave. We develop in detail the geometrical
optics of moving dispersionless media. We derive a Hamiltonian and a Lagrangian
to describe ray propagation. We elucidate how the gravitational and the
magnetic model of light propagation are related to each other. Finally, we
study light propagation around a vortex flow. The vortex shows an optical
Aharonov--Bohm effect at large distances from the core, and, at shorter ranges,
the vortex may resemble an optical black hole.Comment: Physical Review A (submitted
Shape-induced force fields in optical trapping
Advances in optical tweezers, coupled with the proliferation of two-photon polymerization systems, mean that it is now becoming routine to fabricate and trap non-spherical particles. The shaping of both light beams and particles allows fine control over the flow of momentum from the optical to mechanical regimes. However, understanding and predicting the behaviour of such systems is highly complex in comparison with the traditional optically trapped microsphere. In this Article, we present a conceptually new and simple approach based on the nature of the optical force density. We illustrate the method through the design and fabrication of a shaped particle capable of acting as a passive force clamp, and we demonstrate its use as an optically trapped probe for imaging surface topography. Further applications of the design rules highlighted here may lead to new sensors for probing biomolecule mechanics, as well as to the development of optically actuated micromachines
Plasmonic nanoparticle monomers and dimers: From nano-antennas to chiral metamaterials
We review the basic physics behind light interaction with plasmonic
nanoparticles. The theoretical foundations of light scattering on one metallic
particle (a plasmonic monomer) and two interacting particles (a plasmonic
dimer) are systematically investigated. Expressions for effective particle
susceptibility (polarizability) are derived, and applications of these results
to plasmonic nanoantennas are outlined. In the long-wavelength limit, the
effective macroscopic parameters of an array of plasmonic dimers are
calculated. These parameters are attributable to an effective medium
corresponding to a dilute arrangement of nanoparticles, i.e., a metamaterial
where plasmonic monomers or dimers have the function of "meta-atoms". It is
shown that planar dimers consisting of rod-like particles generally possess
elliptical dichroism and function as atoms for planar chiral metamaterials. The
fabricational simplicity of the proposed rod-dimer geometry can be used in the
design of more cost-effective chiral metamaterials in the optical domain.Comment: submitted to Appl. Phys.
A significant proportion of classic Hodgkin lymphoma recurrences represents clonally unrelated second primary lymphoma
Despite high cure rates in classic Hodgkin lymphoma (cHL), relapses are observed. Whether relapsed cHL represents second primary lymphoma or an underlying T-cell lymphoma (TCL) mimicking cHL is under-investigated. To analyze the nature of cHL recurrences, in-depth clonality testing of immunoglobulin (IG) and T-cell receptor (TR) rearrangements was performed in paired cHL diagnosis and recurrences of 60 patients, supported by targeted mutation analysis of lymphoma-associated genes. Clonal IG rearrangements were detected by next-generation sequencing (NGS) in 69/120 (58%) diagnosis and recurrence samples. The clonal relationship could be established in 34 cases, identifying clonally related relapsed cHL in 24/34 patients (71%). Clonally unrelated cHL was observed in 10/34 patients (29%) as determined by IG-NGS clonality assessment, and confirmed by the identification of predominantly mutually exclusive gene mutations in the paired cHL samples. In recurrences of >2 years, ~60% of cHL patients for which the clonal relationship could be established showed a second primary cHL. Clonal TR gene rearrangements were identified in 14/125 samples (11%), and TCL-associated gene mutations were detected in 7/14 samples. Retrospective pathology review with integration of the molecular findings were consistent with an underlying TCL in 5 patients aged >50 years. This study shows that cHL recurrences, especially after 2 years, sometimes represent a new primary cHL or TCL mimicking cHL, as uncovered by NGS-based IG/TR clonality testing and gene mutation analysis. Given the significant therapeutic consequences, molecular testing of a presumed relapse in cHL is crucial for subsequent appropriate treatment strategies adapted to the specific lymphoma presentation.</p
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