207 research outputs found
Photon mass and quantum effects of the Aharonov-Bohm type
The magnetic field due to the photon rest mass modifies the standard
results of the Aharonov-Bohm effect for electrons, and of other recent quantum
effects. For the effect involving a coherent superposition of beams of
particles with opposite electromagnetic properties, by means of a table-top
experiment, the limit is achievable, improving by 6 orders
of magnitude that derived by Boulware and Deser for the Aharonov-Bohm effect.Comment: 5 page
Relativistic Aharonov-Casher Phase in Spin One
The Aharonov-Casher (AC) phase is calculated in relativistic wave equations
of spin one. The AC phase has previously been calculated from the Dirac-Pauli
equation using a gauge-like technique \cite{MK1,MK2}. In the spin-one case, we
use Kemmer theory (a Dirac-like particle theory) to calculate the phase in a
similar manner. However the vector formalism, the Proca theory, is more widely
known and used. In the presence of an electromagnetic field, the two theories
are `equivalent' and may be transformed into one another. We adapt these
transformations to show that the Kemmer theory results apply to the Proca
theory. Then we calculate the Aharonov-Casher phase for spin-one particles
directly in the Proca formalism.Comment: 12 page
Modular Acquisition and Stimulation System for Timestamp-Driven Neuroscience Experiments
Dedicated systems are fundamental for neuroscience experimental protocols
that require timing determinism and synchronous stimuli generation. We
developed a data acquisition and stimuli generator system for neuroscience
research, optimized for recording timestamps from up to 6 spiking neurons and
entirely specified in a high-level Hardware Description Language (HDL). Despite
the logic complexity penalty of synthesizing from such a language, it was
possible to implement our design in a low-cost small reconfigurable device.
Under a modular framework, we explored two different memory arbitration schemes
for our system, evaluating both their logic element usage and resilience to
input activity bursts. One of them was designed with a decoupled and latency
insensitive approach, allowing for easier code reuse, while the other adopted a
centralized scheme, constructed specifically for our application. The usage of
a high-level HDL allowed straightforward and stepwise code modifications to
transform one architecture into the other. The achieved modularity is very
useful for rapidly prototyping novel electronic instrumentation systems
tailored to scientific research.Comment: Preprint submitted to ARC 2015. Extended: 16 pages, 10 figures. The
final publication is available at link.springer.co
Bound states in the dynamics of a dipole in the presence of a conical defect
In this work we investigate the quantum dynamics of an electric dipole in a
-dimensional conical spacetime. For specific conditions, the
Schr\"odinger equation is solved and bound states are found with the energy
spectrum and eigenfunctions determined. We find that the bound states spectrum
extends from minus infinity to zero with a point of accumulation at zero. This
unphysical result is fixed when a finite radius for the defect is introduced.Comment: 4 page
Quantum phases of electric dipole ensembles in atom chips
We present how a phase factor is generated when an electric dipole moves
along a closed trajectory inside a magnetic field gradient. The similarity of
this situation with charged particles in a magnetic field can be employed to
simulate condensed matter models, such as the quantum Hall effect and chiral
spin Hamiltonians, with ultra cold atoms integrated on atom chips. To
illustrate this we consider a triangular configuration of a two dimensional
optical lattice, where the chiral spin Hamiltonian can be generated between any three
neighbours on a lattice yielding an experimentally implementable chiral ground
state.Comment: 4 pages, 2 figures, REVTEX. Title slightly changed and conclusions
extende
Classical and Quantum Interaction of the Dipole
A unified and fully relativistic treatment of the interaction of the electric
and magnetic dipole moments of a particle with the electromagnetic field is
given. New forces on the particle due to the combined effect of electric and
magnetic dipoles are obtained. Four new experiments are proposed, three of
which would observe topological phase shifts.Comment: 10 pages, Latex/Revtex. Some minor errors have been correcte
The Micro Black Hole Cellular Battery: The Ultimate Limits of Battery Energy Density
With the clean energy revolution, many methods of energy production, such as solar and wind power, are quite unstable because of weather variability. However, energy consumption remains relatively stable. Therefore, efficient energy storage could be crucial for the future. In this context, we will explore the theoretical limits of battery efficiency in terms of energy density. Surprisingly, although quite speculative, a potential solution might involve a cellular battery composed of micro black holes. In fact, let us suppose hypothetically that advanced future technology can handle the formation of black holes. Then, according to the extremal solution of the Reissner–Nordström metric from general relativity, such a battery could be stable and would not collapse into a larger black hole because the electromagnetic repulsion would precisely offset the force of gravity. Additionally, although it is generally assumed that nothing can escape from a black hole, a micro black hole could possibly annihilate another micro black hole, resulting in the release of an enormous amount of clean energy. For example, a battery weighing just one kilogram could provide approximately 470 million times the energy of the most efficient 200-kilogram lithium battery at the time of writing. While achieving such a level of technological advancement is certainly not imminent, it is not inconceivable that battery technology development could follow a trajectory similar to that of computer technology. Just as breakthroughs in physics and computer engineering have led to exponential growth in computer efficiency in the last 50 years, it is possible that battery efficiency could double or even quadruple every few years following different types of breakthroughs. Nonetheless, the theoretical concept of a micro black hole battery appears to align with current predictions of fundamental physics regarding the ultimate physical limits on energy density storage. This strongly indicates we are at the very early stage of battery technology, not even close to the end.publishedVersio
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