14,957 research outputs found
Implications of Lorentz covariance for the guidance equation in two-slit quantum interference
It is known that Lorentz covariance fixes uniquely the current and the
associated guidance law in the trajectory interpretation of quantum mechanics
for spin particles. In the non-relativistic domain this implies a guidance law
for the electron which differs by an additional spin-dependent term from that
originally proposed by de Broglie and Bohm. In this paper we explore some of
the implications of the modified guidance law. We bring out a property of
mutual dependence in the particle coordinates that arises in product states,
and show that the quantum potential has scalar and vector components which
implies the particle is subject to a Lorentz-like force. The conditions for the
classical limit and the limit of negligible spin are given, and the empirical
sufficiency of the model is demonstrated. We then present a series of
calculations of the trajectories based on two-dimensional Gaussian wave packets
which illustrate how the additional spin-dependent term plays a significant
role in structuring both the individual trajectories and the ensemble. The
single packet corresponds to quantum inertial motion. The distinct features
encountered when the wavefunction is a product or a superposition are explored,
and the trajectories that model the two-slit experiment are given. The latter
paths exhibit several new characteristics compared with the original de
Broglie-Bohm ones, such as crossing of the axis of symmetry.Comment: 27 pages including 6 pages of figure
Time and Ensemble Averages in Bohmian Mechanics
We show that in the framework of one-dimensional Bohmian Quantum
Mechanics[1], for a particle subject to a potential undergoing a weak adiabatic
change, the time averages of the particle's positions typically differ markedly
from the ensemble averages. We Apply this result to the case where the weak
perturbing potential is the back-action of a measuring device (i.e. a
protective measurement). It is shown that under these conditions, most
trajectories never cross the position measured (as already shown for a
particular example in [3]).Comment: 6 page
Universal error corrections for finite semiconductor resistivity in cross-kelvin resistor test structures
The Cross-Kelvin Resistor test structure is commonly used for the extraction of the specific contact resistance of ohmic contacts. Analysis using this structure are generally based on a two-dimensional model that assumes zero voltage drop in the semiconductor layer in the direction normal to the plane of the contact. This paper uses a three-dimensional (3-D) analysis to show the magnitude of the errors introduced by this assumption, and illustrates the conditions under which a 3-D analysis should be used. This paper presents for the first time 3-D universal error correction curves that account for the vertical voltage drop due to the finite depth of the semiconductor laye
A first experimental test of de Broglie-Bohm theory against standard quantum mechanics
De Broglie - Bohm (dBB) theory is a deterministic theory, built for
reproducing almost all Quantum Mechanics (QM) predictions, where position plays
the role of a hidden variable. It was recently shown that different coincidence
patterns are predicted by QM and dBB when a double slit experiment is realised
under specific conditions and, therefore, an experiment can test the two
theories. In this letter we present the first realisation of such a double slit
experiment by using correlated photons produced in type I Parametric Down
Conversion. Our results confirm QM contradicting dBB predictions
Finite element modeling of misalignment in interconnect vias
Electrical resistance and hence heat generation in semiconductor chips are becoming more significant issues particularily as generations of silicon devices continue to have smaller features. The resistance of interconnect vias is a significant source of heat generation because of the increasing number of these on chips and increases in via resistance due to reduced size. Finite element modeling of voltage drops and current flow through interconnect vias gives information to aid in designing geometry and materials used in forming vias. It can also be used for modeling the thermal distribution in a via and hence the contribution by vias to heating a chip. In this paper we examine the effect of misalignment of the via between the two metal layers M1 and M2 with regard to the interconnect via resistance. The effect of the interface specific contact resistance is examined in particular. Significant misalignment can be tolerated without increasing the via resistance. The heat generation due to electrical current flow in the via materials and interfaces is modelled using the samefinite element mesh and software. The output of the electrical analysis is used as the heat generation input for the therml analysis
Investigating people: a qualitative analysis of the search behaviours of open-source intelligence analysts
The Internet and the World Wide Web have become integral parts of the lives of many modern individuals, enabling almost instantaneous communication, sharing and broadcasting of thoughts, feelings and opinions. Much of this information is publicly facing, and as such, it can be utilised in a multitude of online investigations, ranging from employee vetting and credit checking to counter-terrorism and fraud prevention/detection. However, the search needs and behaviours of these investigators are not well documented in the literature. In order to address this gap, an in-depth qualitative study was carried out in cooperation with a leading investigation company. The research contribution is an initial identification of Open-Source Intelligence investigator search behaviours, the procedures and practices that they undertake, along with an overview of the difficulties and challenges that they encounter as part of their domain. This lays the foundation for future research in to the varied domain of Open-Source Intelligence gathering
Proof Theory and Ordered Groups
Ordering theorems, characterizing when partial orders of a group extend to
total orders, are used to generate hypersequent calculi for varieties of
lattice-ordered groups (l-groups). These calculi are then used to provide new
proofs of theorems arising in the theory of ordered groups. More precisely: an
analytic calculus for abelian l-groups is generated using an ordering theorem
for abelian groups; a calculus is generated for l-groups and new decidability
proofs are obtained for the equational theory of this variety and extending
finite subsets of free groups to right orders; and a calculus for representable
l-groups is generated and a new proof is obtained that free groups are
orderable
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Search for Q: single grains Xe isotope analysis of carbonaceous residue from Yilmia
We analyse Xe in single grains in HF-HCl residue from Yilmia using RELAX mass spectrometer
Cost benefit analysis of space communications technology. Volume 2: Final report
For abstract, see preceding accession
HST/STIS Imaging of the Host Galaxy of GRB980425/SN1998bw
We present HST/STIS observations of ESO 184-G82, the host galaxy of the
gamma-ray burst GRB 980425 associated with the peculiar Type Ic supernova
SN1998bw. ESO 184-G82 is found to be an actively star forming SBc sub-luminous
galaxy. We detect an object consistent with being a point source within the
astrometric uncertainty of 0.018 arcseconds of the position of the supernova.
The object is located inside a star-forming region and is at least one
magnitude brighter than expected for the supernova based on a simple
radioactive decay model. This implies either a significant flattening of the
light curve or a contribution from an underlying star cluster.Comment: 12 pages, 2 figures, AASTeX v5.02 accepted for publication in ApJ
Letter
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