46,453 research outputs found
Acceleration-assisted entanglement harvesting and rangefinding
We study entanglement harvested from a quantum field through local
interaction with Unruh-DeWitt detectors undergoing linear acceleration. The
interactions allow entanglement to be swapped locally from the field to the
detectors. We find an enhancement in the entanglement harvesting by two
detectors with anti-parallel acceleration over those with inertial motion. This
enhancement is characterized by the presence of entanglement between two
detectors that would otherwise maintain a separable state in the absence of
relativistic motion (with the same distance of closest approach in both cases).
We also find that entanglement harvesting is degraded for two detectors
undergoing parallel acceleration in the same way as for two static, comoving
detectors in a de Sitter universe. This degradation is known to be different
from that of two inertial detectors in a thermal bath. We comment on the
physical origin of the harvested entanglement and present three methods for
determining distance between two detectors using properties of the harvested
entanglement. Information about the separation is stored nonlocally in the
joint state of the accelerated detectors after the interaction; a single
detector alone contains none. We also find an example of entanglement sudden
death exhibited in parameter space.Comment: 17 pages, 6 figures. Version 2 updated to address referee comments
and minor correction
Collisions of Deformed Nuclei: A Path to the Far Side of the Superheavy Island
A detailed understanding of complete fusion cross sections in heavy-ion
collisions requires a consideration of the effects of the deformation of the
projectile and target. Our aim here is to show that deformation and orientation
of the colliding nuclei have a very significant effect on the fusion-barrier
height and on the compactness of the touching configuration. To facilitate
discussions of fusion configurations of deformed nuclei, we develop a
classification scheme and introduce a notation convention for these
configurations. We discuss particular deformations and orientations that lead
to compact touching configurations and to fusion-barrier heights that
correspond to fairly low excitation energies of the compound systems. Such
configurations should be the most favorable for producing superheavy elements.
We analyse a few projectile-target combinations whose deformations allow
favorable entrance-channel configurations and whose proton and neutron numbers
lead to compound systems in a part of the superheavy region where alpha
half-lives are calculated to be observable, that is, longer than 1 microsecond.Comment: 15 pages. LaTeX with iopconf.sty style file. Submitted to Nuclear
Physics A. 25 figures not included here. PostScript version with figures
available at http://t2.lanl.gov/pub/publications/publications.html or at
ftp://t2.lanl.gov/pub/publications/cd
Self-testing and repairing computer Patent
Self testing and repairing computer comprising control and diagnostic unit and rollback points for error correctio
Structural patterns in complex networks through spectral analysis
The study of some structural properties of networks is introduced from a graph spectral perspective. First, subgraph centrality of nodes is defined and used to classify essential proteins in a proteomic map. This index is then used to produce a method that allows the identification of superhomogeneous networks. At the same time this method classify non-homogeneous network into three universal classes of structure. We give examples of these classes from networks in different real-world scenarios. Finally, a communicability function is studied and showed as an alternative for defining communities in complex networks. Using this approach a community is unambiguously defined and an algorithm for its identification is proposed and exemplified in a real-world network
Learning from power system data stream: phasor-detective approach
Assuming access to synchronized stream of Phasor Measurement Unit (PMU) data
over a significant portion of a power system interconnect, say controlled by an
Independent System Operator (ISO), what can you extract about past, current and
future state of the system? We have focused on answering this practical
questions pragmatically - empowered with nothing but standard tools of data
analysis, such as PCA, filtering and cross-correlation analysis. Quite
surprisingly we have found that even during the quiet "no significant events"
period this standard set of statistical tools allows the "phasor-detective" to
extract from the data important hidden anomalies, such as problematic control
loops at loads and wind farms, and mildly malfunctioning assets, such as
transformers and generators. We also discuss and sketch future challenges a
mature phasor-detective can possibly tackle by adding machine learning and
physics modeling sophistication to the basic approach
Correcting low-frequency noise with continuous measurement
Low-frequency noise presents a serious source of decoherence in solid-state
qubits. When combined with a continuous weak measurement of the eigenstates,
the low-frequency noise induces a second-order relaxation between the qubit
states. Here we show that the relaxation provides a unique approach to
calibrate the low-frequency noise in the time-domain. By encoding one qubit
with two physical qubits that are alternatively calibrated, quantum logic gates
with high fidelity can be performed.Comment: 10 pages, 3 figures, submitte
- …