187,495 research outputs found
Pulsar Velocity with Three-Neutrino Oscillations in Non-adiabatic Processes
We have studied the position dependence of neutrino energy on the
Kusenko-Segr\`{e} mechanism as an explanation of the proper motion of pulsars.
The mechanism is also examined in three-generation mixing of neutrinos and in a
non-adiabatic case. The position dependence of neutrino energy requires the
higher value of magnetic field such as Gauss in order
to explain the observed proper motion of pulsars. It is shown that possible
non-adiabatic processes decrease the neutrino momentum asymmetry, whereas an
excess of electron neutrino flux over other flavor neutrino fluxes increases
the neutrino momentum asymmetry. It is also shown that a general treatment with
all three neutrinos does not modify the result of the two generation treatment
if the standard neutrino mass hierarchy is assumed.Comment: 8 pages, REVTEX, no figure
Entropy of the Randall-Sundrum brane world with the generalized uncertainty principle
By introducing the generalized uncertainty principle, we calculate the
entropy of the bulk scalar field on the Randall-Sundrum brane background
without any cutoff. We obtain the entropy of the massive scalar field
proportional to the horizon area. Here, we observe that the mass contribution
to the entropy exists in contrast to all previous results, which is independent
of the mass of the scalar field, of the usual black hole cases with the
generalized uncertainty principle.Comment: 12 pages. The improved version published in Phys. Rev.
Lagrangian approach to local symmetries and self-dual model in gauge invariant formulation
Taking the St\"uckelberg Lagrangian associated with the abelian self-dual
model of P.K. Townsend et al as a starting point, we embed this mixed first-
and second-class system into a pure first-class system by following
systematically the generalized Hamiltonian approach of Batalin, Fradkin and
Tyutin. The resulting Lagrangian possesses an extended gauge invariance and
provides a non-trivial example for a general Lagrangian approach to unravelling
the full set of local symmetries of a Lagrangian.Comment: LaTeX, 15 page
Arterial pulse wave pressure transducer
An arterial pulse wave pressure transducer is introduced. The transducer is comprised of a fluid filled cavity having a flexible membrane disposed over the cavity and adapted to be placed on the skin over an artery. An arterial pulse wave creates pressure pulses in the fluid which are transduced, by a pressure sensitive transistor in direct contact with the fluid, into an electric signal. The electrical signal is representative of the pulse waves and can be recorded so as to monitor changes in the elasticity of the arterial walls
Potential contributions of noncontact atomic force microscopy for the future Casimir force measurements
Surface electric noise, i.e., the non-uniform distribution of charges and
potentials on a surface, poses a great experimental challenge in modern
precision force measurements. Such a challenge is encountered in a number of
different experimental circumstances. The scientists employing atomic force
microscopy (AFM) have long focused their efforts to understand the
surface-related noise issues via variants of AFM techniques, such as Kelvin
probe force microscopy or electric force microscopy. Recently, the physicists
investigating quantum vacuum fluctuation phenomena between two closely-spaced
objects have also begun to collect experimental evidence indicating a presence
of surface effects neglected in their previous analyses. It now appears that
the two seemingly disparate science communities are encountering effects rooted
in the same surface phenomena. In this report, we suggest specific experimental
tasks to be performed in the near future that are crucial not only for
fostering needed collaborations between the two communities, but also for
providing valuable data on the surface effects in order to draw the most
realistic conclusion about the actual contribution of the Casimir force (or van
der Waals force) between a pair of real materials.Comment: The paper appeared in the Proceedings to the 12th International
Conference on Noncontact Atomic Force Microscopy (NC-AFM 2009) and Casimir
2009 Satellite Worksho
An economical arterial-pulse-wave transducer
Transducer records arterial pulses externally. Device uses thin plastic membrane which is fluid coupled to pressure sensitive transistor. Transistor is connected to amplifier which, in turn, is connected to recorder. End section is threaded to accept suitable holder and contains pressure relief vent allowing transistor to sense only pressure levels greater than atmospheric
A scalable solid-state quantum computer based on quantum dot pillar structures
We investigate an optically driven quantum computer based on electric dipole
transitions within coupled single-electron quantum dots. Our quantum register
consists of a freestanding n-type pillar containing a series of pair wise
coupled asymmetric quantum dots, each with a slightly different energy
structure, and with grounding leads at the top and bottom of the pillar.
Asymmetric quantum wells confine electrons along the pillar axis and a
negatively biased gate wrapped around the center of the pillar allows for
electrostatic confinement in the radial direction. We self-consistently solve
coupled Schrodinger and Poisson equations and develop a design for a
three-qubit quantum register. Our results indicate that a single gate electrode
can be used to localize a single electron in each of the quantum dots. Adjacent
dots are strongly coupled by electric dipole-dipole interactions arising from
the dot asymmetry, thus enabling rapid computation rates. The dots are tailored
to minimize dephasing due to spontaneous emission and phonon scattering and to
maximize the number of computation cycles. The design is scalable to a large
number of qubits.Comment: 11 figure
Relationships between chlorophyll density and ocean radiance as measured by U2/OCS: Algorithms, examples and comparison
An ocean atmosphere radiative transfer process computation method which is suitable for determining lower boundary ocean albedo and other radiation components from spectral measurements of upwelling radiance taken from a high altitude platform is described. The method was applied to a set of color scanner data taken from slope water of the South Atlantic Bight to determine the influence of cholorophyll-a pigments in the sea on the ratio of upwelling radiance to down welling irradiance as a function of wavelength. The resulting chlorophyll concentrations are compared with measurements made by ships stationed along the flight path
Origin of synchronized traffic flow on highways and its dynamic phase transitions
We study the traffic flow on a highway with ramps through numerical
simulations of a hydrodynamic traffic flow model. It is found that the presence
of the external vehicle flux through ramps generates a new state of recurring
humps (RH). This novel dynamic state is characterized by temporal oscillations
of the vehicle density and velocity which are localized near ramps, and found
to be the origin of the synchronized traffic flow reported recently [PRL 79,
4030 (1997)]. We also argue that the dynamic phase transitions between the free
flow and the RH state can be interpreted as a subcritical Hopf bifurcation.Comment: 4 pages, source TeX file and 4 figures are tarred and compressed via
uufile
Electron beam evaporated high mobility thin films of indium antimonide
Electron beam evaporation and recrystallization of InSb thin films yielding high Hall mobilitie
- …
