455 research outputs found
Comment on "The Phenomenology of a Nonstandard Higgs Boson in W_L W_L Scattering"
We show that in Composite Higgs models, the coupling of the Higgs resonance
to a pair of bosons is weaker than the corresponding Standard Model
coupling, provided the Higgs arises from electroweak doublets only. This is
partly due to the effects of the nonlinear realization of the chiral symmetries
at the compositeness scale.Comment: 6 pages, BU-HEP 94-2
Antiresonances and Ultrafast Resonances in a Twin Photonic Oscillator
We consider the properties of the small-signal modulation response of
symmetry-breaking phase-locked states of twin coupled semiconductor lasers. The
extended stability and the varying asymmetry of these modes allows for the
introduction of a rich set of interesting modulation response features, such as
sharp resonances and anti-resonance as well as efficient modulation at very
high frequencies exceeding the free running relaxation frequencies by orders of
magnitude.Comment: 6 pages, 5 figure
Exceptional Points in Two Dissimilar Coupled Diode Lasers
We show the abundance of Exceptional Points in the generic asymmetric
configuration of two coupled diode lasers, under nonzero optical detuning and
differential pumping. We pinpoint the location of these points with respect to
the stability domains and the Hopf bifurcation points, in the solution space as
well as in the space of experimentally controlled parameters.Comment: 5 pages, 4 figure
Nonlinear Beam Propagation in a Class of Complex Non-PT -Symmetric Potentials
The subject of PT-symmetry and its areas of application have been blossoming
over the past decade. Here, we consider a nonlinear Schr\"odinger model with a
complex potential that can be tuned controllably away from being PT-symmetric,
as it might be the case in realistic applications. We utilize two parameters:
the first one breaks PT-symmetry but retains a proportionality between the
imaginary and the derivative of the real part of the potential; the second one,
detunes from this latter proportionality. It is shown that the departure of the
potential from the PT -symmetric form does not allow for the numerical
identification of exact stationary solutions. Nevertheless, it is of crucial
importance to consider the dynamical evolution of initial beam profiles. In
that light, we define a suitable notion of optimization and find that even for
non PT-symmetric cases, the beam dynamics, both in 1D and 2D -although prone to
weak growth or decay- suggests that the optimized profiles do not change
significantly under propagation for specific parameter regimes
Magnetic field imaging with atomic Rb vapor
We demonstrate the possibility of dynamic imaging of magnetic fields using
electromagnetically induced transparency in an atomic gas. As an experimental
demonstration we employ an atomic Rb gas confined in a glass cell to image the
transverse magnetic field created by a long straight wire. In this arrangement,
which clearly reveals the essential effect, the field of view is about 2 x 2
mm^2 and the field detection uncertainty is 0.14 mG per 10 um x 10 um image
pixel.Comment: 4 pages, 3 figure
Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity
Magnetic fields generated by human and animal organs, such as the heart,
brain and nervous system carry information useful for biological and medical
purposes. These magnetic fields are most commonly detected using
cryogenically-cooled superconducting magnetometers. Here we present the frst
detection of action potentials from an animal nerve using an optical atomic
magnetometer. Using an optimal design we are able to achieve the sensitivity
dominated by the quantum shot noise of light and quantum projection noise of
atomic spins. Such sensitivity allows us to measure the nerve impulse with a
miniature room-temperature sensor which is a critical advantage for biomedical
applications. Positioning the sensor at a distance of a few millimeters from
the nerve, corresponding to the distance between the skin and nerves in
biological studies, we detect the magnetic field generated by an action
potential of a frog sciatic nerve. From the magnetic field measurements we
determine the activity of the nerve and the temporal shape of the nerve
impulse. This work opens new ways towards implementing optical magnetometers as
practical devices for medical diagnostics.Comment: Main text with figures, and methods and supplementary informatio
Antiresonances and Ultrafast Resonances in a Twin Photonic Oscillator
https://ieeexplore.ieee.org/document/8630807We consider the properties of the small-signal modulation response of symmetry-breaking phase-locked states of twin coupled semiconductor lasers. The extended stability and the varying asymmetry of these modes allows for the introduction of a rich set of interesting modulation response features, such as sharp resonances and antiresonances as well as efficient modulation at very high frequencies exceeding the free running relaxation frequencies by orders of magnitude
Dynamical CP Violation and Flavour-Changing Processes
We investigate the phenomenological constraints on a model where, besides the
standard model Higgs sector, there is an effective new strong interaction
acting on the third generation of quarks and characterized by a -like
term. This term induces electroweak symmetry breaking and leads to
dynamical spontaneous CP violation. We show that the constraints coming from K
physics and the electric dipole moment of the neutron impose that the new
physics scale should be of the order of 35 TeV. Contrary to naive expectations,
the predictions of the model for B physics are very close to the standard model
ones. The main differences appear in processes involving the up quarks such as
mixing and in the electric dipole moment of the neutron, which
should be close to the experimental limit. Possible deviations from the
standard model predictions for CP asymmetries in B decays are also considered.Comment: LaTeX, 25 pages, 4 figure
Top quark associated production of topcolor pions at hadron colliders
We investigate the associated production of a neutral physical pion with top
quarks in the context of topcolor assisted technicolor. We find that single-top
associated production does not yield viable rates at either the Tevatron or
LHC. tt-associated production at the Tevatron is suppressed relative to
Standard Model ttH, but at the LHC is strongly enhanced and would allow for
easy observation of the main decay channels to bottom quarks, and possible
observation of the decay to gluons.Comment: 13 pages, 4 figures, submitted to PR
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