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Soft supersymmetry breaking as the sole origin of neutrino masses and lepton number violation
We discuss a scenario in which the supergravity induced soft terms,
conventionally used for breaking supersymmetry, also lead to non-zero Majorana
neutrino masses. The soft terms lead to the spontaneous violation of the lepton
number at the gravitino mass scale which in turn leads to (i) the
Majorana masses of for the right-handed neutrinos and (ii)
the -parity breaking at the same scale. The former contributes to light
neutrino masses through the type I seesaw mechanism, while the latter adds to
it through neutrino-neutralino mixing. Both contributions can scale inversely
with respect to given that gaugino and Higgsino masses are also of
order . Together, these two contributions adequately explain observed
neutrino masses and mixing. One realization of the scenario also naturally
leads to a parameter of . Despite the lepton number
symmetry breaking close to the weak scale, the Majoron in the model exhibits
very weak coupling to leptons, satisfying existing constraints on
Majoron-lepton interactions. The right-handed neutrinos in the model have a
large coupling to Higgsinos. This coupling and the relatively large heavy-light
neutrino mixing induced through the seesaw mechanism may lead to the observable
signals at colliders in terms of displaced vertices.Comment: V2: Added discussion, updated reference list, published versio
From Proof-theoretic Validity to Base-extension Semantics for Intuitionistic Propositional Logic
Proof-theoretic semantics (P-tS) is the approach to meaning in logic based on
\emph{proof} (as opposed to truth). There are two major approaches to P-tS:
proof-theoretic validity (P-tV) and base-extension semantics (B-eS). The former
is a semantics of arguments, and the latter is a semantics of logical constants
in a logic. This paper demonstrates that the B-eS for intuitionistic
propositional logic (IPL) encapsulates the declarative content of a basic
version of P-tV. Such relationships have been considered before yielding
incompleteness results. This paper diverges from these approaches by accounting
for the constructive, hypothetical setup of P-tV. It explicates how the B-eS
for IPL works
Modeling of Subwavelength Gratings: Near-Field Behavior
Subwavelength gratings, with period shorter than the incident wavelength,
have garnered significant attention in the fields of photonics,
optoelectronics, and image sensor technology. In this research, we delve into
the scattering characteristics of these gratings by employing the 2-dimensional
point dipole approximation. Additionally, we propose a version of perturbation
theory that relies on Fourier decomposition to obtain analytical expressions
for the near-field behavior. We validate our models using numerical techniques
such as boundary and finite element analysis. Notably, we explore how
parameters like the grating period and slit width affect field enhancements. We
demonstrate that our models produce qualitatively accurate results even for
narrow slits.Comment: 16 pages, 9 figures, bibliography 29 source
Topology optimization and boundary observation for clamped plates
We indicate a new approach to the optimization of the clamped plates with
holes. It is based on the use of Hamiltonian systems and the penalization of
the performance index. The alternative technique employing the penalization of
the state system, cannot be applied in this case due to the (two) Dirichlet
boundary conditions. We also include numerical tests exhibiting both shape and
topological modifications, both creating and closing holes
General Relativistic Chronometry with Clocks on Ground and in Space
One of geodesy's main tasks is to determine the gravity field of the Earth.
High precision clocks have the potential to provide a new tool in a global
determination of the Earth's gravitational potential based on the gravitational
redshift. Towards this clock-based gravimetry or chronometry in stationary
spacetimes, exact expressions for the relativistic redshift and the timing
between observers in various configurations are derived. These observers are
assumed to be equipped with standard clocks and move along arbitrary
worldlines. It is shown that redshift measurements, involving clocks on ground
and/or in space, can be used to determine the (mass) multipole moments of the
underlying spacetime. Results shown here are in agreement with the Newtonian
potential determination from, e.g., the so-called energy approach. The
framework of chronometric geodesy is exemplified in different exact vacuum
spacetimes for illustration and future gravity field recovery missions may use
clock comparisons as an additional data channel for advanced data fusion.Comment: 15 pages, 4 figure
The evolution of collision debris near the secular resonance and its role in the origin of terrestrial water
This work presents novel findings that broadens our understanding of the
amount of water that can be transported to Earth. The key innovation lies in
the combined usage of Smoothed Particle Hydrodynamics (SPH) and -body codes
to assess the role of collision fragments in water delivery. We also present a
method for generating initial conditions that enables the projectile to impact
at the designated location on the target's surface with the specified velocity.
The primary objective of this study is to simulate giant collisions between two
Ceres-sized bodies by SPH near the secular resonance and follow the
evolution of the ejected debris by numerical -body code. With our method 6
different initial conditions for the collision were determined and the
corresponding impacts were simulated by SPH. Examining the orbital evolution of
the debris ejected after collisions, we measured the amount of water delivered
to Earth, which is broadly 0.001 ocean equivalents of water, except in one case
where one large body transported 7\% oceans of water to the planet. Based on
this, and taking into account the frequency of collisions, the amount of
delivered water varies between 1.2 and 8.3 ocean's worth of water, depending on
the primordial disk mass. According to our results, the prevailing external
pollution model effectively accounts for the assumed water content on Earth,
whether it's estimated at 1 or 10 ocean's worth of water.Comment: 15 pages, 13 figure
Tunable ultrafast thermionic emission from femtosecond-laser hot spot on a metal surface: role of laser polarization and angle of incidence
Ultrafast laser induced thermionic emission from metal surfaces has several
applications. Here, we investigate the role of laser polarization and angle of
incidence on the ultrafast thermionic emission process from laser driven gold
coated glass surface. The spatio-temporal evolution of electron and lattice
temperatures are obtained using an improved three-dimensional (3D)
two-temperature model (TTM) which takes into account the 3D laser pulse profile
focused obliquely onto the surface. The associated thermionic emission features
are described through modified Richardson-Dushman equation, including dynamic
space charge effects and are included self-consistently in our numerical
approach. We show that temperature dependent reflectivity influences laser
energy absorption. The resulting peak electron temperature on the metal surface
monotonically increases with angle of incidence for P polarization, while for S
polarization it shows opposite trend. We observe that thermionic emission
duration shows strong dependence on angle of incidence and contrasting
polarization dependent behaviour. The duration of thermionic current shows
strong correlation to the intrinsic electron-lattice thermalization time, in a
fluence regime well below the damage threshold of gold. The observations and
insights have important consequences in designing ultrafast thermionic emitters
based on a metal based architecture.Comment: 17 pages, 7 figures, 1 tabl
No Evidence for More Earth-sized Planets in the Habitable Zone of Kepler's M versus FGK Stars
Reliable detections of Earth-sized planets in the habitable zone remain
elusive in the Kepler sample, even for M dwarfs. The Kepler sample was once
thought to contain a considerable number of M dwarf stars ( K), which hosted enough Earth-sized ( R) planets to
estimate their occurrence rate () in the habitable zone. However,
updated stellar properties from Gaia have shifted many Kepler stars to earlier
spectral type classifications, with most stars (and their planets) now measured
to be larger and hotter than previously believed. Today, only one
partially-reliable Earth-sized candidate remains in the optimistic habitable
zone, and zero in the conservative zone. Here we performed a new investigation
of Kepler's Earth-sized planets orbiting M dwarf stars, using occurrence rate
models with considerations of updated parameters and candidate reliability.
Extrapolating our models to low instellations, we found an occurrence rate of
for the conservative habitable zone
(and for the optimistic), consistent with
previous works when considering the large uncertainties. Comparing these
estimates to those from similarly comprehensive studies of Sun-like stars, we
found that the current Kepler sample does not offer evidence to support an
increase in from FGK to M stars. While the Kepler sample is too
sparse to resolve an occurrence trend between early and mid-to-late M dwarfs
for Earth-sized planets, studies including larger planets and/or data from the
K2 and TESS missions are well-suited to this task.Comment: 22 pages, 11 figures, 2 tables; Accepted for publication in A
Language Models as Zero-Shot Trajectory Generators
Large Language Models (LLMs) have recently shown promise as high-level
planners for robots when given access to a selection of low-level skills.
However, it is often assumed that LLMs do not possess sufficient knowledge to
be used for the low-level trajectories themselves. In this work, we address
this assumption thoroughly, and investigate if an LLM (GPT-4) can directly
predict a dense sequence of end-effector poses for manipulation skills, when
given access to only object detection and segmentation vision models. We study
how well a single task-agnostic prompt, without any in-context examples, motion
primitives, or external trajectory optimisers, can perform across 26 real-world
language-based tasks, such as "open the bottle cap" and "wipe the plate with
the sponge", and we investigate which design choices in this prompt are the
most effective. Our conclusions raise the assumed limit of LLMs for robotics,
and we reveal for the first time that LLMs do indeed possess an understanding
of low-level robot control sufficient for a range of common tasks, and that
they can additionally detect failures and then re-plan trajectories
accordingly. Videos, code, and prompts are available at:
https://www.robot-learning.uk/language-models-trajectory-generators.Comment: 19 pages, 21 figure
Uniform representation of the turbulent velocity profile in an open channel
A uniform representation of the mean turbulent velocity profile in the sum of
a wall function and a wake function is applied to an open channel,
quantitatively determining its components. The open channel is thus found to
coherently fit in to the same theoretical picture previously drawn for plane
Couette, plane closed channel and circular pipe flow, and to share with them a
universal law of the wall and a universal logarithmic law with a common value
of von K\'arm\'an's constant.Comment: submitted to the Journal of Fluid Mechanic