7,635 research outputs found
On Cyclic Harmonic Oscillators
It is proven that the energy of a quantum mechanical harmonic oscillator with
a generically time-dependent but cyclic frequency, , cannot decrease on the average if the system is originally in a
stationary state, after the system goes through a full cycle. The energy
exchange always takes place in the direction from the macroscopic system
(environment) to the quantum microscopic system.Comment: Latex file, 14 pages, 3 figures, minor correction made in Section
A Minimal SU(5) SuperGUT in Pure Gravity Mediation
The lack of evidence for low-scale supersymmetry suggests that the scale of
supersymmetry breaking may be higher than originally anticipated. However,
there remain many motivations for supersymmetry including gauge coupling
unification and a stable dark matter candidate. Models like pure gravity
mediation (PGM) evade LHC searches while still providing a good dark matter
candidate and gauge coupling unification. Here, we study the effects of PGM if
the input boundary conditions for soft supersymmetry breaking masses are pushed
beyond the unification scale and higher dimensional operators are included. The
added running beyond the unification scale opens up the parameter space by
relaxing the constraints on . If higher dimensional operators
involving the SU(5) adjoint Higgs are included, the mass of the heavy gauge
bosons of SU(5) can be suppressed leading to proton decay, ,
that is within reach of future experiments. Higher dimensional operators
involving the supersymmetry breaking field can generate additional
contributions to the A- and B-terms of order . The threshold effects
involving these A- and B-terms significantly impact the masses of the gauginos
and can lead to a bino LSP. In some regions of parameter space the bino can be
degenerate with the wino or gluino and give an acceptable dark matter relic
density.Comment: 37 pages, 27 figure
Low-Scale D-term Inflation and the Relaxion
We present a dynamical cosmological solution that simultaneously accounts for
the early inflationary stage of the Universe and solves the supersymmetric
little hierarchy problem via the relaxion mechanism. First, we consider an
inflationary potential arising from the -term of a new gauge symmetry
with a Fayet--Iliopolous term, that is independent of the relaxion. A
technically natural, small gauge coupling, , allows
for a low Hubble scale of inflation, GeV, which is shown to
be consistent with Planck data. This feature is then used to realize a
supersymmetric two-field relaxion mechanism, where the second field is
identified as the inflaton provided that GeV. The inflaton
controls the relaxion barrier height allowing the relaxion to evolve in the
early Universe and scan the supersymmetric soft masses. After electroweak
symmetry is broken, the relaxion settles at a local supersymmetry-breaking
minimum with a range of -term values that can naturally explain
supersymmetric soft mass scales up to GeV.Comment: 37 pages, 4 figure
Naturalizing Supersymmetry with a Two-Field Relaxion Mechanism
We present a supersymmetric version of a two-field relaxion model that
naturalizes tuned versions of supersymmetry. This arises from a relaxion
mechanism that does not depend on QCD dynamics and where the relaxion potential
barrier height is controlled by a second axion-like field. During the
cosmological evolution, the relaxion rolls with a nonzero value that breaks
supersymmetry and scans the soft supersymmetric mass terms. Electroweak
symmetry is broken after the soft masses become of order the supersymmetric
Higgs mass term and causes the relaxion to stop rolling for superpartner masses
up to GeV. This can explain the tuning in supersymmetric models,
including split-SUSY models, while preserving the QCD axion solution to the
strong CP problem. Besides predicting two very weakly-coupled axion-like
particles, the supersymmetric spectrum may contain an extra Goldstino, which
could be a viable dark matter candidate.Comment: 33 pages, 3 figures; v2: bounds and figures correcte
Beating the Standard Quantum Limit with Four Entangled Photons
Precision measurements are important across all fields of science. In
particular, optical phase measurements can be used to measure distance,
position, displacement, acceleration and optical path length. Quantum
entanglement enables higher precision than would otherwise be possible. We
demonstrate an optical phase measurement with an entangled four photon
interference visibility greater than the threshold to beat the standard quantum
limit--the limit attainable without entanglement. These results open the way
for new high-precision measurement applications.Comment: 5 pages, 4 figures Author name was slightly modifie
Beyond the CMSSM without an Accelerator: Proton Decay and Direct Dark Matter Detection
We consider two potential non-accelerator signatures of generalizations of
the well-studied constrained minimal supersymmetric standard model (CMSSM). In
one generalization, the universality constraints on soft supersymmetry-breaking
parameters are applied at some input scale below the grand unification
(GUT) scale , a scenario referred to as `sub-GUT'. The other
generalization we consider is to retain GUT-scale universality for the squark
and slepton masses, but to relax universality for the soft
supersymmetry-breaking contributions to the masses of the Higgs doublets. As
with other CMSSM-like models, the measured Higgs mass requires supersymmetric
particle masses near or beyond the TeV scale. Because of these rather heavy
sparticle masses, the embedding of these CMSSM-like models in a minimal SU(5)
model of grand unification can yield a proton lifetime consistent with current
experimental limits, and may be accessible in existing and future proton decay
experiments. Another possible signature of these CMSSM-like models is direct
detection of supersymmetric dark matter. The direct dark matter scattering rate
is typically below the reach of the LUX-ZEPLIN (LZ) experiment if is
close to , but may lie within its reach if
GeV. Likewise, generalizing the CMSSM to allow non-universal
supersymmetry-breaking contributions to the Higgs offers extensive
possibilities for models within reach of the LZ experiment that have long
proton lifetimes.Comment: 42 pages, 15 figure
A reliable begomovírus inoculation method for screening Lycopersicon esculentum lines.
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Previous issue date: 2007-12-1
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