1,128 research outputs found
One-loop non-renormalization results in EFTs
In Effective Field Theories (EFTs) with higher-dimensional operators many
anomalous dimensions vanish at the one-loop level for no apparent reason. With
the use of supersymmetry, and a classification of the operators according to
their embedding in super-operators, we are able to show why many of these
anomalous dimensions are zero. The key observation is that one-loop
contributions from superpartners trivially vanish in many cases under
consideration, making supersymmetry a powerful tool even for non-supersymmetric
models. We show this in detail in a simple U(1) model with a scalar and
fermions, and explain how to extend this to SM EFTs and the QCD Chiral
Langrangian. This provides an understanding of why most "current-current"
operators do not renormalize "loop" operators at the one-loop level, and allows
to find the few exceptions to this ubiquitous rule.Comment: Corrections made in Sec. 3.2 and Fig.
Observation of soliton explosions in a passively mode-locked fiber laser
Soliton explosions are among the most exotic dissipative phenomena studied in
mode-locked lasers. In this regime, a dissipative soliton circulating in the
laser cavity experiences an abrupt structural collapse, but within a few
roundtrips returns to its original quasi-stable state. In this work we report
on the first observation of such events in a fiber laser. Specifically, we
identify clear explosion signatures in measurements of shot-to-shot spectra of
an Yb-doped mode-locked fiber laser that is operating in a transition regime
between stable and noise-like emission. The comparatively long,
all-normal-dispersion cavity used in our experiments also permits direct
time-domain measurements, and we show that the explosions manifest themselves
as abrupt temporal shifts in the output pulse train. Our experimental results
are in good agreement with realistic numerical simulations based on an
iterative cavity map.Comment: 5 pages, 5 figures, submitte
Renormalization of dimension-six operators relevant for the Higgs decays
The discovery of the Higgs boson has opened a new window to test the SM
through the measurements of its couplings. Of particular interest is the
measured Higgs coupling to photons which arises in the SM at the one-loop
level, and can then be significantly affected by new physics. We calculate the
one-loop renormalization of the dimension-six operators relevant for
, which can be potentially important since
it could, in principle, give log-enhanced contributions from operator mixing.
We find however that there is no mixing from any current-current operator that
could lead to this log-enhanced effect. We show how the right choice of
operator basis can make this calculation simple. We then conclude that
can only be affected by RG mixing from
operators whose Wilson coefficients are expected to be of one-loop size, among
them fermion dipole-moment operators which we have also included.Comment: 21 pages. Improved version with h -> gamma Z results added and
structure of anomalous-dimension matrix determined further. Conclusions
unchange
On the shape of a pure O-sequence
An order ideal is a finite poset X of (monic) monomials such that, whenever M
is in X and N divides M, then N is in X. If all, say t, maximal monomials of X
have the same degree, then X is pure (of type t). A pure O-sequence is the
vector, h=(1,h_1,...,h_e), counting the monomials of X in each degree.
Equivalently, in the language of commutative algebra, pure O-sequences are the
h-vectors of monomial Artinian level algebras. Pure O-sequences had their
origin in one of Richard Stanley's early works in this area, and have since
played a significant role in at least three disciplines: the study of
simplicial complexes and their f-vectors, level algebras, and matroids. This
monograph is intended to be the first systematic study of the theory of pure
O-sequences. Our work, making an extensive use of algebraic and combinatorial
techniques, includes: (i) A characterization of the first half of a pure
O-sequence, which gives the exact converse to an algebraic g-theorem of Hausel;
(ii) A study of (the failing of) the unimodality property; (iii) The problem of
enumerating pure O-sequences, including a proof that almost all O-sequences are
pure, and the asymptotic enumeration of socle degree 3 pure O-sequences of type
t; (iv) The Interval Conjecture for Pure O-sequences (ICP), which represents
perhaps the strongest possible structural result short of an (impossible?)
characterization; (v) A pithy connection of the ICP with Stanley's matroid
h-vector conjecture; (vi) A specific study of pure O-sequences of type 2,
including a proof of the Weak Lefschetz Property in codimension 3 in
characteristic zero. As a corollary, pure O-sequences of codimension 3 and type
2 are unimodal (over any field); (vii) An analysis of the extent to which the
Weak and Strong Lefschetz Properties can fail for monomial algebras; (viii)
Some observations about pure f-vectors, an important special case of pure
O-sequences.Comment: iii + 77 pages monograph, to appear as an AMS Memoir. Several, mostly
minor revisions with respect to last year's versio
Higgs Inflation as a Mirage
We discuss a simple unitarization of Higgs inflation that is genuinely weakly
coupled up to Planckian energies. A large non-minimal coupling between the
Higgs and the Ricci curvature is induced dynamically at intermediate energies,
as a simple ratio of mass scales. Despite not being dominated by the Higgs
field, inflationary dynamics simulates the `Higgs inflation' one would get by
blind extrapolation of the low-energy effective Lagrangian, at least
qualitatively. Hence, Higgs inflation arises as an approximate `mirage' picture
of the true dynamics. We further speculate on the generality of this phenomenon
and show that, if Higgs-inflation arises as an effective description, the
details of the UV completion are necessary to extract robust quantitative
predictions.Comment: 21 pages, 2 figure
Estimasi Bangkitan Perjalanan Penduduk Perumahan Di Kelurahan Dadok Tunggul Hitam Kota Padang
Transportation problems appear as a result of the rapid population growth rate, creating housing areas and community activities, which generate trips. This study aims to determine the trip generated by the residential areas in the Village of Dadok Tunggul Hitam consisting Green Arya, Rumah Idaman Wisma Lestari, Perumdam, Permata Dadok, and Trisandi Indah settlements. These residential areas change the land function that would later cause problems. The community activities generate trips toward the city center. The secondary data were collected from the government agencies and the primary data were collected through direct Surveys. Variables used in this study are the size of the household, car ownership, income level, and the number of working family members. The data were then analyzed using descriptive techniques and linier regression method. The results show the number of trips produced each day and factors that influence the trips generated
A passive estimator of functional degradation in power mobility device users
© 2015 IEEE. This paper documents the development of a passive technique for assessing a power mobility device user's driving proficiency during everyday driving activities outside formal assessment conditions by therapists. This is approached by first building a model by means of an Artificial Neural Network to infer longer-Term destinations for discretized bouts of travel, and subsequently drawing cues indicative of decline in driving proficiency for the duration of point-To-point navigation rather than relying on instantaneously calculated metrics. This resultant quantity, which we refer to as 'functional degradation', can then provide therapists with additional information concerning user health or serve as a leveraging parameter in combinatory shared-control mobility frameworks. Experiments conducted by able-bodied users subject to simulated noise scaled to varying degrees of functional degradation reveal a quantitative correlation between these longer-Term proficiency metrics and the magnitude of degradation experienced; a promising outcome that sets the scene for a larger-scale clinical trial
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