pinecone/core-2020-05-10-deduplication huggingface dataset:
Decoherence of charge states in double quantum dots due to cotunneling

Solid state quantum bits are a promising candidate for the realization of a
scalable quantum computer, however, they are usually strongly limited by
decoherence. We consider a double quantum dot charge qubit, whose basis states
are defined by the position of an additional electron in the system of two
laterally coupled quantum dots. The coupling of these two states can be
controlled externally by a quantum point contact between the two dots. We
discuss the decoherence through coupling to the electronic leads due to
cotunneling processes. We focus on a simple Gedanken experiment, where the
system is initially brought into a superposition and then the inter-dot
coupling is removed nonadiabatically. We treat the system by invoking the
Schrieffer-Wolff transformation in order to obtain a transformed Hamiltonian
describing the cotunneling, and then obtain the dynamics of the density matrix
using the Bloch-Redfield theory. As a main result, we show that there is energy
relaxation even in the absence of inter-dot coupling. This is in contrast to
what would be expected from the Spin-Boson model and is due to the fact that a
quantum dot is coupled to two distinct baths.Comment: 8 pages, 2 figure
Supersymmetric Scaling Violations (I). Solving the Supersymmetric DGLAP
  Evolution

We analize the renormalization group equations of supersymmetric QCD with N=1
for the evolution of parton distributions. For this purpose we develope a
simple recursive algorithm in x-space to include both regular regions and
supersymmetric regions in the evolution in the step approximation.
Supersymmetric distributions are generated within a radiative model, with
vanishing initial conditions for the superpartners. Here we focus on a scenario
with broken susy, characterized by a lighter gluino coupled to the standard
evolution and a decoupled scalar quark. Predictions for the all the
distributions are presented.Comment: 33 pages, 14 figures. revised final version, in press on Nucl. Phys.
The MSSM invisible Higgs in the light of dark matter and g-2

Giving up the assumption of the gaugino mass unification at the GUT scale,
the latest LEP and Tevatron data still allow the lightest supersymmetric Higgs
to have a large branching fraction into invisible neutralinos. Such a Higgs may
be difficult to discover at the LHC and is practically unreachable at the
Tevatron. We argue that, for some of these models to be compatible with the
relic density, light sleptons with masses not far above the current limits are
needed. There are however models that allow for larger sleptons masses without
being in conflict with the relic density constraint. This is possible because
these neutralinos can annihilate efficiently through a Z-pole. We also find
that many of these models can nicely account, at the 2\sigma level, for the
discrepancy in the latest g-2 measurement. However, requiring consistency with
the g-2 at the 1\sigma level, excludes models that lead to the largest Higgs
branching fraction into LSP's. In all cases one expects that even though the
Higgs might escape detection, one would have a rich SUSY phenomenology even at
the Tevatron, through the production of charginos and neutralinos.Comment: 16 pages and 5 figures. New references added, text and figures
  unchange
Evidence that the a0(980) and f0(980) are not elementary particles

We study the interesting problem of whether it is possible to distinguish
composite from elementary particles. In particular we generalize a
model-independent approach of S. Weinberg to the case of unstable particles.
This allows us to apply our formalism to the case of the a0(980) and f0(980)
resonances and to address the question whether these particles are
predominantly genuine, confined quark states (of $\bar q q$ or $qq\bar q\bar q$
structure) or governed by mesonic components.Comment: 15 pages, 4 Figure
Flavor and CP violating Z exchange and the rate asymmetry in B --> phi
  K_S

Recent measurements of time dependent CP asymmetry in B --> phi K_S, if
confirmed, would indicate a new source of CP violation. We examine flavor
violating tree-level Z currents in models with extra down-type quark singlets
that arise naturally in string compactified gauge groups like E_6. We evaluate
the new operators at the scale mu = m_b in NLO, and using QCD improved
factorization to describe B --> phi K_S, find the allowed range of parameters
for rho and psi, the magnitude and phase of the flavor violating parameter
U_{bs}. This allowed range does satisfy the constraint from flavor changing
process b --> s l+ l- . However, further improvement in measurement of these
rates could severely constrain the model.Comment: 15 pages, Latex, 2 postscript figures. Sections 2 and 3 are
  reordered. More references are added. Version to be published in PL
Unifying the PST and the auxiliary tensor field formulations of 4D
  self-duality

We unify the Lorentz- and O(2) duality-covariant approach to 4D self-dual
theories by Pasti, Sorokin and Tonin (PST) with the formulation involving an
auxiliary tensor field. We present the basic features of the new hybrid
approach, including symmetries of the relevant generalized PST action. Its
salient peculiarity is the unique form of the realization of the PST gauge
symmetries. The corresponding transformations do not affect the auxiliary
tensor field, which guarantees the self-duality of the nonlinear actions in
which the O(2) invariant interactions are constructed out of the tensor field.Comment: 0 + 12 pages, typos corrected; published versio
Problematic aspects of Kaluza-Klein excitations in multidimensional
  models with Einstein internal spaces

We consider Kaluza-Klein (KK) models where internal spaces are compact
Einstein spaces. These spaces are stabilized by background matter (e.g.,
monopole form-fields). We perturb this background by a compact matter source
(e.g., the system of gravitating masses) with the zero pressure in the
external/our space and an arbitrary pressure in the internal space. We show
that the Einstein equations are compatible only if the matter source is smeared
over the internal space and perturbed metric components do not depend on
coordinates of extra dimensions. The latter means the absence of KK modes
corresponding to the metric fluctuations. Maybe, the absence of KK particles in
LHC experiments is explained by such mechanism.Comment: 10 pages, no figure
Thanatology in Protoplanetary Discs: the combined influence of Ohmic,
  Hall, and ambipolar diffusion on dead zones

Protoplanetary discs are poorly ionised due to their low temperatures and
high column densities, and are therefore subject to three "non-ideal"
magnetohydrodynamic effects: Ohmic dissipation, ambipolar diffusion, and the
Hall effect. The existence of magnetically driven turbulence in these discs has
been a central question since the discovery of the magnetorotational
instability. Early models considered Ohmic diffusion only and led to a scenario
of layered accretion, in which a magnetically "dead" zone in the disc midplane
is embedded within magnetically "active" surface layers at distances ~1-10 au
from the central protostellar object. Recent work has suggested that a
combination of Ohmic dissipation and ambipolar diffusion can render both the
midplane and surface layers of the disc inactive and that torques due to
magnetically driven outflows are required to explain the observed accretion
rates. We reassess this picture by performing three-dimensional numerical
simulations that include, for the first time, all three non-ideal MHD effects.
We find that the Hall effect can generically "revive" dead zones by producing a
dominant azimuthal magnetic field and a large-scale Maxwell stress throughout
the midplane, provided the angular velocity and magnetic field satisfy Omega.B
> 0. The attendant large magnetic pressure modifies the vertical density
profile and substantially increases the disc scale height beyond its
hydrostatic value. Outflows are produced, but are not necessary to explain
accretion rates <10^{-7} Msun/yr. The flow in the disc midplane is essentially
laminar, suggesting that dust sedimentation may be efficient. These results
demonstrate that, if the MRI is relevant for driving mass accretion in
protoplanetary discs, one must include the Hall effect to obtain even
qualitatively correct results.Comment: 16 pages, 18 figures, 3 tables, accepted for publication in Astronomy
  & Astrophysic
Effect of anisotropy in the $S=1$ underscreened Kondo lattice

We study the effect of crystal field anisotropy in the underscreened $S=1$
Kondo lattice model. Starting from the two orbital Anderson lattice model and
including a local anisotropy term, we show, through Schrieffer-Wolff
transformation, that local anisotropy is equivalent to an anisotropic Kondo
interaction ($J_{\parallel} \neq{J_{\perp}}$). The competition and coexistence
between ferromagnetism and Kondo effect in this effective model is studied
within a generalized mean-field approximation. Several regimes are obtained,
depending on the parameters, exhibiting or not coexistence of magnetic order
and Kondo effect. Particularly, we show that a re-entrant Kondo phase at low
temperature can be obtained. We are also able to describe phases where the
Kondo temperature is smaller than the Curie temperature ($T_K<T_C$). We propose
that some aspects of uranium and neptunium compounds that present coexistence
of Kondo effect and ferromagnetism, can be understood within this model.Comment: 7 pages, 3 figure
Planck intermediate results. XXIII. Galactic plane emission components
  derived from Planck with ancillary data

Planck data when combined with ancillary data provide a unique opportunity to
separate the diffuse emission components of the inner Galaxy. The purpose of
the paper is to elucidate the morphology of the various emission components in
the strong star-formation region lying inside the solar radius and to clarify
the relationship between the various components. The region of the Galactic
plane covered is l=300-0-60deg where star-formation is highest and the emission
is strong enough to make meaningful component separation. The latitude widths
in this longitude range lie between 1deg and 2deg, which correspond to FWHM
z-widths of 100-200pc at a typical distance of 6kpc. The four emission
components studied here are synchrotron, free-free, anomalous microwave
emission (AME), and thermal (vibrational) dust emission. These components are
identified by constructing spectral energy distributions (SEDs) at positions
along the Galactic plane using the wide frequency coverage of Planck
(28.4-857GHz) in combination with low-frequency radio data at 0.408-2.3GHz plus
WMAP data at 23-94GHz, along with far-infrared (FIR) data from DIRBE and IRAS.
The free-free component is determined from radio recombination line (RRL) data.
AME is found to be comparable in brightness to the free-free emission on the
Galactic plane in the frequency range 20-40GHz with a width in latitude similar
to that of the thermal dust; it comprises 45+/-1% of the total 28.4GHz emission
in the longitude range l=300-0-60deg. The free-free component is the narrowest,
reflecting the fact that it is produced by current star-formation as traced by
the narrow distribution of OB stars. It is the dominant emission on the plane
between 60 and 100GHz. RRLs from this ionized gas are used to assess its
distance, leading to a free-free z-width of FWHM ~100pc...(abridged)Comment: 28 pages, A&A (accepted), on behalf of Planck Collaboration. Minor
  formatting and reference update
The Good, the Bad and the Ugly: Statistical quality assessment of SZ
  detections

We examine three approaches to the problem of source classification in
catalogues. Our goal is to determine the confidence with which the elements in
these catalogues can be distinguished in populations on the basis of their
spectral energy distribution (SED). Our analysis is based on the projection of
the measurements onto a comprehensive SED model of the main signals in the
considered range of frequencies. We first first consider likelihood analysis,
which half way between supervised and unsupervised methods. Next, we
investigate an unsupervised clustering technique. Finally, we consider a
supervised classifier based on Artificial Neural Networks. We illustrate the
approach and results using catalogues from various surveys. i.e., X-Rays
(MCXC), optical (SDSS) and millimetric (Planck Sunyaev-Zeldovich (SZ)). We show
that the results from the statistical classifications of the three methods are
in very good agreement with each others, although the supervised neural
network-based classification shows better performances allowing the best
separation into populations of reliable and unreliable sources in catalogues.
The latest method was applied to the SZ sources detected by the Planck
satellite. It led to a classification assessing and thereby agreeing with the
reliability assessment published in the Planck SZ catalogue. Our method could
easily be applied to catalogues from future large survey such as SRG/eROSITA
and Euclid.Comment: Submitted to A&A, 15 pages 40 figure
Local BRST cohomology in Einstein-Yang-Mills theory

We analyse in detail the local BRST cohomology in Einstein-Yang-Mills theory using the antifield formalism. We do not restrict the Lagrangian to be the sum of the standard Hilbert and Yang-Mills Lagrangians, but allow for more general diffeomorphism and gauge invariant actions. The analysis is carried out in all spacetime dimensions larger than 2 and for all ghost numbers. This covers the classification of all candidate anomalies, of all consistent deformations of the action, as well as the computation of the (equivariant) characteristic cohomology, i.e. the cohomology of the spacetime exterior derivative in the space of (gauge invariant) local differential forms modulo forms that vanish on-shell. We show in particular that for a semi-simple Yang-Mills gauge group the antifield dependence can be entirely removed both from the consistent deformations of the Lagrangian and from the candidate anomalies. Thus, the allowed deformations of the action necessarily preserve the gauge structure, while the only candidate anomalies are those provided by previous works not dealing with antifields, and by ``topological" candidate anomalies which are present only in special spacetime dimensions (6,9,10,11,...). This result no longer holds in presence of abelian factors where new candidate anomalies and deformations of the action can be constructed out of the conserved Noether currents (if any). The Noether currents themselves are shown to be covariantizable, with a few exceptions discussed as well
Three loop MSbar renormalization of the Curci-Ferrari model and the
  dimension two BRST invariant composite operator in QCD

The massless Curci-Ferrari model with N_f flavours of quarks is renormalized
to three loops in the MSbar scheme in an arbitrary covariant gauge with
parameter alpha. The renormalization of the BRST invariant dimension two
composite operator, 1/2 (A^a_\mu)^2 - alpha \bar{c}^a c^a, which corresponds to
the mass operator in the massive Curci-Ferrari model, is determined by
renormalizing the Green's function where the operator is inserted in a ghost
two-point function. Consequently the anomalous dimension of the QCD Landau
gauge operator, 1/2 (A^a_\mu)^2, and the (gauge independent) photon mass
anomalous dimension in QED are both deduced at three loops.Comment: 11 latex page
Quasi-Exactly Solvable Spin 1/2 Schr\"odinger Operators

The algebraic structures underlying quasi-exact solvability for spin 1/2
Hamiltonians in one dimension are studied in detail. Necessary and sufficient
conditions for a matrix second-order differential operator preserving a space
of wave functions with polynomial components to be equivalent to a \sch\
operator are found. Systematic simplifications of these conditions are
analyzed, and are then applied to the construction of several new examples of
multi-parameter QES spin 1/2 Hamiltonians in one dimension.Comment: 32 pages, LaTeX2e using AMS-LaTeX packag
Planck 2013 results. XXIX. The Planck catalogue of Sunyaev-Zeldovich
  sources: Addendum

We update the all-sky Planck catalogue of 1227 clusters and cluster
candidates (PSZ1) published in March 2013, derived from Sunyaev-Zeldovich (SZ)
effect detections using the first 15.5 months of Planck satellite observations.
Addendum. We deliver an updated version of the PSZ1 catalogue, reporting the
further confirmation of 86 Planck-discovered clusters. In total, the PSZ1 now
contains 947 confirmed clusters, of which 214 were confirmed as newly
discovered clusters through follow-up observations undertaken by the Planck
Collaboration. The updated PSZ1 contains redshifts for 913 systems, of which
736 (~80.6%) are spectroscopic, and associated mass estimates derived from the
Y_z mass proxy. We also provide a new SZ quality flag, derived from a novel
artificial neural network classification of the SZ signal, for the remaining
280 candidates. Based on this assessment, the purity of the updated PSZ1
catalogue is estimated to be 94%. In this release, we provide the full updated
catalogue and an additional readme file with further information on the Planck
SZ detections.Comment: Submitted to A&
Very Large Telescope observations of Gomez's Hamburger: Insights into a
  young protoplanet candidate

Planets are thought to form in the gas and dust disks around young stars. In
particular, it has been proposed that giant planets can form through the
gravitational instability of massive extended disks around intermediate-mass
stars. However, we still lack direct observations to constrain this mechanism.
We have spatially resolved the 8.6 and 11.2 $\mu$m emission of a massive
protoplanetary disk seen edge on around an A star, Gomez's Hamburger (GoHam),
using VISIR at the Very Large Telescope. A compact region situated at a
projected distance of $350\pm50$ AU south of the central star is found to have
a reduced emission.This asymmetry is fully consistent with the presence of a
cold density structure, or clump, identified in earlier CO observations, and we
derive physical characteristics consistent with those observations: a mass of
0.8-11.4 Jupiter masses (for a dust-to-gas mass ratio of 0.01), a radius of
about 10$^2$ astronomical units, and a local density of about $10^{7}$
cm$^{-3}$. Based on this evidence, we argue that this clump, which we call
GoHam b, is a promising candidate for a young protoplanet formed by
gravitational instability that might be representative of the precursors of
massive planets observed around A stars, such as HR 8799 or Beta pictoris. More
detailed studies at high angular resolution are needed to better constrain the
physical properties of this object to confirm this proposal.Comment: 7 Pages, accepted for publication as a Letter in A&
HII region G46.5-0.2: the interplay between ionizing radiation,
  molecular gas and star formation

HII regions are particularly interesting because they can generate dense
layers of gas and dust, elongated columns or pillars of gas pointing towards
the ionizing sources, and cometary globules of dense gas, where triggered star
formation can occur. Understanding the interplay between the ionizing radiation
and the dense surrounding gas is very important to explain the origin of these
peculiar structures, and hence to characterize triggered star formation.
G46.5-0.2 (G46), a poorly studied galactic HII region located at about 4 kpc,
is an excellent target to perform this kind of studies. Using public molecular
data extracted from the Galactic Ring Survey (13CO J=1-0) and from the James
Clerk Maxwell Telescope data archive (12CO, 13CO, C18O J=3-2, HCO+ and HCN
J=4-3), and infrared data from the GLIMPSE and MIPSGAL surveys, we perform a
complete study of G46, its molecular environment and the young stellar objects
placed around it. We found that G46, probably excited by an O7V star, is
located close to the edge of the GRSMC G046.34-00.21 molecular cloud. It
presents a horse-shoe morphology opening in direction of the cloud. We observed
a filamentary structure in the molecular gas likely related to G46 and not
considerable molecular emission towards its open border. We found that about
10' towards the southwest of G46 there are some pillar-like features, shining
at 8 um and pointing towards the HII region open border. We propose that the
pillar-like features were carved and sculpted by the ionizing flux from G46. We
found several young stellar objects likely embedded in the molecular cloud
grouped in two main concentrations: one, closer to the G46 open border
consisting of Class II type sources, and other one mostly composed by Class I
type YSOs located just ahead the pillars-like features, strongly suggesting an
age gradient in the YSOs distribution.Comment: Accepted for publication in The Astronomical Journal (April 14,
  2015). Some figures were degraded to reduce file siz
IRAS 18357-0604 – an analogue of the galactic yellow hypergiant IRC +10420?

Context. Yellow hypergiants represent a short-lived evolutionary episode experienced by massive stars as they transit to and from a red supergiant phase. As such, their properties provide a critical test of stellar evolutionary theory, while recent observations unexpectedly suggest that a subset may explode as Type II supernovae. Aims. The galactic yellow hypergiant IRC +10420 is a cornerstone system for understanding this phase since it is the strongest post-RSG candidate known, has demonstrated real-time evolution across the Hertzsprung-Russell diagram and been subject to extensive mass loss. In this paper we report on the discovery of a twin of IRC +10420 - IRAS 18357-0604. Methods. Optical and near-IR spectroscopy are used to investigate the physical properties of IRAS 18357-0604 and also provide an estimate of its systemic velocity, while near- to mid-IR photometry probes the nature of its circumstellar environment. Results. These observations reveal pronounced spectral similarities between IRAS 18357-0604 and IRC +10420, suggesting comparable temperatures and wind geometries. IR photometric data reveals a similarly dusty circumstellar environment, although historical mass loss appears to have been heavier in IRC +10420. The systemic velocity implies a distance compatible with the red supergiant-dominated complex at the base of the Scutum Crux arm; the resultant luminosity determination is consistent with a physical association but suggests a lower initial mass than inferred for IRC +10420 (≲20 M⊙ versus ~40 M⊙). Evolutionary predictions for the physical properties of supernova progenitors derived from ~18–20 M⊙ stars – or ~12–15 M⊙ stars that have experienced enhanced mass loss as red supergiants – compare favourably with those of IRAS 18357-0604, which in turn appears to be similar to the the progenitor of SN2011dh; it may therefore provide an important insight into the nature of the apparently H-depleted yellow hypergiant progenitors of some Type IIb SNe.This research is partially supported by the Spanish Ministerio de Economía y Competitividad (Mineco) under grants AYA2010-21697-C05-05 and AYA2012-39364-C02-02. The AAT observations have been supported by the OPTICON project (observing proposal 2012/A015), which is funded by the European Commission under the Seventh Framework Programme (FP7)