2,231 research outputs found
Form factor approach to dynamical correlation functions in critical models
We develop a form factor approach to the study of dynamical correlation
functions of quantum integrable models in the critical regime. As an example,
we consider the quantum non-linear Schr\"odinger model. We derive
long-distance/long-time asymptotic behavior of various two-point functions of
this model. We also compute edge exponents and amplitudes characterizing the
power-law behavior of dynamical response functions on the particle/hole
excitation thresholds. These last results confirm predictions based on the
non-linear Luttinger liquid method. Our results rely on a first principles
derivation, based on the microscopic analysis of the model, without invoking,
at any stage, some correspondence with a continuous field theory. Furthermore,
our approach only makes use of certain general properties of the model, so that
it should be applicable, with possibly minor modifications, to a wide class of
(not necessarily integrable) gapless one dimensional Hamiltonians.Comment: 33 page
OGLE-2002-BLG-360: from a gravitational microlensing candidate to an overlooked red transient
OGLE-2002-BLG-360 was discovered as a microlensing candidate by the OGLE-III
project. The subsequent light curve however clearly showed that the brightening
of the object could not have resulted from the gravitational microlensing
phenomenon. We aim to explain the nature of OGLE-2002-BLG-360 and its eruption
observed in 2002--2006. The observational data primarily come from the archives
of the OGLE project, which monitored the object in 2001--2009. The archives of
the MACHO and MOA projects also provided us with additional data obtained in
1995--99 and 2000--2005, respectively. These data allowed us to analyse the
light curve of the object during its eruption, as well as the potential
variability of its progenitor. In the archives of several infrared surveys,
namely 2MASS, MSX, Spitzer, AKARI, WISE, and VVV, we found measurements of the
object, which allowed us to study the spectral energy distribution (SED) of the
object. We constructed a simple model of a star surrounded by a dusty envelope,
which was used to interpret the observed SED. Our analysis of the data clearly
shows that OGLE-2002-BLG-360 was most probably a red transient, i.e. an object
similar in nature to V838 Mon, whose eruption was observed in 2002. The SED in
all phases, i.e. progenitor, eruption, and remnant, was dominated by infrared
emission, which we interpret as evidence of dust formation in an intense mass
outflow. Since 2009 the object has been completely embedded in dust. We suggest
that the progenitor of OGLE-2002-BLG-360 was a binary, which had entered the
common-envelope phase a long time (at least decades) before the observed
eruption, and that the eruption resulted from the final merger of the binary
components. We point out similarities between OGLE-2002-BLG-360 and CK Vul,
whose eruption was observed in 1670--72, and this strengthens the hypothesis
that CK Vul was also a red transient.Comment: accepted in A&
Lowest Open Channels, Bound States, and Narrow Resonances of Dipositronium
The constraints imposed by symmetry on the open channels of dipositronium has
been studied, and the symmetry-adapted lowest open channel of each quantum
state has been identified. Based on this study, the existence of two more 0^+
bound states has been theoretically confirmed, and a 0^+ narrow resonance has
been predicted. A variational calculation has been performed to evaluate the
critical strength of the repulsive interaction . Two 0^- states are found to
have their critical strengths very close to 1, they are considered as
candidates of new narrow resonances or loosely bound states .Comment: 10 pages, 0 figure
Time-dependent correlation function of the Jordan-Wigner operator as a Fredholm determinant
We calculate a correlation function of the Jordan-Wigner operator in a class
of free-fermion models formulated on an infinite one-dimensional lattice. We
represent this function in terms of the determinant of an integrable Fredholm
operator, convenient for analytic and numerical investigations. By using Wick's
theorem, we avoid the form-factor summation customarily used in literature for
treating similar problems.Comment: references added, introduction and conclusion modified, version
accepted for publication in J. Stat. Mec
A gravitationally lensed quasar discovered in OGLE
Indexación: Scopus; Web of Science.We report the discovery of a new gravitationally lensed quasar (double) from the Optical Gravitational Lensing Experiment (OGLE) identified inside the ~670deg2 area encompassing the Magellanic Clouds. The source was selected as one of ~60 'red W1-W2' mid-infrared objects from WISE and having a significant amount of variability in OGLE for both two (or more) nearby sources. This is the first detection of a gravitational lens, where the discovery is made 'the other way around', meaning we first measured the time delay between the two lensed quasar images of -132 < tAB < -76 d (90 per cent CL), with the median tAB ~-102 d (in the observer frame), and where the fainter image B lags image A. The system consists of the two quasar images separated by 1.5 arcsec on the sky, with I ~20.0mag and I ~19.6mag, respectively, and a lensing galaxy that becomes detectable as I ~21.5 mag source, 1.0 arcsec from image A, after subtracting the two lensed images. Both quasar images show clear AGN broad emission lines at z=2.16 in the New Technology Telescope spectra. The spectral energy distribution (SED) fitting with the fixed source redshift provided the estimate of the lensing galaxy redshift of z ~0.9 ± 0.2 (90 per cent CL), while its type is more likely to be elliptical (the SED-inferred and lens-model stellar mass is more likely present in ellipticals) than spiral (preferred redshift by the lens model). © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.https://academic.oup.com/mnras/article/476/1/663/483368
Az Istállós-kői-barlang ásatásának folytatása és a Bükki Aurignaci kérdése = Continuation of Excavating Istállós-kő Cave and Problem of Bükk Aurignacian
A T046892 OTKA pályázat kutatási programja keretében 2004-2005-ben sikerült tovább folytatni az Istállós-kői-barlang, 2005-2006-ban pedig a Herman Otto-barlang revíziós ásatását elvégezni. A program keretében lehetőség nyílt a teljes Bükki-Aurignacien kultúra techno-tipológiai és komplex rétegtani-őskörnyezettani, kronológiai és paleoetnológiai feldolgozására. Szerencsés módon William Davies (University of Southampton) és Marcel Otte (Universite de Liege) C14 programjával együttműködve, több új radiometrikus kormeghatározást elvégezni a Bükki-Aurignacien kultúrával kapcsolatban. Így sor került a különleges jelentőségű Miskolc-Tapolcai-kőfülke Aurignacien koponyaleletének C14 kormeghatározására is. Az eredményeket több konferencián és publikációban mutattuk be. | The number T46892 research program funded by the OTKA, included further excavations and revisions of two main sites: the Istallós-kő (2004-2005) and the Otto Herman Cave (2005-2006). The detailed research program on the Aurignacien Culture in the Bükk Mountains, involved processing all the available data; such as the techno-tipological and the complex stratigraphical-paleoenvironmental, the chronological and the paleoethnological. Working closely with other research programs led by William Davies (University of Southampton) and Marcel Otte (Universite de Liege) we were able to perform many new C14 radiometric dating. Among others, the extremely significant one was done on the occipital bone found in Miskolc-Tapolca's Rockshelter. We have presented the results and conclusions in many conferences and in publications
The hyperfine transition in light muonic atoms of odd Z
The hyperfine (hf) transition rates for muonic atoms have been re-measured
for select light nuclei, using neutron detectors to evaluate the time
dependence of muon capture. For F = 5.6 (2)
s for the hf transition rate, a value which is considerably more
accurate than previous measurements. Results are also reported for Na, Al, P,
Cl, and K; that result for P is the first positive identification.Comment: 12 pages including 5 tables and 4 figures, RevTex, submitted to Phys.
Rev.
Domain wall partition functions and KP
We observe that the partition function of the six vertex model on a finite
square lattice with domain wall boundary conditions is (a restriction of) a KP
tau function and express it as an expectation value of charged free fermions
(up to an overall normalization).Comment: 16 pages, LaTeX2
Combinatorics of generalized Bethe equations
A generalization of the Bethe ansatz equations is studied, where a scalar
two-particle S-matrix has several zeroes and poles in the complex plane, as
opposed to the ordinary single pole/zero case. For the repulsive case (no
complex roots), the main result is the enumeration of all distinct solutions to
the Bethe equations in terms of the Fuss-Catalan numbers. Two new combinatorial
interpretations of the Fuss-Catalan and related numbers are obtained. On the
one hand, they count regular orbits of the permutation group in certain factor
modules over Z^M, and on the other hand, they count integer points in certain
M-dimensional polytopes
SDWFS-MT-1: A Self-Obscured Luminous Supernova at z~0.2
We report the discovery of a six-month-long mid-infrared transient,
SDWFS-MT-1 (aka SN 2007va), in the Spitzer Deep, Wide-Field Survey of the NOAO
Deep Wide-Field Survey Bootes field. The transient, located in a z=0.19 low
luminosity (M_[4.5]~-18.6 mag, L/L_MilkyWay~0.01) metal-poor (12+log(O/H)~7.8)
irregular galaxy, peaked at a mid-infrared absolute magnitude of M_[4.5]~-24.2
in the 4.5 micron Spitzer/IRAC band and emitted a total energy of at least
10^51 ergs. The optical emission was likely fainter than the mid-infrared,
although our constraints on the optical emission are poor because the transient
peaked when the source was "behind" the Sun. The Spitzer data are consistent
with emission by a modified black body with a temperature of ~1350 K. We rule
out a number of scenarios for the origin of the transient such as a Galactic
star, AGN activity, GRB, tidal disruption of a star by a black hole and
gravitational lensing. The most plausible scenario is a supernova exploding
inside a massive, optically thick circumstellar medium, composed of multiple
shells of previously ejected material. If the proposed scenario is correct,
then a significant fraction (~10%) of the most luminous supernova may be
self-enshrouded by dust not only before but also after the supernova occurs.
The spectral energy distribution of the progenitor of such a supernova would be
a slightly cooler version of eta Carina, peaking at 20-30 microns.Comment: 26 pages, 5 figures, 1 table, accepted for publication in Ap
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