721 research outputs found
Reflection Amplitudes of ADE Toda Theories and Thermodynamic Bethe Ansatz
We study the ultraviolet asymptotics in affine Toda theories. These models
are considered as perturbed non-affine Toda theories. We calculate the
reflection amplitudes, which relate different exponential fields with the same
quantum numbers. Using these amplitudes we derive the quantization condition
for the vacuum wave function, describing zero-mode dynamics, and calculate the
UV asymptotics of the effective central charge. These asymptotics are in a good
agreement with thermodynamic Bethe ansatz results.Comment: 20 pages, 2 ps figures, LaTeX 2e. We added the last section,
"Concluding Remarks", in which the new result for the one point function <
\exp a\cdot\phi > in ADE affine Toda theories is given explicitly. Version to
appear in Nucl. Phys.
Measurement and PC-SAFT modeling of solid-liquid equilibrium of deep eutectic solvents of quaternary ammonium chlorides and carboxylic acids
In this study the solid-liquid equilibria (SLE) of 15 binary mixtures composed of one of three different symmetrical quaternary ammonium chlorides and one of five different fatty acids were measured. The experimental data obtained showed extreme negative deviations to ideality causing large melting-temperature depressions (up to 300 K) that are characteristic for deep eutectic systems. The experimental data revealed that cross-interactions between quaternary ammonium salt and fatty acid increase with increasing alkyl chain length of the quaternary ammonium chloride and with increasing chain length of the carboxylic acid. The pronounced decrease of melting temperatures in these deep eutectic systems is mainly caused by strong hydrogen-bonding interactions, and thermodynamic modeling required an approach that takes hydrogen bonding into account. Thus, the measured phase diagrams were modeled with perturbed-chain statistical associating fluid theory based on the classical molecular homonuclear approach. The model showed very good agreement with the experimental data using a semi-predictive modeling approach, in which binary interaction parameters between quaternary ammonium chloride and carboxylic acid correlated with chain length of the components. This supports the experimental findings on the phase behavior and interactions present in these systems and it allows estimating eutectic points of such highly non-ideal mixtures.This work was developed in the scope of the project CICECO e
Aveiro Institute of Materials, POCI-01-0145-FEDER-007679
(Ref. FCT UID/CTM/50011/2013) and LSRE-LCM, POCI-01-0145-
FEDER-006984jUID/EQU/50020/2013, financed by national funds
through the FCT/MEC and when appropriate co-financed by FEDER
under the PT2020 Partnership Agreement. M.A.R.M acknowledges
FCT for her PhD grant (SFRH/BD/87084/2012). FCT is also
acknowledged for funding the project DeepBiorefinery (PTDC/AGRTEC/
1191/2014). P.V.A.P., G.J.M., M.D.H. and E.A.C.B thank the national
funding agencies CNPq (National Council for Scientific and
Technological Development) (305870/2014-9, 309780/2014,
406856/2013-3), FAPESP (Research Support Foundation of the State
of S~ao Paulo) (2014/21252-0, 2016/08566-1), FAEPEX/UNICAMP
(Fund for Research, Teaching, and Extension) (0125/16) and
CAPES (Coordination of Improvement of Higher Level Personnel)
for financial support and scholarships. E.A.C thanks
Erasmusþ program of the European Union for co-funding.info:eu-repo/semantics/publishedVersio
Dissociation cross sections of ground-state and excited charmonia with light mesons in the quark model
We present numerical results for the dissociation cross sections of
ground-state, orbitally- and radially-excited charmonia in collisions with
light mesons. Our results are derived using the nonrelativistic quark model, so
all parameters are determined by fits to the experimental meson spectrum.
Examples of dissociation into both exclusive and inclusive final states are
considered. The dissociation cross sections of several C=(+) charmonia may be
of considerable importance for the study of heavy ion collisions, since these
states are expected to be produced more copiously than the J/psi. The relative
importance of the productions of ground-state and orbitally-excited charmed
mesons in a pion-charmonium collision is demonstrated through the -dependent charmonium dissociation cross sections.Comment: 9 pages, 8 figure
Further evidence for a variable fine-structure constant from Keck/HIRES QSO absorption spectra
[Abridged] We previously presented evidence for a varying fine-structure
constant, alpha, in two independent samples of Keck/HIRES QSO spectra. Here we
present a detailed many-multiplet analysis of a third Keck/HIRES sample
containing 78 absorption systems. We also re-analyse the previous samples,
providing a total of 128 absorption systems over the redshift range
0.2<z_abs<3.7. All three samples separately yield consistent, significant
values of da/a. The analyses of low- and high-z systems rely on different
ions/transitions with very different dependencies on alpha, yet they also give
consistent results. We identify additional random errors in 22 high-z systems
characterized by transitions with a large dynamic range in apparent optical
depth. Increasing the statistical errors on da/a for these systems gives our
fiducial result, a weighted mean da/a=(-0.543+/-0.116)x10^-5, representing
4.7-sigma evidence for a smaller weighted mean alpha in the absorption clouds.
Assuming that da/a=0 at z_abs=0, the data marginally prefer a linear increase
in alpha with time: dota/a=(6.40+/-1.35)x10^-16 yr^-1. The two-point
correlation function for alpha is consistent with zero over 0.2-13 Gpc comoving
scales and the angular distribution of da/a shows no significant dipolar
anisotropy. We therefore have no evidence for spatial variations in da/a. We
extend our previous searches for possible systematic errors, identifying
atmospheric dispersion and isotopic structure effects as potentially the most
significant. However, overall, known systematic errors do not explain the
results. Future many-multiplet analyses of QSO spectra from different
telescopes and spectrographs will provide a now crucial check on our Keck/HIRES
results.Comment: 31 pages, 25 figures (29 EPS files), 8 tables. Accepted by MNRAS.
Colour versions of Figs. 6, 8 & 10 and text version of Table 3 available at
http://www.ast.cam.ac.uk/~mim/pub.htm
Black hole solutions in F(R) gravity with conformal anomaly
In this paper, we consider theory instead of Einstein gravity
with conformal anomaly and look for its analytical solutions. Depending on the
free parameters, one may obtain both uncharged and charged solutions for some
classes of models. Calculation of Kretschmann scalar shows that there is
a singularity located at , which the geometry of uncharged (charged)
solution is corresponding to the Schwarzschild (Reissner-Nordstr\"om)
singularity. Further, we discuss the viability of our models in details. We
show that these models can be stable depending on their parameters and in
different epoches of the universe.Comment: 12 pages, one figur
- …