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Records |
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Author |
Mata, R.; Cros, A.; Gimeno, B.; Raboso, D. |
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Title |
Secondary electron emission yield in thick dielectric materials: a comparison between Kelvin probe and capacitive methods |
Type |
Journal Article |
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Year |
2024 |
Publication |
Journal of Physics D |
Abbreviated Journal |
J. Phys. D |
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Volume |
57 |
Issue |
40 |
Pages |
405302 - 9pp |
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Keywords |
dielectrics; secondary electron emission yield; Multipactor in space devices |
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Abstract |
The recent high demand of secondary electron emission yield (SEY) measurements in dielectric materials from space industry has driven SEY laboratories to improve their facilities and measurement techniques. SEY determination by the common capacitive method, also known as pulsed method, is well accepted and has given satisfactory results in most cases. Nevertheless, the samples under study must be prepared according to the experimental limitations of the technique, i.e. they should be manufactured separated from the devices representing faithfully the surface state of the own device and be as thin as possible. A method based on the Kelvin probe (KP) is proposed here to obtain the SEY characteristics of electrically floating Platinum, Kapton and Teflon placed over dielectric spacers with thicknesses ranging from 1.6 to 12.1 mm. The results are compared with those of the capacitive method and indicate that KP SEY curves are less sensitive to spacer thickness. An explanation based on the literature is also given. In all, we have established that KP is better suited for the analysis of dielectric samples thicker than 3 mm. |
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Address |
[Mata, R.; Gimeno, B.] Ciudad Politecn Innovac, Val Space Consortium, Edificio 8G,Acceso B,Planta B, Valencia 46022, Spain, Email: rafael.mata@uv.es |
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IOP Publishing Ltd |
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English |
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0022-3727 |
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Notes |
WOS:001269188200001 |
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no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6203 |
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Permanent link to this record |
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Author |
Masud, M.; Bishai, M.; Mehta, P. |
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Title |
Extricating New Physics Scenarios at DUNE with Higher Energy Beams |
Type |
Journal Article |
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Year |
2019 |
Publication |
Scientific Reports |
Abbreviated Journal |
Sci Rep |
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Volume |
9 |
Issue |
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Pages |
352 - 9pp |
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Abstract |
The proposed Deep Underground Neutrino Experiment (DUNE) utilizes a wide-band on-axis tunable muon-(anti) neutrino beam with a baseline of 1300 km to search for CP violation with high precision. Given the long baseline, DUNE is also sensitive to effects due to matter induced non-standard neutrino interactions (NSI) which can interfere with the standard three-flavor oscillation paradigm. Hence it is desirable to design strategies to disentangle effects due to NSI from standard oscillations. In this article, we exploit the tunability of the DUNE neutrino beam over a wide-range of energies to devise an experimental strategy for separating oscillation effects due to NSI from the standard three-flavor oscillation scenario. Using chi(2) analysis, we obtain an optimal combination of beam tunes and distribution of run times in neutrino and anti-neutrino modes that would enable DUNE to isolate new physics scenarios from the standard. We can distinguish scenarios at 3 sigma (5 sigma) level for almost all (similar to 50%) values of delta. To the best of our knowledge, our strategy is entirely new and has not been reported elsewhere. |
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Address |
[Masud, Mehedi] Univ Valencia, CSIC, Inst Fis Corpuscular, Astroparticle & High Energy Phys Grp, Parc Cient Paterna,C Catedrat Jose Beltran 2E, E-46980 Valencia, Spain, Email: masud@ific.uv.es; |
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Publisher |
Nature Publishing Group |
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English |
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ISSN |
2045-2322 |
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Conference |
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Notes |
WOS:000456392400033 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3891 |
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Author |
Masud, M.; Roy, S.; Mehta, P. |
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Title |
Correlations and degeneracies among the NSI parameters with tunable beams at DUNE |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
99 |
Issue |
11 |
Pages |
115032 - 19pp |
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Keywords |
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Abstract |
The Deep Underground Neutrino Experiment (DUNE) is a leading experiment in neutrino physics which is presently under construction. DUNE aims to measure the yet unknown parameters in the three flavor oscillation scenario which includes discovery of leptonic CP violation, determination of the mass hierarchy and determination of the octant of theta(23). Additionally, the ancillary goals of DUNE include probing the subdominant effects induced by new physics. A widely studied new physics scenario is that of nonstandard neutrino interactions (NSI) in propagation which impacts the oscillations of neutrinos. We consider some of the essential NSI parameters impacting the oscillation signals at DUNE and explore the space of NSI parameters as well as study their correlations among themselves and with the yet unknown CP violating phase, delta appearing in the standard paradigm. The experiment utilizes a wide band beam and provides us with a unique opportunity to utilize different beam tunes at DUNE. We demonstrate that combining information from different beam tunes (low energy and medium energy) available at DUNE impacts the ability to probe some of these parameters and leads to altering the allowed regions in two-dimensional space of parameters considered. |
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Address |
[Masud, Mehedi] Univ Valencia, CSIC, Astroparticle & High Energy Phys Grp, Inst Fis Corpuscular, Parc Cient Paterna,C Catedratico Jose Beltran, E-46980 Paterna, Valencia, Spain, Email: masud@ific.uv.es; |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000473025600009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4067 |
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Permanent link to this record |
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Author |
Masud, M.; Mehta, P.; Ternes, C.A.; Tortola, M. |
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Title |
Non-standard neutrino oscillations: perspective from unitarity triangles |
Type |
Journal Article |
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Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
05 |
Issue |
5 |
Pages |
171 - 19pp |
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Keywords |
Beyond Standard Model; CP violation; Neutrino Physics |
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Abstract |
We formulate an alternative approach based on unitarity triangles to describe neutrino oscillations in presence of non-standard interactions (NSI). Using perturbation theory, we derive the expression for the oscillation probability in case of NSI and cast it in terms of the three independent parameters of the leptonic unitarity triangle (LUT). The form invariance of the probability expression (even in presence of new physics scenario as long as the mixing matrix is unitary) facilitates a neat geometric view of neutrino oscillations in terms of LUT. We examine the regime of validity of perturbative expansions in the NSI case and make comparisons with approximate expressions existing in literature. We uncover some interesting dependencies on NSI terms while studying the evolution of LUT parameters and the Jarlskog invariant. Interestingly, the geometric approach based on LUT allows us to express the oscillation probabilities for a given pair of neutrino flavours in terms of only three (and not four) degrees of freedom which are related to the geometric properties (sides and angles) of the triangle. Moreover, the LUT parameters are invariant under rephasing transformations and independent of the parameterization adopted. |
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Address |
[Masud, Mehedi] Inst Basic Sci IBS, Ctr Theoret Phys Universe, Daejeon 34126, South Korea, Email: masud@ibs.re.kr; |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1029-8479 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000658364000005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4864 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Mastromarco, M. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
High accuracy, high resolution U-235(n,f) cross section from n_TOF (CERN) from 18 meV to 10 keV |
Type |
Journal Article |
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Year |
2022 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
58 |
Issue |
8 |
Pages |
147 - 13pp |
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Abstract |
The U-235(n,f) cross section was measured in a wide energy range (18 meV-170 keV) at the nTOF facility at CERN, relative to Li-6(n,t) and B-10(n,alpha) standard reactions, with high resolution and accuracy, with a setup based on a stack of six samples and six silicon detectors placed in the neutron beam. In this paper we report on the results in the region between 18 meV and 10 keV neutron energy. A resonance analysis has been performed up to 200 eV, with the code SAMMY. The resulting fission kernels are compared with the ones extracted on the basis of the resonance parameters of the most recent major evaluated data libraries. A comparison of the nTOF data with the evaluated cross sections is also performed from thermal to 10 keV neutron energy for the energy-averaged cross section in energy groups of suitably chosen width. A good agreement, within 0.5%, is found on average between the new results and the latest evaluated data files ENDF/B-VIII.0 and JEFF-3.3, as well as with respect to the broad group average fission cross section established in the framework of the standard working group of IAEA (the so-called reference file). However, some discrepancies, of up to 4%, are still present in some specific energy regions. The new dataset here presented, characterized by a unique combination of high resolution and accuracy, low background and wide energy range, can help to improve the evaluations from the Resolved Resonance Region up to 10 keV, also reducing the uncertainties that affect this region. |
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Address |
[Mastromarco, M.; Colonna, N.; Diacono, D.] Ist Nazl Fis Nucl, Sez Bari, Bari, Italy, Email: amaducci@lns.infn.it |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000840312100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5328 |
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Permanent link to this record |
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Author |
Massimi, C.; Cristallo, S.; Domingo-Pardo, C.; Lederer-Woods, C. |
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Title |
n_TOF: Measurements of Key Reactions of Interest to AGB Stars |
Type |
Journal Article |
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Year |
2022 |
Publication |
Universe |
Abbreviated Journal |
Universe |
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Volume |
8 |
Issue |
2 |
Pages |
100 - 19pp |
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Keywords |
s process; MACS; time of flight |
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Abstract |
In the last 20 years, the neutron time-of-flight facility nTOF at CERN has been providing relevant data for the astrophysical slow neutron capture process (s process). At nTOF, neutron-induced radiative capture (n,gamma) as well as (n,p) and (n,alpha) reaction cross sections are measured as a function of energy, using the time-of-flight method. Improved detection systems, innovative ideas and collaborations with other neutron facilities have lead to a considerable contribution of the n_TOF collaboration to studying the s process in asymptotic giant branch stars. Results have been reported for stable and radioactive samples, i.e.,Mg- 24,Mg-25,Mg-26, Al-26, S-33,Fe- 54,Fe-57, Ni-58,Ni-59,Ni-62,Ni-63, Ge-70,Ge-72,Ge-73, Zr-90,Zr-91,Zr-92,Zr-93,Zr-94,Zr-96, La-139, Ce-140, Pm-147, Sm-151,Gd- 154,Gd-155,Gd-157, Tm-171, Os-186,Os-187,Os-188, Au-197, Tl-203,Tl-204,Pb- 204,Pb-206,Pb-207 and Bi-209 isotopes, while others are being studied or planned to be studied in the near future. In this contribution, we present an overview of the most successful achievements, and an outlook of future challenging measurements, including ongoing detection system developments. |
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Address |
[Massimi, Cristian] Univ Bologna, Dept Phys & Astron, I-40127 Bologna, Italy, Email: cristian.massimi@unibo.it; |
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Thesis |
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Publisher |
Mdpi |
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Language |
English |
Summary Language |
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Conference |
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Notes |
WOS:000762514400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5144 |
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Permanent link to this record |
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Author |
Maso-Ferrando, A.; Sanchis-Gual, N.; Font, J.A.; Olmo, G.J. |
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Title |
Boson stars in Palatini f(R) gravity |
Type |
Journal Article |
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Year |
2021 |
Publication |
Classical and Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
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Volume |
38 |
Issue |
19 |
Pages |
194003 - 25pp |
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Keywords |
boson stars; Palatini formalism; modified gravity |
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Abstract |
We explore equilibrium solutions of spherically symmetric boson stars in the Palatini formulation of f (R) gravity. We account for the modifications introduced in the gravitational sector by using a recently established correspondence between modified gravity with scalar matter and general relativity with modified scalar matter. We focus on the quadratic theory f (R) = R + xi R-2 and compare its solutions with those found in general relativity, exploring both positive and negative values of the coupling parameter xi. As matter source, a complex, massive scalar field with and without self-interaction terms is considered. Our results show that the existence curves of boson stars in Palatini f (R) gravity are fairly similar to those found in general relativity. Major differences are observed for negative values of the coupling parameter which results in a repulsive gravitational component for high enough scalar field density distributions. Adding self-interactions makes the degeneracy between f (R) and general relativity even more pronounced, leaving very little room for observational discrimination between the two theories. |
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Address |
[Maso-Ferrando, Andreu; Olmo, Gonzalo J.] Univ Valencia, Dept Fis Teor, Ctr Mixto Univ Valencia CSIC, Valencia 46100, Spain, Email: andreu.maso@uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0264-9381 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000695280300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4964 |
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Permanent link to this record |
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Author |
Maso-Ferrando, A.; Sanchis-Gual, N.; Font, J.A.; Olmo, G.J. |
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Title |
Birth of baby universes from gravitational collapse in a modified-gravity scenario |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
028 - 19pp |
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Keywords |
modified gravity; Wormholes |
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Abstract |
We consider equilibrium models of spherical boson stars in Palatini f (R) = R + CR2 gravity and study their collapse when perturbed. The Einstein-Klein-Gordon system is solved using a recently established correspondence in an Einstein frame representation. We find that, in that frame, the endpoint is a nonrotating black hole surrounded by a quasi -stationary cloud of scalar field. However, the dynamics in the f (R) frame is dramatically different. The innermost region of the collapsing object exhibits the formation of a finite -size, exponentially-expanding baby universe connected with the outer (parent) universe via a minimal area surface (a throat or umbilical cord). Our simulations indicate that this surface is at all times hidden inside a horizon, causally disconnecting the baby universe from observers above the horizon. The implications of our findings in other areas of gravitational physics are also discussed. |
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Address |
[Maso-Ferrando, Andreu; Olmo, Gonzalo J.] Univ Valencia, Ctr Mixto, CSIC, Dept Fis Teor, Valencia 46100, Spain, Email: andreu.maso@uv.es; |
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Corporate Author |
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Thesis |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001025474200010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5577 |
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Permanent link to this record |
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Author |
Maso-Ferrando, A.; Sanchis-Gual, N.; Font, J.A.; Olmo, G.J. |
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Title |
Numerical evolutions of boson stars in Palatini f(R) gravity |
Type |
Journal Article |
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Year |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
109 |
Issue |
4 |
Pages |
044042 - 14pp |
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Keywords |
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Abstract |
We investigate the time evolution of spherically symmetric boson stars in Palatini f(R) gravity through numerical relativity computations. Employing a novel approach that establishes a correspondence between modified gravity with scalar matter and general relativity with modified scalar matter, we are able to use the techniques of numerical relativity to simulate these systems. Specifically, we focus on the quadratic theory f(R) = R + xi R2 and compare the obtained solutions with those in general relativity, exploring both positive and negative values of the coupling parameter xi. Our findings reveal that boson stars in Palatini f(R) gravity exhibit both stable and unstable evolutions. The latter give rise to three distinct scenarios: migration toward a stable configuration, complete dispersion, and gravitational collapse leading to the formation of a baby universe structure. |
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Address |
[Maso-Ferrando, Andreu; Olmo, Gonzalo J.] Ctr Mixto Univ Valencia, Univ Valencia, Dept Fis Teor, CSIC, Burjassot 46100, Valencia, Spain, Email: andreu.maso@uv.es; |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001186268100006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6035 |
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Permanent link to this record |
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Author |
Martins, A.; da Mota, A.F.; Stanford, C.; Contreras, T.; Martin-Albo, J.; Kish, A.; Escobar, C.O.; Para, A.; Guenette, R. |
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Title |
Simple strategy for the simulation of axially symmetric large-area metasurfaces |
Type |
Journal Article |
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Year |
2024 |
Publication |
Journal of the Optical Society of America B |
Abbreviated Journal |
J. Opt. Soc. Am. B |
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Volume |
41 |
Issue |
5 |
Pages |
1261-1269 |
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Keywords |
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Abstract |
Metalenses are composed of nanostructures for focusing light and have been widely explored in many exciting applications. However, their expanding dimensions pose simulation challenges. We propose a method to simulate metalenses in a timely manner using vectorial wave and ray tracing models. We sample the metalens's radial phase gradient and locally approximate the phase profile by a linear phase response. Each sampling point is modeled as a binary blazed grating, employing the chosen nanostructure, to build a transfer function set. The metalens transmission or reflection is then obtained by applying the corresponding transfer function to the incoming field on the regions surrounding each sampling point. Fourier optics is used to calculate the scattered fields under arbitrary illumination for the vectorial wave method, and a Monte Carlo algorithm is used in the ray tracing formalism. We validated our method against finite -difference time domain simulations at 632 nm, and we were able to simulate metalenses larger than 3000 wavelengths in diameter on a personal computer. |
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Address |
[Martins, Augusto; Guenette, Roxanne] Univ Manchester, Dept Phys, Manchester M13 9PL, England, Email: augusto.martins@york.ac.uk |
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Publisher |
Optica Publishing Group |
Place of Publication |
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Language |
English |
Summary Language |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0740-3224 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001237140900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6140 |
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Permanent link to this record |