64 research outputs found
Non-local formulation of ghost-free bigravity theory
We study the ghost-free bimetric theory of Hassan and Rosen, with parameters
such that a flat Minkowski solution exists for both metrics. We show
that, expanding around this solution and eliminating one of the two metrics
with its own equation of motion, the remaining metric is governed by the
Einstein-Hilbert action plus a non-local term proportional to
, where
is the Weyl tensor. The result is valid to quadratic
order in the metric perturbation and to all orders in the derivative expansion.
This example shows, in a simple setting, how such non-local extensions of GR
can emerge from an underlying consistent theory, at the purely classical level.Comment: 16 page
Unitarity and predictiveness in new Higgs inflation
In new Higgs inflation the Higgs kinetic terms are non-minimally coupled to
the Einstein tensor, allowing the Higgs field to play the role of the inflaton.
The new interaction is non-renormalizable, and the model only describes physics
below some cutoff scale. Even if the unknown UV physics does not affect the
tree level inflaton potential significantly, it may still enter at loop level
and modify the running of the Standard Model (SM) parameters. This is analogous
to what happens in the original model for Higgs inflation. A key difference,
though, is that in new Higgs inflation the inflationary predictions are
sensitive to this running. Thus the boundary conditions at the EW scale as well
as the unknown UV completion may leave a signature on the inflationary
parameters. However, this dependence can be evaded if the kinetic terms of the
SM fermions and gauge fields are non-minimally coupled to gravity as well. Our
approach to determine the model's UV dependence and the connection between low
and high scale physics can be used in any particle physics model of inflation.Comment: 21+6 pages, 1 figure; final version accepted by the journal,
improvements of section
Multi-center phase II trial of chemo-radiotherapy with 5-fluorouracil, leucovorin and oxaliplatin in locally advanced esophageal cancer
n/
A standardized model of brain death, donor treatment, and lung transplantation for studies on organ preservation and reconditioning
Ram pressure feeding super-massive black holes
When supermassive black holes at the center of galaxies accrete matter
(usually gas), they give rise to highly energetic phenomena named Active
Galactic Nuclei (AGN). A number of physical processes have been proposed to
account for the funneling of gas towards the galaxy centers to feed the AGN.
There are also several physical processes that can strip gas from a galaxy, and
one of them is ram pressure stripping in galaxy clusters due to the hot and
dense gas filling the space between galaxies. We report the discovery of a
strong connection between severe ram pressure stripping and the presence of AGN
activity. Searching in galaxy clusters at low redshift, we have selected the
most extreme examples of jellyfish galaxies, which are galaxies with long
tentacles of material extending for dozens of kpc beyond the galaxy disk. Using
the MUSE spectrograph on the ESO Very Large Telescope, we find that 6 out of
the 7 galaxies of this sample host a central AGN, and two of them also have
galactic-scale AGN ionization cones. The high incidence of AGN among the most
striking jellyfishes may be due to ram pressure causing gas to flow towards the
center and triggering the AGN activity, or to an enhancement of the stripping
caused by AGN energy injection, or both. Our analysis of the galaxy position
and velocity relative to the cluster strongly supports the first hypothesis,
and puts forward ram pressure as another, yet unforeseen, possible mechanism
for feeding the central supermassive black hole with gas.Comment: published in Nature, Vol.548, Number 7667, pag.30
Multi-center phase II trial of chemo-radiotherapy with 5-fluorouracil, leucovorin and oxaliplatin in locally advanced esophageal cancer
Cosmology with the Laser Interferometer Space Antenna
254 pags:, 44 figs.The Laser Interferometer Space Antenna (LISA) has two scientific objectives of cosmological focus: to probe the expansion rate of the universe, and to understand stochastic gravitational-wave backgrounds and their implications for early universe and particle physics, from the MeV to the Planck scale. However, the range of potential cosmological applications of gravitational-wave observations extends well beyond these two objectives. This publication presents a summary of the state of the art in LISA cosmology, theory and methods, and identifies new opportunities to use gravitational-wave observations by LISA to probe the universe.This work is partly supported by: A.G. Leventis Foundation; Academy of Finland
Grants 328958 and 345070; Alexander S. Onassis Foundation, Scholarship ID: FZO 059-1/2018-2019;
Amaldi Research Center funded by the MIUR program “Dipartimento di Eccellenza” (CUP:
B81I18001170001); ASI Grants No. 2016-24-H.0 and No. 2016-24-H.1-2018; Atracción de Talento
Grant 2019-T1/TIC-15784; Atracción de Talento contract no. 2019-T1/TIC-13177 granted by the
Comunidad de Madrid; Ayuda ‘Beatriz Galindo Senior’ by the Spanish ‘Ministerio de Universidades’,
Grant BG20/00228; Basque Government Grant (IT-979-16); Belgian Francqui Foundation; Centre national
d’Etudes spatiales; Ben Gurion University Kreitman Fellowship, and the Israel Academy of Sciences and
Humanities (IASH) & Council for Higher Education (CHE) Excellence Fellowship Program for
International Postdoctoral Researchers; Centro de Excelencia Severo Ochoa Program SEV-2016-0597;
CERCA program of the Generalitat de Catalunya; Cluster of Excellence “Precision Physics, Fundamental
Interactions, and Structure of Matter” (PRISMA? EXC 2118/1); Comunidad de Madrid, Contrato de
Atracción de Talento 2017-T1/TIC-5520; Czech Science Foundation GAČR, Grant No. 21-16583M; Delta
ITP consortium; Department of Energy under Grant No. DE-SC0008541, DE-SC0009919 and DESC0019195; Deutsche Forschungsgemeinschaft (DFG), Project ID 438947057; Deutsche Forschungsgemeinschaft under Germany’s Excellence Strategy - EXC 2121 Quantum Universe - 390833306; European
Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports (Project
CoGraDS - CZ.02.1.01/0.0/0.0/15 003/0000437); European Union’s H2020 ERC Consolidator Grant
“GRavity from Astrophysical to Microscopic Scales” (Grant No. GRAMS-815673); European Union’s
H2020 ERC, Starting Grant Agreement No. DarkGRA-757480; European Union’s Horizon 2020
programme under the Marie Sklodowska-Curie Grant Agreement 860881 (ITN HIDDeN); European
Union’s Horizon 2020 Research and Innovation Programme Grant No. 796961, “AxiBAU” (K.S.);
European Union’s Horizon 2020 Research Council grant 724659 MassiveCosmo ERC-2016-COG; FCT
through national funds (PTDC/FIS-PAR/31938/2017) and through project “BEYLA – BEYond LAmbda”
with Ref. Number PTDC/FIS-AST/0054/2021; FEDER-Fundo Europeu de Desenvolvimento Regional
through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI-01-0145-
FEDER-031938) and research Grants UIDB/04434/2020 and UIDP/04434/2020; Fondation CFM pour la
Recherche in France; Foundation for Education and European Culture in Greece; French ANR project
MMUniverse (ANR-19-CE31-0020); FRIA Grant No.1.E.070.19F of the Belgian Fund for Research, F.R.
S.-FNRS Fundação para a Ciência e a Tecnologia (FCT) through Contract No. DL 57/2016/CP1364/
CT0001; Fundação para a Ciência e a Tecnologia (FCT) through Grants UIDB/04434/2020, UIDP/04434/
2020, PTDC/FIS-OUT/29048/2017, CERN/FIS-PAR/0037/2019 and “CosmoTests – Cosmological tests of
gravity theories beyond General Relativity” CEECIND/00017/2018; Generalitat Valenciana Grant
PROMETEO/2021/083; Grant No. 758792, project GEODESI; Government of Canada through the
Department of Innovation, Science and Economic Development and Province of Ontario through the
Ministry of Colleges and Universities; Grants-in-Aid for JSPS Overseas Research Fellow (No.
201960698); I?D Grant PID2020-118159GB-C41 of the Spanish Ministry of Science and Innovation;
INFN iniziativa specifica TEONGRAV; Israel Science Foundation (Grant No. 2562/20); Japan Society for
the Promotion of Science (JSPS) KAKENHI Grant Nos. 20H01899 and 20H05853; IFT Centro de
Excelencia Severo Ochoa Grant SEV-2; Kavli Foundation and its founder Fred Kavli; Minerva
Foundation; Ministerio de Ciencia e Innovacion Grant PID2020-113644GB-I00; NASA Grant
80NSSC19K0318; NASA Hubble Fellowship grants No. HST-HF2-51452.001-A awarded by the Space
Telescope Science Institute with NASA contract NAS5-26555; Netherlands Organisation for Science and
Research (NWO) Grant Number 680-91-119; new faculty seed start-up grant of the Indian Institute of
Science, Bangalore, the Core Research Grant CRG/2018/002200 of the Science and Engineering; NSF
Grants PHY-1820675, PHY-2006645 and PHY-2011997; Polish National Science Center Grant 2018/31/D/
ST2/02048; Polish National Agency for Academic Exchange within the Polish Returns Programme under
Agreement PPN/PPO/2020/1/00013/U/00001; Pró-Reitoria de Pesquisa of Universidade Federal de Minas
Gerais (UFMG) under Grant No. 28359; Ramón y Cajal Fellowship contract RYC-2017-23493; Research
Project PGC2018-094773-B-C32 [MINECO-FEDER]; Research Project PGC2018-094773-B-C32
[MINECO-FEDER]; ROMFORSK Grant Project. No. 302640; Royal Society Grant URF/R1/180009
and ERC StG 949572: SHADE; Shota Rustaveli National Science Foundation (SRNSF) of Georgia (Grant
FR/18-1462); Simons Foundation/SFARI 560536; SNSF Ambizione grant; SNSF professorship Grant
(No. 170547); Spanish MINECO’s “Centro de Excelencia Severo Ochoa” Programme Grants SEV-2016-
0597 and PID2019-110058GB-C22; Spanish Ministry MCIU/AEI/FEDER Grant (PGC2018-094626-BC21); Spanish Ministry of Science and Innovation (PID2020-115845GB-I00/AEI/10.13039/
501100011033); Spanish Proyectos de I?D via Grant PGC2018-096646-A-I00; STFC Consolidated
Grant ST/T000732/1; STFC Consolidated Grants ST/P000762/1 and ST/T000791/1; STFC Grant ST/
S000550/1; STFC Grant ST/T000813/1; STFC Grants ST/P000762/1 and ST/T000791/1; STFC under the
research Grant ST/P000258/1; Swiss National Science Foundation (SNSF), project The Non-Gaussian
Universe and Cosmological Symmetries, Project Number: 200020-178787; Swiss National Science
Foundation Professorship Grants No. 170547 and No. 191957; SwissMap National Center for Competence
in Research; “The Dark Universe: A Synergic Multi-messenger Approach” Number 2017X7X85K under
the MIUR program PRIN 2017; UK Space Agency; UKSA Flagship Project, Euclid.Peer reviewe
Renormalization group independence of Cosmological Attractors
The large class of inflationary models known as α- and ξ-attractors gives identical cosmological predictions at tree level (at leading order in inverse power of the number of efolds). Working with the renormalization group improved action, we show that these predictions are robust under quantum corrections. This means that for all the models considered the inflationary parameters (ns,r) are (nearly) independent on the Renormalization Group flow. The result follows once the field dependence of the renormalization scale, fixed by demanding the leading log correction to vanish, satisfies a quite generic condition. In Higgs inflation (which is a particular ξ-attractor) this is indeed the case; in the more general attractor models this is still ensured by the renormalizability of the theory in the effective field theory sense
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