Article
Physics, Particles & Fields
Federico Carta, Alessandro Mininno, Nicole Righi, Alexander Westphal
Summary: This study proposes a combined mechanism for winding inflation and de Sitter uplifts, using the Gopakumar-Vafa invariants of Calabi-Yau threefolds. A database is created to demonstrate the existence of Calabi-Yau threefolds with the prescribed hierarchy of invariants. Redundancies in the CICY list are also identified as a side result.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Francesc Cunillera, Antonio Padilla
Summary: Dark energy in string theory, taking the form of quintessence field in slow roll, may signal the end of the universe as we know it, possibly through decompactification. A tower of heavy states descending as quintessence rolls may trigger an apocalyptic phase transition in the cosmological dynamics after a certain time, demonstrating a breakdown in the dynamics as the tower becomes light.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Thomas W. Grimm, Chongchuo Li
Summary: The study focuses on the backreaction effect of a large axion field on its saxion partner in the same N = 1 multiplet, highlighting the remarkable pattern engraved by the boundary structure in scalar potentials.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Heliudson Bernardo, Paul-Robert Chouha, Guilherme Franzmann
Summary: The study focuses on the matter-coupled equations of motion for cosmological NS massless fields, specifically the Kalb-Ramond two-form field and its source in an O(d, d) duality invariant approach. Solutions for both vacuum and matter cases are found, and the non-isotropic nature of the two-form field under the duality invariant framework is discussed.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Heliudson Bernardo, Jan Chojnacki, Vincent Comeau
Summary: We investigate the non-linear stability of fixed-point solutions to the alpha'-exact equations in O(d,d) invariant cosmology, considering both with and without matter perturbations. The previous non-linear analysis in literature is reviewed and its compatibility with known linear perturbation results is demonstrated. We also discuss the formal aspects of cosmological perturbations in duality invariant cosmology and establish the existence of time-reparameterization invariant variables for perturbations.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Mitsuhiro Kato, Kanji Nishii, Toshifumi Noumi, Toshiaki Takeuchi, Siyi Zhou
Summary: In de Sitter space, semiclassical spiky strings and the corresponding Regge trajectories are studied, showing that each trajectory has a maximum spin due to de Sitter acceleration similar to the folded string. This leads to the question of how to maintain mild high-energy string scattering, which is familiar in flat space and anti-de Sitter space. Analysis suggests that achieving infinitely many higher spin states requires considering infinitely many Regge trajectories with increasing folding numbers.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Max Brinkmann, Michele Cicoli, Giuseppe Dibitetto, Francisco G. Pedro
Summary: This study investigates the consistency of embedding quintessence models within gravity coupled to two scalar fields in string theory. The results show difficulties in finding trajectories compatible with cosmological parameters, but universal trajectories may be compatible if the starting point is a phase of kinetic domination. However, justifying the choice of initial conditions remains challenging.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
David Andriot, Ludwig Horer, George Tringas
Summary: In this paper, we characterize negative scalar potentials, V < 0, in d-dimensional effective theories of quantum gravity through the Anti-Trans-Planckian Censorship Conjecture (ATCC) inspired by a refined version of the TCC. The ATCC is based on the fact that sub-Planckian length modes violate the validity of the effective theory in a contracting universe. In the asymptotics of field space, we find that -V'/V >= c(0) when V' >= 0. We also derive a new asymptotic condition, V''/V >= c(0)(2), and infer the existence of a scalar with mass satisfying m(2)l(2) less than or similar to -2 in anti-de Sitter solutions.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Heliudson Bernardo, Robert Brandenberger
Summary: This study investigates the cosmology obtained using scalar fields with negative potential energy, and applies the covariant entropy bound and distance conjecture to derive constraints on the potential. The findings suggest that the relative slope of the potential is bounded from below by a constant in Planck units for slow Ekpyrotic contraction.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Jerome Quintin, Heliudson Bernardo, Guilherme Franzmann
Summary: This paper revisits the cosmology of the fully alpha'-corrected duality-invariant action for the Neveu-Schwarz sector of string theory, with a special emphasis on its coupling to matter sources. The role of duality covariant pressure and dilatonic charge of the matter sector is explored in various contexts, from the low-curvature regime to non-perturbative solutions in alpha'.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Michele Cicoli, Veronica Guidetti, Nicole Righi, Alexander Westphal
Summary: This paper reassesses the possibility of generating fuzzy dark matter candidates in string theory through a detailed study of the masses and decay constants of different axion fields. It is found that obtaining a significant contribution to the observed dark matter abundance without tuning the axion initial misalignment angle is not a generic feature of 4D string models. The study identifies C-4-axions, C-2-axions, and thraxions as the best candidates to realize fuzzy dark matter in string theory.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
George Gkountoumis, Chris Hull, Koen Stemerdink, Stefan Vandoren
Summary: We study freely acting orbifolds of type IIB string theory on T-5 that spontaneously break supersymmetry. We construct modular invariant partition functions and provide examples of both symmetric and asymmetric orbifolds. The orbifolds we consider arise at special points in the moduli space of string theory compactifications with a duality twist, and they generate gauged supergravities with positive definite classical potentials in five dimensions.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Borna Salehian, Hong-Yi Zhang, Mustafa A. Amin, David Kaiser, Mohammad Hossein Namjoo
Summary: This paper systematically derives the SP equations and relativistic corrections from the nonlinear and fully relativistic KGE equations in an expanding universe, providing insights into deviations and applicability beyond the SP system. The method presented simplifies the analysis of scalar dark matter dynamics and accurately captures deviations from the SP system towards the full KGE case, particularly in calculating the mass-radius relationship of solitons.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
So Okano, Tomohiro Fujita
Summary: This study numerically investigates the occurrence of Schwinger preheating in different inflation models and finds that it only occurs when there is a sufficiently large coupling between the inflaton and photons in the Starobinsky inflation model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Ananya Tapadar, Sougata Ganguly, Sourov Roy
Summary: In this paper, the non-adiabatic evolution of dark sector is studied in the framework of a U(1)(L mu)-( L tau )circle times U(1)(x) extension of the standard model. The connection between the visible and dark sectors is established through a portal coupling. The temperature evolution and various non-equilibrium stages of the dark sector are analyzed. Constraints on the model parameters from laboratory and astrophysical searches are investigated. The parameter space for the non-adiabatic evolution of the dark sector is significantly constrained for certain values of mass and coupling, while other constraints depend on the mass ratio.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
S. AbdusSalam, S. Abel, M. Cicoli, F. Quevedo, P. Shukla
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Physics, Particles & Fields
Igor Broeckel, Michele Cicoli, Anshuman Maharana, Kajal Singh, Kuver Sinha
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Physics, Particles & Fields
Rouzbeh Allahverdi, Igor Brockel, Michele Cicoli, Jacek K. Osinski
Summary: Explicit string models face challenges in realizing inflation and low-energy supersymmetry, but early matter domination driven by string moduli can potentially alter dark matter abundance and imply superheavy neutralino dark matter with mass around 10(10)-10(11) GeV, which may help explain recent ultra-high-energy neutrino detections by IceCube and ANITA through dark matter decay.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Zainab Nazari, Michele Cicoli, Katy Clough, Francesco Muia
Summary: This study investigates the dynamics of pseudotopological objects called oscillons for a class of models inspired by axion-monodromy using numerical relativity simulations. It contrasts the effects of adding self-interactions with or without gravitational support, mapping out regions of parameter space where initial conditions collapse to black holes or remain pseudo-stable or disperse.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Correction
Physics, Particles & Fields
Igor Broeckel, Michele Cicoli, Anshuman Maharana, Kajal Singh, Kuver Sinha
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
M. Cicoli, F. Quevedo, R. Savelli, A. Schachner, R. Valandro
Summary: Extracting reliable low-energy information from string compactifications requires understanding the UV sensitivity of the corresponding effective field theories. This study focuses on the moduli dependence of perturbative corrections to the 4D scalar potential in type IIB Calabi-Yau orientifold compactifications. Two strategies are employed to infer the dependence of perturbative corrections on both the dilaton and the Calabi-Yau volume. The research also shows that KK reductions on elliptically-fibred Calabi-Yau fourfolds can only generate (alpha')(even) corrections to the 4D scalar potential.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
M. Cicoli, I. Garcia Etxebarria, F. Quevedo, A. Schachner, P. Shukla, R. Valandro
Summary: A new method of embedding the Standard Model quiver into compact Calabi-Yau geometries has been proposed, illustrated by constructing a single dP(5) model. This procedure simplifies the original dP(5) quiver gauge theory to a Left-Right symmetric model, with the potential to further break symmetries to the Standard Model gauge group.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Igor Broeckel, Michele Cicoli, Anshuman Maharana, Kajal Singh, Kuver Sinha
Summary: The paper re-examines the realisation of the QCD axion in string theory, studying the statistics of axion physics in the string landscape. It is found that in type IIB flux compactifications, the closed string axions have a decay constant and mass spectrum distribution that features a logarithmic pattern, rather than a power-law distribution.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Correction
Physics, Particles & Fields
Igor Broeckel, Michele Cicoli, Anshuman Maharana, Kajal Singh, Kuver Sinha
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Michele Cicoli, Veronica Guidetti, Francesco Muia, Francisco G. Pedro, Gian Paolo Vacca
Summary: In type IIB fibre inflation models, it has been argued that the instability caused by tachyonic isocurvature perturbations is unphysical due to the use of ill-defined entropy variables. By employing the correct relative entropy perturbation, it has been demonstrated that axionic isocurvature perturbations decay during inflation and the dynamics becomes essentially single-field.
CLASSICAL AND QUANTUM GRAVITY
(2022)
Article
Physics, Particles & Fields
Michele Cicoli, Matteo Licheri, Ratul Mahanta, Anshuman Maharana
Summary: In this article, a novel method is presented to obtain type IIB flux vacua with flat directions. This method has been applied to toroidal and Calabi-Yau compactifications and explicit solutions have been obtained and classified. Promising starting points have been found in Calabi-Yaus for constructing dS structures.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Michele Cicoli, Veronica Guidetti, Francesco Muia, Francisco G. Pedro, Gian Paolo Vacca
Summary: We discuss the usefulness and theoretical consistency of different entropy variables used in the literature to describe isocurvature perturbations in multifield inflationary models. We clarify which is the proper entropy variable to be used to compare with observational constraints. We find that commonly used variables can lead to wrong results or unphysical destabilisation effects for cases with light kinetically coupled spectator fields.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Physics, Particles & Fields
Michele Cicoli, Matteo Licheri, Anshuman Maharana, Kajal Singh, Kuver Sinha
Summary: In this study, the joint distribution of the gravitino mass and the cosmological constant in KKLT and LVS models with anti-D3 brane uplifting is obtained using the nilpotent goldstino formalism. Moduli stabilisation of both complex structure and Kahler moduli is considered, and the distributions of the flux superpotential, string coupling, and hierarchies of warped throats are taken as key inputs. The results show that, in the limit of zero cosmological constant, both KKLT and LVS models have distributions that favor lower scales of supersymmetry breaking.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Max Brinkmann, Michele Cicoli, Giuseppe Dibitetto, Francisco G. Pedro
Summary: This study investigates the consistency of embedding quintessence models within gravity coupled to two scalar fields in string theory. The results show difficulties in finding trajectories compatible with cosmological parameters, but universal trajectories may be compatible if the starting point is a phase of kinetic domination. However, justifying the choice of initial conditions remains challenging.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Michele Cicoli, Matteo Licheri, Ratul Mahanta, Evan McDonough, Francisco G. Pedro, Marco Scalisi
Summary: Early Dark Energy (EDE) is a potential model for resolving the Hubble Tension and is informed by Cosmic Microwave Background data. It can be realized in type IIB string theory with the EDE field identified as a C-4 or C-2 axion, and with the moduli stabilization achieved in either KKLT or the Large Volume Scenario. Natural hierarchy between the EDE energy scale and other fields can be achieved in a controlled effective field theory. The most promising EDE candidates are the C-2 axions in LVS with 3 non-perturbative corrections to the superpotential generated by gaugino condensation on D7-branes with non-zero world-volume fluxes.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)