370 citations · 1.5k across the 32 of their papers we have counts for
34 papers
Challenges and Opportunities of Gravitational Wave Searches above 10 kHz
Nancy Aggarwal, Odylio D. Aguiar, Diego Blas +34
The first direct measurement of gravitational waves by the LIGO and Virgo collaborations has opened up new avenues to explore our Universe. This white paper outlines the challenges…
4D de Sitter from String Theory via 6D Supergravity
C. P. Burgess, F. Muia, F. Quevedo
We obtain de Sitter (dS) solutions from controlled string-theory constructions. We review how minimal gauged chiral 6D supergravity evades standard dS no-go theorems by having a po…
String Thermodynamics In and Out of Equilibrium: Boltzmann Equations and Random Walks
Andrew R. Frey, Ratul Mahanta, Anshuman Maharana +3
We revisit the study of string theory close to the Hagedorn temperature with the aim towards cosmological applications. We consider interactions of open and closed strings in a gas…
Quantum Transitions, Detailed Balance, Black Holes and Nothingness
Sebastian Cespedes, Senarath de Alwis, Francesco Muia +1
We consider vacuum transitions by bubble nucleation among 4D vacua with different values and signs of the cosmological constant , including both up and down tunnelings. Followin…
Oscillon formation during inflationary preheating with general relativity
Josu C. Aurrekoetxea, Katy Clough, Francesco Muia
We study the non-perturbative evolution of inflationary fluctuations during preheating using fully non-linear general-relativistic field-theory simulations. We choose a single-fiel…
Testing BSM Physics with Gravitational Waves
Francesco Muia, Fernando Quevedo, Andreas Schachner +1
The Cosmic Gravitational Wave Background (CGWB) is an irreducible background of gravitational waves generated by particle exchange in the early Universe plasma. Standard Model part…
Hunt for Light Primordial Black Hole Dark Matter with Ultra-High-Frequency Gravitational Waves
Gabriele Franciolini, Anshuman Maharana, Francesco Muia
Light primordial black holes may comprise a dominant fraction of the dark matter in our Universe. This paper critically assesses whether planned and future gravitational wave detec…
A Faster Growth of Perturbations in an Early Matter Dominated Epoch: Primordial Black Holes and Gravitational Waves
Subinoy Das, Anshuman Maharana, Francesco Muia
We present a scenario for fast growth of cosmological perturbations; , being the scale factor, with for the numerical examples reported in this ar…
GRChombo: An adaptable numerical relativity code for fundamental physics
Tomas Andrade, Llibert Areste Salo, Josu C. Aurrekoetxea +29
GRChombo is an open-source code for performing Numerical Relativity time evolutions, built on top of the publicly available Chombo software for the solution of PDEs. Whilst GRChomb…
Density Perturbations and Primordial Non-Gaussianities in a Closed Universe
Sebastian Cespedes, Senarath de Alwis, Francesco Muia +1
The spatial curvature of the universe is not yet known. Even though at present the Universe is very close to being essentially flat and most signatures of curvature appear to have…
A Fake Instability in String Inflation
Michele Cicoli, Veronica Guidetti, Francesco Muia +2
In type IIB Fibre Inflation models the inflaton is a Kaehler modulus which is kinetically coupled to the corresponding axion. In this setup the curvature of the field space induces…
On the choice of entropy variables in multifield inflation
Michele Cicoli, Veronica Guidetti, Francesco Muia +2
We discuss the usefulness and theoretical consistency of different entropy variables used in the literature to describe isocurvature perturbations in multifield inflationary models…
dNNsolve: an efficient NN-based PDE solver
Veronica Guidetti, Francesco Muia, Yvette Welling +1
Neural Networks (NNs) can be used to solve Ordinary and Partial Differential Equations (ODEs and PDEs) by redefining the question as an optimization problem. The objective function…
Lorentzian Vacuum Transitions: Open or Closed Universes?
Sebastian Cespedes, Senarath P. de Alwis, Francesco Muia +1
We consider the generalisation of quantum tunneling transitions in the WKB approximation to the time-independent functional Schrödinger and Wheeler-DeWitt equations. Following a Lo…
Challenges and Opportunities of Gravitational Wave Searches at MHz to GHz Frequencies
N. Aggarwal, O. D. Aguiar, A. Bauswein +22
The first direct measurement of gravitational waves by the LIGO and Virgo collaborations has opened up new avenues to explore our Universe. This white paper outlines the challenges…
Oscillon collapse to black holes
Zainab Nazari, Michele Cicoli, Katy Clough +1
Using numerical relativity simulations we study the dynamics of pseudo-topological objects called oscillons for a class of models inspired by axion-monodromy. Starting from free fi…
Quantum Transitions Between Minkowski and de Sitter Spacetimes
Senarath P. de Alwis, Francesco Muia, Veronica Pasquarella +1
Quantum transitions among de Sitter and Minkowski spacetimes through bubble nucleation are revisited using the Hamiltonian formalism. We interpret tunnelling probabilities as relat…
The Fate of Dense Scalar Stars
Francesco Muia, Michele Cicoli, Katy Clough +3
Long-lived pseudo-solitonic objects, known as oscillons/oscillatons, which we collectively call real scalar stars, are ubiquitous in early Universe cosmology of scalar field theori…
Cosmology in the presence of multiple light moduli
Bobby S. Acharya, Mansi Dhuria, Diptimoy Ghosh +2
The generic expectation in string/supergravity models is that there are multiple moduli fields with masses of the order of the supersymmetry breaking scale. We study the cosmology…
Hidden Sectors in String Theory: Kinetic Mixings, Fifth Forces and Quintessence
Bobby Samir Acharya, Anshuman Maharana, Francesco Muia
Light moduli fields in string compactifications can have interesting implications for particle physics and cosmology. Fifth force bounds impose stringent constraints on the interac…
De Sitter vs Quintessence in String Theory
Michele Cicoli, Senarath de Alwis, Anshuman Maharana +2
De Sitter solutions have been recently conjectured to be incompatible with quantum gravity. In this paper we critically assess the progress and challenges of different mechanisms t…
Moduli Stars
Sven Krippendorf, Francesco Muia, Fernando Quevedo
We explore the possibility that (Bose-Einstein) condensation of scalar fields from string compactifications can lead to long-lived compact objects. Depending on the type of scalar…
Emerging chromo-natural inflation
Valerie Domcke, Ben Mares, Francesco Muia +1
The shift-symmetric coupling of a pseudo-scalar particle driving inflation to gauge fields provides a unique way of probing cosmic inflation. We show for an SU(2) gauge group how a…
Chiral Global Embedding of Fibre Inflation Models
Michele Cicoli, David Ciupke, Victor A. Diaz +3
We construct explicit examples of fibre inflation models which are globally embedded in type IIB orientifolds with chiral matter on D7-branes and full closed string moduli stabilis…