296 citations · 521 across the 25 of their papers we have counts for
25 papers
Primordial Asymmetries, Primordial Equation of State & Primordial Black Holes
Maël Gonin, Julien Froustey, Albert Escrivà +3
We study the thermal history of the primordial Universe in the presence of non-zero lepton and baryon asymmetries. Considering different scenarios, we determine the equation of sta…
What could an emerging Big Bang Nucleosynthesis discrepancy be hinting at?
Vivian Poulin, Julien Froustey, Cyril Pitrou +1
The latest measurement of the primordial deuterium abundance is in tension with several state-of-the-art predictions of standard Big Bang nucleosynthesis (BBN), when usin…
Neutrino helicity oscillations in astrophysical environments: A many-body approach
Yiheng Xu, Julien Froustey, George M. Fuller +2
Neutrino rest mass enables left-handed states to "flip" to right-handed states and vice versa. In-medium effects can enhance the probability for such spin-flip. We demonstrate that…
Neutrino transport and flavor instabilities in a post-merger disk
Erick Urquilla, Swapnil Shankar, Debraj Kundu +6
Neutron star mergers are multimessenger sources whose dynamics and signals depend critically on neutrinos and their flavor transformations. We investigate whether fast and collisio…
Impact of non-standard neutrino-electron interactions on Big Bang Nucleosynthesis
Julien Froustey, Stefano Gariazzo, Jaume Moncho +2
Neutrino non-standard interactions (NSI) with electrons, predicted in many extended theoretical models of particle physics, are known to alter the picture of neutrino decoupling fr…
Neutrino flavor instabilities in neutron star mergers with moment transport: Slow, fast, and collisional modes
Julien Froustey, Francois Foucart, Christian Hall +5
Determining where, when, and how neutrino flavor oscillations must be included in large-scale simulations of hot and dense astrophysical environments is an enduring challenge that…
Fifty shades of grayness: parametrizations of spectral distortions and applications in cosmology
Gabriela Barenboim, Julien Froustey, Cyril Pitrou +1
Thermal distribution functions can only be of the Fermi-Dirac or Bose-Einstein types, whereas distorted spectra encompass any possible deviations from these shapes. It is fruitful…
Return of the Lepton Number: Sterile Neutrino Dark Matter Production and the Revival of the Shi-Fuller Mechanism
Cannon M. Vogel, Helena García Escudero, Julien Froustey +1
We explore resonant production of sterile neutrino dark matter via the Shi-Fuller (SF) mechanism, revisiting its cosmological viability in light of recent results demonstrating tha…
Predicting the outcome of collisional neutrino flavor conversion
Julien Froustey
Collisional flavor instabilities, driven by differing neutrino and antineutrino reaction rates, are expected to occur in dense astrophysical environments like supernovae and neutro…
Primordial neutrinos fade to gray: constraints from cosmological observables
Gabriela Barenboim, Julien Froustey, Cyril Pitrou +1
We investigate the effect of potentially large distortions of the relic neutrino spectra on cosmological observables. To that end, we consider a phenomenological model of "gray" sp…
Neutrino Theory in the Precision Era
Asmaa Abada, Gabriela Barenboim, Toni Bertólez-Martínez +76
This document summarises discussions on future directions in theoretical neutrino physics, which are the outcome of a neutrino theory workshop held at CERN in February 2025. The st…
Advection Algorithms for Quantum Neutrino Moment Transport
Evan Grohs, Sherwood Richers, Julien Froustey +3
Neutrino transport in compact objects is an inherently challenging multi-dimensional problem. This difficulty is compounded if one includes flavor transformation -- an intrinsicall…
Non-conservation of Lepton Numbers in the Neutrino Sector Could Change the Prospects for Core Collapse Supernova Explosions
Anna M. Suliga, Patrick Chi-Kit Cheong, Julien Froustey +5
We show that interactions violating the conservation of lepton numbers in the neutrino sector could significantly alter the standard low entropy picture for the pre-supernova colla…
Quantum Closures for Neutrino Moment Transport
James P. Kneller, Julien Froustey, Evan B. Grohs +3
A computationally efficient method for calculating the transport of neutrino flavor in simulations is to use angular moments of the neutrino one-body reduced density matrix, i.e.,…
Quantum maximum entropy closure for small flavor coherence
Julien Froustey, James P. Kneller, Gail C. McLaughlin
Quantum angular moment transport schemes are an important avenue toward describing neutrino flavor mixing phenomena in dense astrophysical environments such as supernovae and mergi…
Asymptotic-state prediction for fast flavor transformation in neutron star mergers
Sherwood Richers, Julien Froustey, Somdutta Ghosh +2
Neutrino flavor instabilities appear to be omnipresent in dense astrophysical environments, thus presenting a challenge to large-scale simulations of core-collapse supernovae and n…
Constraints on primordial lepton asymmetries with full neutrino transport
Julien Froustey, Cyril Pitrou
Primordial neutrino-antineutrino asymmetries can be constrained through big-bang nucleosynthesis (BBN) relic abundances and cosmic microwave background (CMB) anisotropies, both obs…
Neutrino flavor transformation with moments: application to fast flavor instabilities in neutron star mergers
Julien Froustey, Sherwood Richers, Evan Grohs +4
Neutrino evolution, of great importance in environments such as neutron star mergers (NSMs) because of their impact on explosive nucleosynthesis, is still poorly understood due to…
Neutrino fast flavor oscillations with moments: linear stability analysis and application to neutron star mergers
Julien Froustey, Sherwood Richers, Evan Grohs +4
Providing an accurate modeling of neutrino physics in dense astrophysical environments such as binary neutron star mergers presents a challenge for hydrodynamic simulations. Nevert…
Two-Moment Neutrino Flavor Transformation with applications to the Fast Flavor Instability in Neutron Star Mergers
Evan Grohs, Sherwood Richers, Sean M. Couch +4
Multi-messenger astrophysics has produced a wealth of data with much more to come in the future. This enormous data set will reveal new insights into the physics of core collapse s…
The Universe at the MeV era: neutrino evolution and cosmological observables
Julien Froustey
Neutrino physics in the early Universe is key to our understanding of later cosmological stages, such as primordial nucleosynthesis (BBN) or the formation of large-scale structures…
Precision calculation of neutrino evolution in the early Universe
Julien Froustey
In the primordial Universe, neutrino decoupling occurs only slightly before electron-positron annihilations. This leads notably to an increased neutrino energy density compared to…
Primordial neutrino asymmetry evolution with full mean-field effects and collisions
Julien Froustey, Cyril Pitrou
Neutrino oscillations and mean-field effects considerably enrich the phenomenology of neutrino evolution in the early Universe. Taking into account these effects, most notably the…
Neutrino decoupling including flavour oscillations and primordial nucleosynthesis
Julien Froustey, Cyril Pitrou, Maria Cristina Volpe
We revisit the decoupling of neutrinos in the early universe with flavour oscillations. We rederive the quantum kinetic equations which determine the neutrino evolution based on a…