Professor Pedro Ferreira: Publications

SYREN-HALOFIT: A fast, interpretable, high-precision formula for the ΛCDM nonlinear matter power spectrum

Astronomy & Astrophysics EDP Sciences 686 (2024) ARTN A150

Authors:

Deaglan J Bartlett, Benjamin D Wandelt, Matteo Zennaro, Pedro G Ferreira, Harry Desmond

Abstract:

Context.Rapid and accurate evaluation of the nonlinear matter power spectrum,P(k), as a function of cosmological parameters and redshift is of fundamental importance in cosmology. Analytic approximations provide an interpretable solution, yet current approximations are neither fast nor accurate relative to numerical emulators.Aims.We aim to accelerate symbolic approximations toP(k) by removing the requirement to perform integrals, instead using short symbolic expressions to compute all variables of interest. We also wish to make such expressions more accurate by re-optimising the parameters of these models (using a larger number of cosmologies and focussing on cosmological parameters of more interest for present-day studies) and providing correction terms.Methods.We use symbolic regression to obtain simple analytic approximations to the nonlinear scale,kσ, the effective spectral index,neff, and the curvature,C, which are required for theHALOFITmodel. We then re-optimise the coefficients ofHALOFITto fit a wide range of cosmologies and redshifts. We then again exploit symbolic regression to explore the space of analytic expressions to fit the residuals betweenP(k) and the optimised predictions ofHALOFIT. Our results are designed to match the predictions ofEUCLIDEMULATOR2, but we validate our methods againstN-body simulations.Results.We find symbolic expressions forkσ,neffandCwhich have root mean squared fractional errors of 0.8%, 0.2% and 0.3%, respectively, for redshifts below 3 and a wide range of cosmologies. We provide re-optimisedHALOFITparameters, which reduce the root mean squared fractional error (compared toEUCLIDEMULATOR2) from 3% to below 2% for wavenumbersk = 9 × 10−3 − 9 h Mpc−1. We introduceSYREN-HALOFIT(symbolic-regression-enhancedHALOFIT), an extension toHALOFITcontaining a short symbolic correction which improves this error to 1%. Our method is 2350 and 3170 times faster than currentHALOFITandHMCODEimplementations, respectively, and 2680 and 64 times faster thanEUCLIDEMULATOR2 (which requires runningCLASS) and theBACCOemulator. We obtain comparable accuracy toEUCLIDEMULATOR2 and theBACCOemulator when tested onN-body simulations.Conclusions.Our work greatly increases the speed and accuracy of symbolic approximations toP(k), making them significantly faster than their numerical counterparts without loss of accuracy.

The effect of wave dark matter on equal mass black hole mergers

(2024)

Authors:

Josu C Aurrekoetxea, Katy Clough, Jamie Bamber, Pedro G Ferreira

Effect of Wave Dark Matter on Equal Mass Black Hole Mergers

Physical Review Letters American Physical Society (APS) 132:21 (2024) 211401

Authors:

Josu C Aurrekoetxea, Katy Clough, Jamie Bamber, Pedro G Ferreira

Euclid preparation. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples

(2024)

Authors:

Euclid Collaboration, F Dournac, A Blanchard, S Ilić, B Lamine, I Tutusaus, A Amara, S Andreon, N Auricchio, H Aussel, M Baldi, S Bardelli, C Bodendorf, D Bonino, E Branchini, S Brau-Nogue, M Brescia, J Brinchmann, S Camera, V Capobianco, J Carretero, S Casas, M Castellano, S Cavuoti, A Cimatti, G Congedo, CJ Conselice, L Conversi, Y Copin, F Courbin, HM Courtois, A Da Silva, H Degaudenzi, AM Di Giorgio, J Dinis, M Douspis, F Dubath, X Dupac, S Dusini, A Ealet, M Farina, S Farrens, S Ferriol, M Frailis, E Franceschi, S Galeotta, W Gillard, B Gillis, C Giocoli, BR Granett, A Grazian, F Grupp, SVH Haugan, W Holmes, I Hook, F Hormuth, A Hornstrup, P Hudelot, K Jahnke, E Keihänen, S Kermiche, A Kiessling, M Kilbinger, B Kubik, M Kümmel, M Kunz, H Kurki-Suonio, S Ligori, PB Lilje, V Lindholm, I Lloro, D Maino, E Maiorano, O Mansutti, O Marggraf, K Markovic, N Martinet, F Marulli, R Massey, S Maurogordato, E Medinaceli, S Mei, Y Mellier, M Meneghetti, E Merlin, G Meylan, M Moresco, L Moscardini, E Munari, S-M Niemi, JW Nightingale, C Padilla, S Paltani, F Pasian, K Pedersen, WJ Percival, V Pettorino, S Pires, G Polenta, M Poncet, LA Popa, L Pozzetti, F Raison, R Rebolo, A Renzi, J Rhodes, G Riccio, E Romelli, M Roncarelli, E Rossetti, R Saglia, D Sapone, P Schneider, A Secroun, G Seidel, M Seiffert, S Serrano, C Sirignano, G Sirri, L Stanco, C Surace, P Tallada-Crespí, D Tavagnacco, AN Taylor, I Tereno, R Toledo-Moreo, F Torradeflot, EA Valentijn, L Valenziano, T Vassallo, A Veropalumbo, Y Wang, A Zacchei, G Zamorani, J Zoubian, E Zucca, A Biviano, M Bolzonella, A Boucaud, E Bozzo, C Burigana, C Colodro-Conde, G De Lucia, D Di Ferdinando, JA Escartin Vigo, R Farinelli, J Gracia-Carpio, G Mainetti, M Martinelli, N Mauri, C Neissner, Z Sakr, V Scottez, M Tenti, M Viel, M Wiesmann, Y Akrami, V Allevato, S Anselmi, C Baccigalupi, A Balaguera-Antolinez, M Ballardini, L Blot, S Borgani, S Bruton, R Cabanac, A Calabro, G Canas-Herrera, A Cappi, CS Carvalho, G Castignani, T Castro, KC Chambers, S Contarini, AR Cooray, J Coupon, S Davini, B De Caro, S de la Torre, G Desprez, A Díaz-Sánchez, S Di Domizio, H Dole, S Escoffier, AG Ferrari, PG Ferreira, I Ferrero, F Finelli, L Gabarra, K Ganga, J García-Bellido, E Gaztanaga, F Giacomini, G Gozaliasl, H Hildebrandt, A Jimenez Munoz, JJE Kajava, V Kansal, D Karagiannis, CC Kirkpatrick, L Legrand, G Libet, A Loureiro, J Macias-Perez, G Maggio, M Magliocchetti, F Mannucci, R Maoli, CJAP Martins, S Matthew, L Maurin, RB Metcalf, M Migliaccio, P Monaco, C Moretti, G Morgante, S Nadathur, Nicholas A Walton, L Patrizii, A Pezzotta, M Pöntinen, V Popa, C Porciani, D Potter, I Risso, P-F Rocci, M Sahlén, AG Sánchez, JA Schewtschenko, A Schneider, E Sefusatti, M Sereno, J Steinwagner, N Tessore, G Testera, R Teyssier, S Toft, S Tosi, A Troja, M Tucci, J Valiviita, D Vergani, G Verza

Optimal inflationary potentials

Physical Review D American Physical Society 109:8 (2024) 83524

Authors:

Tomás Sousa, Deaglan Bartlett, Harry Desmond, Pedro Ferreira

Abstract:

Inflation is a highly favored theory for the early Universe. It is compatible with current observations of the cosmic microwave background and large scale structure and is a driver in the quest to detect primordial gravitational waves. It is also, given the current quality of the data, highly underdetermined with a large number of candidate implementations. We use a new method in symbolic regression to generate all possible simple scalar field potentials for one of two possible basis sets of operators. Treating these as single-field, slow-roll inflationary models we then score them with an information-theoretic metric ("minimum description length") that quantifies their efficiency in compressing the information in current data. We explore two possible priors on the parameter space of potentials, one related to the functions' structural complexity and one that uses a Katz back-off language model to prefer functions that may be theoretically motivated. This enables us to identify the inflaton potentials that optimally balance simplicity with accuracy at explaining current data, which may subsequently find theoretical motivation. Our exploratory study opens the door to extraction of fundamental physics directly from data, and may be augmented with more refined theoretical priors in the quest for a complete understanding of the early Universe.

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