Theoretical cosmology

Goal: Understand the mathematical models of modern cosmology and their physics applications. Physical cosmology relates to a few other fields of science, such as astrophysics, astroparticle physics (a.k.a. particle astrophysics) and astronomy. Modern cosmology is grounded in general relativity and closely connected to quantum field theory on curved spacetime.
 
Group leader: Paul Tudorache
 
Group members: Paul Tudorache
 
Supervisors: Calin Lazaroiu and Mirela Babalic
 
Online resources for observational and computational aspects:
 
 
Some regional links
 
Romania's ISS | ROSA | Poland's SRC | Copernicus Center of the PAS
 
Charts of the history of the universe from NASA and ESA.
A summary of the history of the universe.
Planck 2018 results | ACT results | SPT
Gravitational wave detectors: LIGO | VIRGO | KAGRA | GEO600
Multimessenger astronomy and astrophysics
The Space Science website of the ESA
The Origins website of JAXA.
Simulations of structure formation in the ΛCDM model: MilleniumTNG | Universe machine
 
 
Bindi et al, Cosmic ray physics
 
 
 
Bailes et al, Gravitational-wave physics and astronomy in the 2020s and 2030s, Nature Reviews Physics 3 (2021) 344-366.
Flanaghan and Hughes, The basics of gravitational wave theory, New. J. Phys 7 (2005) 204.
 
 
Caprini, Strong evidence for the discovery of a gravitational wave background, Nature Reviews Physics 6 (2024) 291-293.
 
Scheme:
 
I. Basic cosmology
 
A. Cosmological solutions
B. FLRW spacetimes and equations of state
C. The basic history of the universe
D. Problems of early universe cosmology
E. Basic theory of one-field cosmological models
F. Special subjects
Bonus: Historical note.
 
References:
 
Introductory
 
 
Intermediate to advanced
 
Ellis, Maartens and MacCallum, Relativistic cosmology
Dodelson and Schmidt, Modern cosmology
Weinberg,  Cosmology
 
Special subjects
 
 
 
 
COMPACT collaboration, Promise of Future Searches for Cosmic Topology, Phys. Rev. Lett. 132 (2024) 171501.
P. M. Vaudrevage et al, Constraints on the topology of the Universe: Extension to general geometries, Phys. Rev. D 86 (2012) 083526.
M. Lachieze-Rey, J. P. Luminet, Cosmic topology, Phys. Rep. 254 (1995) 135-214.
 
Dark matter:
 
Cirelli et. al, Dark Matter, arXiv:2406.01705 [hep-ph]
 
Structure formation
 
Primack, Galaxy Formation in ΛCDM Cosmology, Annu. Rev. Nucl. Part. Sci. 2024. 74 (2024) 173-206.
 
Primordial black holes
 
Arbey, Primordial black holes: a small review, arXiv:2405.08624 [gr-qc].
Escriva et al, Primordial black holes, in Sedda et al (eds), Black Holes in the Era of Gravitational-Wave Astronomy, Elsevier, 2024, pp. 261-377.
 
 
II. Single-field early universe cosmology
 
B. Single field cosmological perturbation theory
C. The slow roll and psi-expansions of single-field models
D. Dynamical systems methods and attractors in single-field models
E. Reheating
F. Stochastic inflation
 
References:
 
A. The ADM formalism
 
Giulini, Dynamical and Hamiltonian formulation of general relativity, in Springer Handbook of Spacetime, Springer, 2014.
Corichi and Nunez, Introduction to the ADM formalism, Rev. Mex. Fis. 37 (1991) 4, 720-747.
Arnowitt, Deser and Misner, The dynamics of general relativity (republication of the 1962 classic paper).
 
CQG, WDW equation, "Quantum cosmology" and the Hartle-Hawking "no bounday" proposal
 
Cianfrani et al, Canonical Quantum Gravity
J.L. Lehners, Review of the no-boundary wave function, Phys. Rep. vol. 1022 (2023) 1-82.
 
B. Single field cosmological perturbation theory
 
Brandenberger, Lectures on the theory of cosmological perturbations, Lect. Notes in Physics 646 (2004) 127-167.
Mukhanov, Feldman, Brandenberger,  Theory of Cosmological Perturbations, Phys Rep. vols 215 & 216.
Bardeen, Gauge-invariant cosmological perturbations, Phys. Rev. D 22 (1980) 1882.
Salopek, Bond and Bardeen, Designing density fluctuation spectra in inflation, Phys. Rev. D 40 (1989) 1753.
Uggla and Wainwright, Cosmological perturbation theory revisited, Class Quantum Grav, 28 (2011) 175017.
 
C. The slow roll and psi-expansions of single-field models
 
Liddle, Parsons, Barrow, Formalizing the slow-roll approximation in inflation, Phys. Rev. D 50 (1994) 7222.
C. I. Lazaroiu, On the slow roll expansion of one-field cosmological models, Nucl. Phys. B 1000 (2024) 116466.
E. Medina, L. M. Alonso, Kinetic dominance and psi series in the Hamilton-Jacobi formulation of inflaton models, Phys. Rev. D 102 (2020) 103517.
W. Handley, A. Lasenby, M. Hobson, Logolinear series expansions with applications to primordial cosmology, Phys. Rev. D 99 (2019) 123512.
 
D. Dynamical systems methods and attractors in single-field models
 
Rendall, Cosmological models and center manifold theory, Gen. Rel. Grav. 34 (2002) 1277.
Rendall, Late-time oscillatory behaviour for self-gravitating scalar fields, Class. Quant. Grav. 24 (2007) 667.
Ahlo and Uggla, Global dynamics and inflationary center manifold and slow-roll approximants, J. Math. Phys. 56 (2015) 012502.
Ahlo, Hell, Uggla, Global dynamics and asymptotics for monomial scalar field potentials and perfect fluids, Class Quantum Grav. 32 (2015) 145005.
Alvarez, Alonso, Medina & Vazquez, Separatrices in the Hamilton-Jacobi Formalism of Inflaton Models, J. Math. Phys. 61 (2020) 043501.
 
E. Reheating
 
 
F. Stochastic inflation
 
Launay et al, Stochastic inflation in general relativity, Phys. Rev. D 109 (2024) 123523.
Pattison et al, Stochastic inflation beyond slow roll, JCAP 07 (2019) 031.
 
III. Two-field and multifield early universe cosmology
 
A. Basic theory. Kinematic and dynamical parameters
B. Formulation as geometric dynamical systems. Cosmological observables
C. The SRST and SRRT conditions
D. SRST inflation
E. Rapid turn inflation
F. Noether symmetries
G. Multifield cosmological perturbation theory
H. Reheating in multifield models
K. Stochastic inflation in multifield models
L. Constraining multifield inflation using observational data

References:
 
A. Basic theory. Kinematic and dynamical parameters
 
A. Hetz, G.A. Palma, Sound Speed of Primordial Fluctuations in Supergravity Inflation, Phys. Rev. Lett. 117 (2016) 101301.
 
B. Formulation as geometric dynamical systems. Cosmological observables
 
E. M. Babalic, C. I. Lazaroiu, The infrared behavior of tame two-field cosmological models, Nucl. Phys. B 983 (2022) 115929.
C. I. Lazaroiu, Natural observables and dynamical approximations in multifield cosmological models, Int. J. Mod. Phys. A. 38 (2023) 32, 2343007.
 
C. The SRST and SRRT conditions
 
C. M. Peterson, M. Tegmark, Testing Two-Field Inflation, Phys. Rev. D 83 (2011) 023522.
L. Anguelova, C. I. Lazaroiu, Dynamical consistency conditions for rapid turn inflation, JCAP 05 (2023) 020.
 
D. SRST inflation
 
C. M. Peterson, M. Tegmark, Testing Two-Field Inflation, Phys. Rev. D 83 (2011) 023522.
C. M. Peterson, M. Tegmark, Non-Gaussianity in Two-Field Inflation, Phys. Rev. D 84 (2011) 023520.
 
E. Rapid turn inflation
 
General features
 
D.-G. Wang. G. L. Pimentel, A. Achucarro, Bootstrapping Multi-Field Inflation: non-Gaussianities from light scalars revisited, JCAP 05 (2023) 043.
O. Yaryghina, M.C.D. Marsh, G. Salinas, Non-Gaussianity in rapid-turn multi-field inflation, JCAP 03 (2024) 014.
 
Models
 
A. Brown, Hyperinflation, Phys. Rev. Lett. 121 (2018) 251601.
S. Mizuno, S. Mukohyama, Primordial perturbations from inflation with a hyperbolic field space, Phys. Rev. D 96 (2017) 103533.
S. Garcia-Saenz, S. Renaux-Petel, J. Ronayne, Primordial fluctuations and non-Gaussianities in sidetracked inflation, JCAP 1807 (2018) 057.
P. Christodoulidis, D. Roest, E. Sfakianakis, Angular inflation in multi-field α-attractors, JCAP 11 (2019) 002.
J. Ellis, M. Garcia, D. Nanopoulos, K. Olive, Two-Field Analysis of No-Scale Supergravity Inflation, JCAP 01 (2015) 010.
 
F. Noether symmetries
 
L. Anguelova, E. M. Babalic, C. I. Lazaroiu, Hidden symmetries of two-field cosmological models, JHEP 09 (2019) 007.
 
G. Multifield cosmological perturbation theory
 
C. M. Peterson, M. Tegmark, Non-Gaussianity in Two-Field Inflation, Phys. Rev. D 84 (2011) 023520.
 
In spatially flat gauge
 
J. Elliston, D. Seery, R. Tavakol, The inflationary bispectrum with curved field-space, JCAP 1211 (2012) 060.
D. Seery, J. E. Lidsey,  Primordial non-gaussianities from multiple-field inflation, JCAP 0509 (2005) 011.
D. Langlois, S. Renaux-Petel, Perturbations in generalized multi-field inflation, JCAP 0804 (2008) 017.
D. Langlois, S. Renaux-Petel, D. A. Steer, T. Tanaka, Primordial perturbations and non-Gaussianities in DBI and general multifield inflation, Phys. Rev. D78 (2008) 063523.
E. Tzavara, B. van Trent, Gauge-invariant perturbations at second order in two-field inflation, JCAP 1208 (2012) 023.
E. Tzavara, S. Mizuno, B. van Tent, Covariant second-order perturbations in generalized two-field inflation, JCAP 1407 (2014) 027.
 
In "comoving" gauge
 
S. Garcia-Saenz, L. Pinol and S. Renaux-Petel, Revisiting non-Gaussianity in multifield inflation with curved field space, JHEP01 (2020) 073.
 
Structural
 
L. Pinol, S. Renaux-Petel, D. Werth, The Cosmological Flow: A Systematic Approach to Primordial Correlators, arXiv:2312.06559 [astro-ph.CO].
 
H. Reheating in multifield models
 
J. Martin, L. Pinol, Opening the reheating box in multifield inflation, JCAP 12 (2021) 022.
 
K. Stochastic inflation in multifield models
 
M. Honda, R. Jinno, L. Pinol, K. Tokeshi, Borel resummation of secular divergences in stochastic inflation, JHEP08 (2023) 060.
A. Achucarro, S. Cespedes, A.-C. Davis, G. A. Palma, The hand-made tail: non-perturbative tails from multifield inflation, JHEP05(2022)052.
 
L. Constraining multifield inflation using observational data
 
Cabass et al, Constraints on multifield inflation from the BOSS galaxy survey, Phys. Rev. D 106 (2022) 043506.
A. Salvio, S. Sciusco, (Multi-field) natural inflation and gravitational waves, JCAP03 (2024) 018.