Lavrentios Kazantzidis


Personal Information

(+30) 26510 - 08451
Lavrentios Kazantzidis

Research Interests

My main research interests include theoretical and astrophysical aspects of cosmology, modified gravity theories (extensions of General Relavity), as well as cosmological data analysis.

Short Curriculum Vitae


2017 – Present   
Ph.D. in Physics
                                Thesis Title: “Cosmological Aspects of Scalar Tensor Theories of Gravity”
                                Department of Physics, University of Ioannina
2015 – 2017         Postgraduate Studies (M.Sc.) in Physics
                                Graduated with an overall grade 8.44/10.00
                                Department of Physics, University of Ioannina
2011 – 2015         Bachelor of Science certificate (B.Sc.) in Physics
                                Graduated with an overall grade 7.47/10.00
                                Department of Physics, University of Ioannina


2018 – Present    Cosmological Aspects of Modified Theories of Gravity
                                Fellow of the Greek State Scholarships Foundation (IKY) for Ph.D. Studies.
2020 – Present    Tilted Cosmology
                                Role: Partner
                                Funding Source: Hellenic Foundation of Research and Innovation (HFRI) – “1st Call for Hellenic Foundation for Research and
                                Innovation Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment”.

Computer Skills

Operating Systems     Windows & Linux
Programming               C & Wolfram Mathematica
Scientific Software     (MG)CAMB, (MG)COSMOMC, CLASS, MontePython, LaTeX


Greek        Native
English      First Certificate in English (FCE)
                   Examination for the Certificate of Competency in English (ECCE)
French       Diplôme d’études en langue française (DELF) B1


2018 – Present    Junior Member of the Hellenic Society on Relativity, Gravitation and Cosmology

Publication Record

For the full list of my publications please visit the inspirehep database.

A w – M phantom transition at zt<0.1 as a resolution of the Hubble tension
G. Alestas, L. Kazantzidis, L. Perivolaropoulos
arXiv:2012.13932, Supplemental Material

Hints for possible low redshift oscillation around the best fit ΛCDM model in the expansion history of the universe
L. Kazantzidis, H. Koo, S. Nesseris, L. Perivolaropoulos, A. Shafieloo
Mon.Not.Roy.Astron.Soc. 501 (2021) 3, 3421-3426
DOI: 10.1093/mnras/staa3866

H0 tension, phantom dark energy, and cosmological parameter degeneracies
G. Alestas, L. Kazantzidis, L. Perivolaropoulos
Phys.Rev.D 101 (2020) 12, 123516
DOI: 10.1103/PhysRevD.101.123516, Supplemental Material

Hints of a Local Matter Underdensity or Modified Gravity in the Low z Pantheon data
L. Kazantzidis, L. Perivolaropoulos
Phys.Rev.D 102 (2020) 2, 023520
DOI: 10.1103/PhysRevD.102.023520, Supplemental Material

Hints of modified gravity in cosmos and in the lab?
Leandros Perivolaropoulos, Lavrentios Kazantzidis
Int.J.Mod.Phys.D 28 (2019) 05, 1942001, Invited Review for Special Issue on Modified Gravity
DOI: 10.1142/S021827181942001X

Constraining power of cosmological observables: blind redshift spots and optimal ranges
L. Kazantzidis, L. Perivolaropoulos, F. Skara
Phys.Rev.D 99 (2019) 6, 063537
DOI: 10.1103/PhysRevD.99.063537, Supplemental Material

Is gravity getting weaker at low z? Observational evidence and theoretical implications
Lavrentios Kazantzidis, Leandros Perivolaropoulos
Invited contribution for the White Paper of COST CA-15117 project “CANTATA” (Cosmology and Astrophysics Network for Theoretical Advances and Training   Actions) “Observational Discriminators” section.
arXiv: 1907.03176, Supplemental Material

Evolution of the 8 tension with the Planck15/ΛCDM determination and implications for modified gravity theories
Lavrentios Kazantzidis, Leandros Perivolaropoulos
Phys.Rev.D 97 (2018) 10, 103503
DOI: 10.1103/PhysRevD.97.103503, Supplemental Material

Consistency of modified gravity with a decreasing  Geff (z) in a ΛCDM background
Radouane Gannouji, Lavrentios Kazantzidis, Leandros Perivolaropoulos, David Polarski
Phys.Rev.D 98 (2018) 10, 104044
DOI: 10.1103/PhysRevD.98.104044


Teaching Assistance

Winter Semesters 2017 – Present     Classical Electrodynamics I (5th Semester Core Course – 52 )
                                                                  Department of Physics, University of Ioannina, Greece
Spring Semesters 2020 – Present     Cosmology (Advanced Undergraduate Elective Course – 105)
                                                                  Department of Physics, University of Ioannina, Greece
Spring Semesters 2018 – 2019         Gravity and Cosmology (Advanced Graduate Elective Course – M122) 
                                                                  Department of Physics, University of Ioannina, Greece

Postgraduate Diploma Thesis

Title: Dark Energy from Generalized Gravitational Theories with a Time-dependent Newton’s Constant (scalar tensor theories).
This work is focused on alternative forms of Dark Energy. The challenges that the ΛCDM model faces led to a variety of alternative models, such as extra dimensions, quintessence models, $f(R)$ extended gravity theories, scalar tensor quintessence models etc. The main goal of my master thesis is to investigate the cosmological dynamics for general scalar tensor quintessence field models. Firstly, we introduce the reader to the mathematical formalism of  Standard Cosmology and then, we study alternative theories that can play the role of Dark Energy such as quintessence models based on linear-negative potentials of the form $V (\phi) = −s \, \phi$. In the second part of this work we review the scalar tensor quintessence field models and their theoretical background. We investigate the equation of state parameter $w(z)$ for these particular models and we use the Union2.1 dataset of 580 SnIa as a validity test and to explore the observational consistency of the theoretical model and its predictions for the fate of our Universe. Finally we study qualitatively different potentials of the form $V = s \, |\phi|^{n}$ and use, once again the Union2.1 dataset as a consistency test of our model.  

You can see my full M.Sc. thesis he