Open PhD Positions for 2025
Institute of Theoretical Physics and Astronomy is looking for 7 PhD candidates to join our scientific teams in September 2025.
Proposed PhD research topics:
Theoretical study of reactions involving halo nuclei
Halo nuclei are clusterized nuclear systems with their weakly bound valence neutrons extending far beyond the nuclear core, thereby providing unique opportunities to study nuclear structure and reactions at the limits of stability. Their exotic structure allows to probe shell structures near the neutron dripline and investigate special excitation modes. Their reaction mechanisms differ from stable nuclei and the valence degrees of freedom require a special treatment. Halo nuclei reactions are also crucial for understanding nuclear astrophysics and nucleosynthesis processes.
The PhD work will develop theoretical description of reactions involving halo nuclei, especially the ones with two-particle halos. The weak binding implies the crucial role of the proper continuum treatment; therefore, the description will be attempted using rigorous scattering theory. Its complexity prevents its application in particular extreme cases relevant for reactions with halo nuclei, therefore new methodologies, especially the newly emerging ones based on artificial intelligence and machine learning tools, will be developed and applied. The resulting methodologies may turn out to be useful also in other fields, for example in the cold-atom and universal few-body physics.
Supervisor: Arnoldas Deltuva https://www.ff.vu.lt/en/itpa/staff/deltuva
Study of phenomenological models with additional scalar multiplets
The Standard Model (SM) of particle physics, which includes quantum field theories of the electroweak and strong interactions, provides a remarkably accurate description of matter at the fundamental level. However, specific experimental measurements and cosmological observations – such as neutrino oscillations, Zbb coupling constants, and dark matter – suggest that the SM is incomplete. Consequently, various extensions of the model are explored to provide a theoretical description of these observed phenomena, though they introduce additional parameters. Also, the exact solutions of complex models require significant computational resources, which can grow exponentially with the model's complexity.
During the doctoral studies, innovative methods will be developed to determine the variation spaces of the free parameters in SM extensions, with a particular focus on machine learning techniques. Theoretical constraints, such as unitarity and bounded-from-below conditions, allow to narrow the parameter spaces, but their estimation remains challenging. Therefore, neural networks and machine learning algorithms will be applied and further developed to optimize the numerical computations of the considered models.
Supervisor: Darius Jurčiukonis https://www.ff.vu.lt/en/itpa/staff/jurciukonis
Analysis of neutral boson decay using CERN CMS data
Compact muon solenoid experiment (CMS) at the Large Hadron Collider (LHC) at CERN has been registering proton-proton collisions for over a decade. The third data-taking period (Run3) started in 2023. A greater number of proton-proton collisions during each bunch-crossing has increased the complexity of heavy particle identification, and previously used data analysis methods must be adapted to new conditions. Experimental analysis of both heavy particle production and their decay rates will allow improvements of theoretical models. Data analysis is performed by international research groups. The PhD candidate will learn the CMS data analysis starting from participation in the measurement of the multidimensional reaction cross-section of photon and Z-boson decays using Run2 data. The candidate will have to contribute to technical tasks of the CMS detector.
Supervisor: Andrius Juodagalvis https://www.ff.vu.lt/en/itpa/staff/juodagalvis
Hidden symmetries in integrable Hamiltonian systems
Integrable Hamiltonian systems constitute a broad class of models with applications ranging from cold atoms and semiconductor materials to gauge fields and holography in superstring theory. A distinctive feature of such systems is the large number of integrals of motion signalling the existence of a broad family of hidden symmetries. Such families are called quantum groups. During the doctoral studies, twisted Yangian type quantum groups will be studied in the Drinfeld current presentation. This presentation, proposed by K. Lu, W. Wang and W. Zhang in recent publications arXiv:2308.12254 and arXiv:2408.06981, opens up new possibilities in the spectral analysis of integrable Hamiltonian systems with open boundary conditions. It is planned to develop a highest-weight representation theory of the above-mentioned quantum groups, adapt algebraic Bethe ansatz to the Drinfeld current presentation, and investigate spectral characteristics of selected Hamiltonian systems.
Supervisor: Vidas Regelskis https://www.ff.vu.lt/en/itpa/staff/regelskis
Stabilization and synchronization in periodic systems
Dynamical systems that have periodic solutions are often found both in human-made devices (rotating motors, oscillations in electrical circuits, periodic chemical reactions, sound-induced periodic vibrations) and in natural phenomena (the Earth-Sun system, fluctuations in neuron membrane potential, the dynamics of predator-prey interactions in a closed ecosystem). Often, the natural behaviour of a system is undesirable, so a controller is used to steer the system toward a desirable state. One class of problems is related to enabling/disabling synchronization between coupled oscillators. Another interesting goal in control theory is modifying the stability of a periodic solution (stabilizing/destabilizing it) or filtering out a specific harmonic component from a periodic solution. The latter case arises in the rotating scanning atomic force microscope, where the goal is to filter out the first harmonic from a delayed periodic signal (see arXiv:2403.11731). Using the harmonic oscillator method [https://doi.org/10.1103/PhysRevE.91.012920], controllers will be designed for synchronization, stabilization, and filtering.
Supervisor: Viktor Novičenko http://www.itpa.lt/~novicenko/
Change and exchange processes in complex social systems
Opinion dynamics, a core aspect of the complex social systems research, delves into the process of opinion change. Physical spin-based models offer a convenient framework for modelling opinion dynamics. Thus, current literature focuses on the phase transitions arising under the influence of various semi-realistic social mechanisms. However, this approach does not result in empirically verifiable models. Also, these models feature unrealistically frequent individual opinion shifts. This PhD research topic would consider aforementioned shortcomings by exploring novel variations of the noisy voter model combining opinion change and spatial exchange processes. Introducing spatial dimension aligns the models with the empirical data, which is usually spatial, and allows for a decrease in the frequency of individual opinion change. Furthermore, these models should apply to various social contexts, from exploring the relationship between socio-demographics, political opinions, and societal attention dynamics to trading different assets in financial markets.
Supervisor: Aleksejus Kononovičius http://web.vu.lt/tfai/a.kononovicius/
Lithium abundances as tracers of stellar and Galactic evolution
The aim of the work is to determine lithium abundances in medium- and low-mass stars and to study how changes in abundance depend on the star's atmospheric parameters, age, evolutionary stage, rotation rate, position in the Galaxy and other parameters. Not enough work has been accomplished on this topic in the world to evaluate the current theoretical models of changes in the chemical composition of stars during their evolution and the chemical evolution models of the Milky Way galaxy. The work is important for the study of stellar and Galactic evolution. The research will use high-resolution observations of stellar spectra at VU ITPA Molėtai Astronomical Observatory and other observatories around the world.
Supervisor: Gražina Tautvaišienė https://www.ff.vu.lt/en/itpa/staff/tautvaisiene
Good knowledge in quantum mechanics (for theoretical physics topics) or astrophysics (for the astronomy topic) is expected. Experience in scripting languages (e.g. Python, Wolfram Mathematica) is a plus.
The successful candidates will join the Institute of Theoretical Physics and Astronomy of Vilnius University in Lithuania. The institute consists of 8 groups with research interests in atomic, nuclear and particle physics, complex systems, stellar and exoplanet astrophysics. For more information about our research, visit https://www.ff.vu.lt/en/itpa/structure/research-groups
Funding:
- Fully paid tuition fees for 4 years.
- A tax-free scholarship for 4 years (€15,960 per annum during first year and €18,480 in the subsequent years).
- Additional financial support is provided to cover travel expenses.
- If you are not an EU/EEA national, you will need to apply for a student study visa before admission.
Eligibility
- Applicants should have, or expect to achieve, at least MSc in Physics, Astrophysics or Mathematics disciplines.
How to apply
- Interested candidates should contact Egidijus Anisimovas at or potential supervisors.
- Please include your CV, a motivation letter, academic transcripts of your BSc and MSc studies, names and email addresses of two referees, who will be contacted for letters of recommendation.
Deadline
- 30 May 2025
Additional information:
- PhD Courses in Physics at Vilnius University
- Regulations for Doctoral Studies at Vilnius University
- Doctoral Studies in Natural Sciences at Vilnius University
- Doctoral Committee for Natural Sciences at Vilnius University
- For general inquiries please contact Kristina Aponienė, Saulėtekio av. 3, B232 room, tel. +370 (5) 223 4502, email:
Current and Past PhD Students
PhD Students of VU ITPA
Bruno Ćurjurić (2024-2028)
Vilius Bagdonas (2023-2027)
Eimantas Ledinauskas (2022-2026)
Edvinas Gvozdiovas (2022-2026)
Aurimas Vitkus (2022-2026)
Yakov Braver (2021-2025)
Barkha Bale (2021-2025)
Marijus Ambrozas (2020-2024)
Ashutosh Sharma (2020-2025)
Rigonda Skorulskienė (2020-2025)
Rūta Adomavičienė (2020-2025)
Former PhD Students of VU ITPA:
Šarūnas Jacevičius (2023-2024)
Markus Ambrosch (2019 - 2023)
Simonas Draukšas (2019 - 2023)
Edgaras Kolomiecas (2016 - 2023)
Jurgita Koncevičiūtė (2016 - 2021)
Giedrius Žlabys (2017 - 2021)
Mantas Račiūnas (2017 - 2021)
Carlos Viscasillas Vázquez (2017 - 2021)
Saulius Pakalka (2016 - 2020)
Žydrūnė Misikonytė (2016 - 2018)
Jonas Bialopetravičius (2015 - 2019)
Gintaras Kerevičius (2014-2019)
Vytautas Dūdėnas (2014 - 2018)
Tomas Andrijauskas (2013-2017)
Rytis Kazakevičius (2013-2017)
Hamid Reza Hamedi (2013-2017)
Laima Radžiūtė (2012-2016)
Vaidas Juknevičius (2012-2016)
Arnas Drazdauskas (2012-2016)
Mindaugas Macijauskas (2012-2016)
Algimantas Černiauskas (2012-2016)
Jonas Klevas (2012-2016)
Aleksejus Kononovičius (2011-2015)
Kristupas Milašius (2011-2014)
Adolfas Šliogeris (2011-2013)
Dainius Prakapavičius(2010-2014)
Renata Ženovienė (2010-2014)
Vytautas Čepas (2010-2014)
Šarūnas Masys (2009-2013)
Tomas Sabonis (2008-2015)
Gintaras Barisevičius (2008-2012)
Edita Stonkutė (2008-2012)
Marius Maskoliūnas (2008-2012)
Šarūnas Mikolaitis (2007-2011)
Vidas Regelskis (2006-2010)
Eduardas Puzeras (2006-2010)
Žilvinas Ežerinskis (2006-2010)
Rytis Juršėnas (2006-2010)
Viačeslavas Nelkinas (2005-2009)
Olga Rancova (2004-2008)
Darius Jurčiukonis (2003-2007)
Julius Ruseckas (2002-2006)
Oliver Scharf (2002-2006)
Miglius Alaburda (1999-2003)
Vygandas Laugalys (1995-2000)
Justas Zdanavičius (1994-2000)
Past PhD Projects
Dissertation author: Edgaras Kolomiecas
Disertacijos pavadinimas: „Galaktikos kamuolinio žvaigždžių spiečiaus 47 Tukano cheminė raida“
Dissertation title: "Chemical Evolution of Galactic Globular Cluster 47 Tucanae"
Dissertation (EN) and Summary (LT, page 113)
Dissertation author: Markus Ambrosch
Disertacijos pavadinimas: „Žvaigždžių atmosferų tyrimas su konvoliuciniais neuroniniais tinklais“
Dissertation title: "Investigating Stellar Atmospheres with Convolutional Neural Networks"
Dissertation (EN) and Summary (LT, page 105)
Dissertation author: Simonas Draukšas
Disertacijos pavadinimas: „Grimus-Neufeld modelio renormalizacija“
Dissertation title: "Renormalization of the Grimus-Neufeld model"
Dissertation (EN) and Summary (LT, page 129)
Dissertation author: Jurgita Koncevičiūtė
Disertacijos pavadinimas: „Teorinis dvigubos ir trigubos jonizacijos elektronais tyrimas taikant kelių žingsnių metodą“
Dissertation title: "Theoretical Study of Electron-Impact Double and Triple Ionization Using a Multi-Step Approach"
Dissertation (EN) | Summary (LT)
Dissertation author: Carlos Viscasillas Vázquez
Disertacijos pavadinimas: „Neutronų pagavimo cheminių elementų gausėjimo Paukščių Tako galaktikoje raida“
Dissertation title: "Chemical abundances of neutron-capture elements in the Milky Way"
Dissertation (EN) and Summary (LT, page 175)
Dissertation author: Giedrius Žlabys
Disertacijos pavadinimas: „Šaltųjų atomų dinamika kvazivienmatėse optinėse gardelėse“
Dissertation title: "Ultracold atom dynamics in quasi-one-dimensional optical lattices"
Dissertation (EN) and Summary (LT, page 109)
Dissertation author: Saulius Pakalka
Disertacijos pavadinimas: „Tiesioginės ir netiesioginės viengubos jonizacijos elektronų smūgiais tyrimas“
Dissertation title: "Theoretical study of direct and indirect single ionisation by electron impact"
Dissertation (EN) | Summary (LT)
Dissertation author: Jonas Bialopetravičius
Disertacijos pavadinimas: „Žvaigždžių spiečių analizė konvoliuciniais neuroniniais tinklais“
Dissertation title: "Analysis of Star Clusters with Convolutional Neural Networks"
Dissertation (EN)
Dissertation author: Algimantas Černiauskas
Disertacijos pavadinimas: „Galaktikos kamuolinio žvaigždžių spiečiaus Tukano 47 cheminės ir kinematinės savybės.“
Dissertation title: "Chemical and kinematical properties of Galactic globular cluster 47 Tucanae
Dissertation (EN) and Summary (LT, page 96)
Dissertation author: Hamid Reza Hamedi
Disertacijos pavadinimas: „Tiesiniai ir netiesiniai lėtos šviesos reiškiniai“
Dissertation title: "Linear and nonlinear phenomena for slow light"
Dissertation (EN) | Summary (LT)
Dissertation author: Dainius Prakapavičius
Disertacijos pavadinimas: „Deguonis žvaigždžių atmosferose: spektro linijų formavimasis ir gausa“
Dissertation title: "Oxygen in stellar atmospheres: spectral line formation and abundances"
Dissertation (EN) | Summary (LT)
Dissertation author: Jonas Klevas
Disertacijos pavadinimas: „Konvekcijos ir nelokalaus spinduliuotės lauko įtaka spektro linijų formavimuisi žvaigždžių atmosferose“
Dissertation title: "The influence of convection and non-local radiative field on spectral line formation in stellar atmospheres"
Dissertation (EN) | Summary (LT)
Dissertation author: Aleksėjus Kononovičius
Disertacijos pavadinimas: „Finansų rinkų ir socialinių procesų modeliavimas statistinės fizikos metodais“
Dissertation title: "Applications of Statistical Physics in Modeling of Financial Markets and Social Processes"
Dissertation (EN) | Summary (LT)
Dissertation author: Arnas Drazdauskas
Disertacijos pavadinimas: „Evoliuciniai anglies ir azoto gausų pokyčiai mažos masės metalingose žvaigždėse“
Dissertation title: "Evolutionary carbon and nitrogen abundance alterations in low mass metal-abundant stars"
Dissertation (EN) | Summary (LT)
Dissertation author: Vytautas Čepas
Disertacijos pavadinimas: „Galaktikos struktūra ir žvaigždėdara H II srities SH2-205 aplinkoje“
Dissertation title: "Galactic structure and star formation in the vicinity of H II region SH2-205"
Dissertation (EN) | Summary (LT)
Dissertation author: Šarūnas Masys
Disertacijos pavadinimas: „Perovskitinių kristalų elektroninės ir kristalinės sandaros tyrimas“
Dissertation title: "Investigation of electronic and crystalline structure of perovskite crystals"
Dissertation (EN) | Summary (LT)
Dissertation author: Renata Ženovienė
Disertacijos pavadinimas: „Cheminės sudėties tyrimas galaktikos žvaigždžių substruktūrose“
Dissertation title: "Chemical composition study of galactic stellar substructures"
Dissertation (LT) | Summary (EN)
Dissertation author: Marius Maskoliūnas
Disertacijos pavadinimas: „Cefėjo žvaigždėdaros rajonų tyrimas“
Dissertation title: "Investigation of star forming regions in Cepheus"
Dissertation (EN) | Summary (LT)
Dissertation author: Edita Stonkutė
Disertacijos pavadinimas: „Cheminė kinematiškai identifikuotos galaktikos žvaigždžių grupės sudėtis“
Dissertation title: "Chemical composition of kinematically indentified galactic stellar group"
Dissertation (LT) | Summary (EN)
Dissertation author: Šarūnas Mikolaitis
Disertacijos pavadinimas: „Evoliuciniai cheminės sudėties efektai padrikųjų spiečių raudonosiose milžinėse“
Dissertation title: "Evolutionary Effects of Chemical Composition in Red Giants of Open Clusters"
Dissertation (EN) | Summary (LT)
Dissertation author: Eduardas Puzeras
Disertacijos pavadinimas: „Evoliuciniai cheminės sudėties pokyčiai helį centre deginančių žvaigždžių atmosferose“
Dissertation title: "Evolutionary Effects in Helium Core Burning Star Atmospheres"
Dissertation (EN) | Summary (LT)
Dissertation author: Rytis Juršėnas
Disertacijos pavadinimas: „Algebrinis daugiadalelės trikdžių teorijos plėtojimas teorinėje atomo spektroskopijoje“
Dissertation title: "Algebraic development of many-body perturbation theory in theoretical atomic spectroscopy"
Dissertation (EN) | Summary (LT)
Dissertation author: Olga Rancova
Disertacijos pavadinimas: „Kvazireliatyvistinio artinio plėtojimas atomų ir jonų spektrinėms charakteristikoms teoriškai tirti“
Dissertation title: "Development Of Quasirelativistic Approach For Investigation Of Spectral Characteristics Of Atoms And Ions"
(Disertacija) | (Santrauka)
Dissertation author: Vygandas Laugalys
Disertacijos pavadinimas: „Jaunos žvaigždės ir tarpžvaigždinė ekstinkcija šiaurės amerikos ir pelikano debesyse“
Dissertation title: "Young stars and interstellar extinction in the North America and Pelican Nebulae"
Dissertation (EN) | Summary (LT)
Dissertation author: Darius Jurčiukonis
Disertacijos pavadinimas: „SU(3) topologinių solitonų kanoninis kvantavimas“
Dissertation title: "Canonical quantization of SU(3) topological solitons"
Dissertation (EN) | Summary (LT)
Dissertation author: Oliver Scharf
Disertacijos pavadinimas: „Hipersmulkiųjų sąveikų daugiaelektroniuose atomuose teorijos plėtojimas“
Dissertation title: "On the Theory of Hyperfine structure of Many-Electron atoms"
Dissertation (EN) | Summary (LT)
Dissertation author: Justas Zdanavičius
Disertacijos pavadinimas: „Tarpžvaigždinė ekstincija Žirafos tamsiųjų debesų kryptimi“
Dissertation (EN)
Dissertation author: Julius Ruseckas
Disertacijos pavadinimas: „Matavimo modeliai kvantiniu Zenono ir anti-Zenono efektu aprašymui ir laiko kvantineje mechanikoje apibrežimui“
Dissertation title: "Measurement Models for Quantum Zeno andanti-Zeno Effects and Time Determination in Quantum Mechanics"
Dissertation (EN) | Summary (LT)
Dissertation author: Miglius Alaburda
Disertacijos pavadinimas: „Taškinių procesų 1/f triukšmo modeliavimas“
Dissertation title: "Point processes modeling of 1/f noise"
Dissertation (EN) | Summary (LT)