Students and graduates of PhD studies with supervisors from ITP (since 2001)
Students
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
|---|---|---|---|---|
| Alejandro Luis García Munoz |
Electron-molecule collisions and attosecond time-delays for molecular iodine
|
Mgr. Zdeněk Mašín, Ph.D. | 1 | |
| Jan Hrubeš |
Geometry of circular space-times
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doc. RNDr. Oldřich Semerák, Ph.D., DSc. | 1 | |
| Marco Aurelio Laversveiler Paiva |
Unveiling binary star evolution through theoretical models and observational data
|
doc. Mgr. Ondřej Pejcha, Ph.D. | 1 | |
| Alejandro Dylan Rowlands Doblas |
The Role of Substructure in Gravitational Lensing by Galaxy Clusters
|
doc. Mgr. David Heyrovský, Ph.D. | 1 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Martin Crhán |
Ultrafast electronic and nuclear dynamics in molecules studied by attosecond time-delays
|
Mgr. Zdeněk Mašín, Ph.D. | 2 | |
| Hryhorii Ovcharenko |
Investigation of exact gravitational fields
|
prof. RNDr. Jiří Podolský, CSc., DSc. | 2 | |
| Matúš Papajčík |
Exact 2+1 spacetimes and their relation to solutions in other gravity theories
|
Exact 2+1 spacetimes and their relation to solutions in other gravity theoriesThe aim of this work will be the study of exact spacetimes of gravity theory in three dimensions, and their comparison with analogous solutions of Einstein’s field equations in general relativity in four and higher dimensions. The main topic will be an algebraic classification, geometric analysis, and physical interpretation of the complete class of solutions which were found in our recent works, involving all such spacetimes without matter (including any value of the cosmological constant), with pure radiation (possibly with a gyratonic sources), and also electromagnetic field. |
prof. RNDr. Jiří Podolský, CSc., DSc. | 2 |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Eliška Klimešová |
Multiple black holes in theories of gravity, their dynamics and signatures
|
Multiple black holes in theories of gravity, their dynamics and signaturesThe goal of the thesis is to study spacetimes containing more than one black hole. The student will explore possible static or stationary configurations of multiple black holes with diverse asymptotics and possibly immersed in various external fields. They will also attempt to extend to higher dimensions previous analyses of slow-motion perturbations of static multi black-hole spacetimes. |
doc. RNDr. Martin Žofka, Ph.D. | 3 |
| Álvaro Rafael Martínez Gómez |
New horizons in back-reaction
|
New horizons in back-reactionA body of finite mass moving in an ambient space-time will never move on a geodesic of said space-time; it will perturb the space-time, and this will back-react on its motion. In many physical settings this leads to the emission of gravitational waves and a merger of the components of the system. Similarly, a charge moving in an electromagnetic field or a color-charge moving in a Yang-Mills field will never quite move as a test particle; it will also back-react on its own motion. All these effects are also known as self-force. The aim of this project will be to investigate various field-theoretical setups with back-reaction and see what we can learn from them about the field theories. Ultimately, we will aim to derive results useful for gravitational-wave science. The direction of the project can be to investigate the structure and meaning of the Bern-Carrasco-Johansson double copy, to build electromagnetic analogues of gravitational-wave inspirals into black holes, or focus on issues in the gravitational equations of motion. |
Mgr. Vojtěch Witzany, Ph.D. | 3 |
| Jan Šenk |
Full quantum dynamics of the interparticle Coulombic electron capture
|
doc. RNDr. Přemysl Kolorenč, Ph.D. | 3 | |
| Poula Tadros Nashed |
Higher derivatives and nonlocality in gravity
|
Higher derivatives and nonlocality in gravityTerms with derivatives of higher order appear naturally in many effective descriptions of quantum gravity. They tend to resolve or mitigate issues related to ultraviolet incompleteness of general relativity such as the existence of spacetime singularities and quantum non-renormalizability. Higher-derivative theories of finite order suffer from Ostrogradsky instability, which manifests in the presence of ghost degrees of freedom at the linear level [1]. Gravitational theories can be rendered ghost-free if they reduce to general relativity at the linear level [2] or if they avoid Ostrogradsky's theorem by admitting non-local terms with derivatives of infinite order [3]. Non-local scalar field theories arise also from popular models of p-Adic string theory, string field theory, and non-commutative geometry [4]. The project aims to study various problems of gravitational theories and scalar field theories (in the presence of gravity) that contain higher derivatives of finite or infinite order (non-local theories). The research will focus on solving some of the following problems: exact and approximate solutions of higher-derivative theories of gravity [5,6], higher-derivative scalar field theories in curved spacetimes from the classical and quantum viewpoint [7,8], regularity of fields and curvature in the context of functions and (non-linear) distributions [9,10], Gallean and Carrollian limits of higher-derivative and non-local theories [11], non-local theories based on non-commutative geometry [12]. |
Mgr. Ivan Kolář, Ph.D. | 3 |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Ujjwal Agarwal |
New theoretical frameworks for compact objects and their perturbations
|
New theoretical frameworks for compact objects and their perturbationsThe detection of gravitational waves (GW) has revolutionized our way of observing the Universe. Thanks to GW signals, we can now explore features of astrophysical objects which were impossible to detect only a few years ago. In particular, we can probe deeper into the structure of compact relativistic objects and their evolution. Such an advance in detection measurement requires an equal advance in theoretical tools within which such objects can be understood. This project aims to develop such tools. In particular, the objective will be to use covariant formalisms to construct relativistic models of compact stars and study their properties with particular attention to the interaction that such objects might have with gravitational waves. This work involves the careful study of solutions of the equations of relativistic hydrostatic equilibrium and the determination of the evolution of the perturbations of such solutions. The project will start with the analysis of compact objects solutions in the context of General Relativity considering several (combinations of) fluid sources. The knowledge acquired by this preliminary activity will be applied to the study of these solutions in the context of extensions of General Relativity. The aim will be to consolidate our lore on the known theoretical models and offer a way to test General Relativity using the new data coming from the present and next generation of gravitational waves detectors. |
Dr. Sante Carloni, M.A., Ph.D. | 4 |
| Cynthia Belen Arias Pruna |
Hidden Symmetries and Black Hole Chemistry
|
Hidden Symmetries and Black Hole ChemistryThe student will: 1) Explore new venues for hidden symmetries and their applications to black hole physics and beyond, and 2) Understand black hole chemistry in the context of the AdS/CFT correspondence, and study its implications for black hole microstructure and black hole phase transitions. |
doc. Mgr. David Kubizňák, Ph.D. | 4 |
| Natalia Astudillo |
Exact spacetimes in higher order gravity theories
|
Exact spacetimes in higher order gravity theoriesStudent se seznámí s teoriemi rozšiřujícími Einsteinovu obecnou relativitu o korekce vyšších řádů. Bude analyzovat a zobecňovat vhodné metody řešení rovnic gravitačního pole spolu se studiem konkrétních prostoročasů a jejich fyzikálních a matematických vlastností. |
doc. RNDr. Robert Švarc, Ph.D. | 4 |
| Jana Menšíková |
Classical and Quantum Aspects of Black Holes
|
Classical and Quantum Aspects of Black HolesThe student working on this project will attack some of the following problems. 1) Understand the black hole chemistry in the context of the AdS/CFT correspondence, and its implications for black hole microstructure. 2) Explore new venues for hidden symmetries and their applications. 3) Probe modified gravity theories. 4) Study quantum information aspects of curved spacetimes. |
doc. Mgr. David Kubizňák, Ph.D. | 4 |
| Anthony Kirilov |
Radiation hydrodynamics of transients associated with binary star interactions
|
Radiation hydrodynamics of transients associated with binary star interactionsThe origin of gravitational wave sources (binary black holes and double neutron stars on close orbits) is one of the most captivating problems of contemporary astrophysics. Perhaps the most explored evolutionary scenario involves a common envelope evolution episode in an isolated binary star. A new window into this phase has been provided by steadily growing number of luminous red novae (LRNe)/intermediate luminosity optical transients (ILOTs). The immediate goal of this thesis is to perform multidimensional radiation hydrodynamic simulations of LRNe/ILOTs, compare the results to observed events, and formulate implications for the physics of common envelope evolution, stellar mergers, and gravitational wave events. This topic will be followed up by other projects in the field of transient and theoretical astrophysics making use of hydrodynamics with radiation or magnetic fields, (semi)analytic models, or stellar evolution calculations. |
doc. Mgr. Ondřej Pejcha, Ph.D. | 4 on hiatus |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Šimon Knoška |
Non-twisting geometries in general relativity and its extensions
|
Non-twisting geometries in general relativity and its extensionsStudent prozkoumá obecné vlastnosti geometrií charakterizovaných přítomností světelné geodetické kongruence s nulovým twistem. Analyzuje jejich algebraickou strukturu a chování volných testovacích částic. Dále se zaměří na studium explicitních prostoročasů této třídy v obecné relativitě a jejích zobecněních. |
doc. RNDr. Robert Švarc, Ph.D. | 5 |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Claudia Caputo |
Geodesic chaos in perturbed black-hole fields
|
Geodesic chaos in perturbed black-hole fieldsGeodesic motion is completely integrable in the fields of isolated stationary black holes, but it may become chaotic if there exists some additional source in the space-time. Motivated by accreting black holes in astrophysics, we have studied the geodesic dynamics in the field of a Schwarzschild black hole encircled by a thin disc or a ring (see [1] for the last paper of our series devoted to this topic). Hitherto, we restricted the problem to the static and axisymmetric case. However, accreting astrophysical systems tend to rotate rapidly, so it is desirable to release the staticity restriction and extend to the stationary setting. Interestingly, several studies already made in the literature indicate that rotational dragging might attenuate the geodesic chaos. We plan to check this observation using the metric describing the linear perturbation of Schwarzschild due to a rotating light finite thin disc [2]. A related problem might also be studied whether the chaos observed is not mainly induced by crossings of the (thin, thus non-smooth) disc by the geodesics. Still another possibility would be to employ another methods (not yet considered), as e.g. the one based on the analysis of the character of “basin boundaries”. Finally, more analytical work could be done on the perturbation metric itself, mainly the latter should be compared with other solutions describing black holes surrounded by matter. |
doc. Mgr. Tomáš Ledvinka, Ph.D. | 6 |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Petr Lukeš |
Study of some aspects of AdS/CFT correspondence in 2+1 dimensions
|
Study of some aspects of AdS/CFT correspondence in 2+1 dimensionsCílem práce je studium souvislosti entangement entropie s velikostí extremální nadplochy v rámci AdS/CFT korespondence ve zjednodušeném 2+1 dimenzionálním modelu. |
prof. RNDr. Krtouš Pavel, Ph.D. | 7 |
| name | PhD thesis | abstract | Supervisor / Consultant | Year |
| Jiří Černý |
Canonical quantization of black hole spacetimes
|
Canonical quantization of black hole spacetimesStudent se seznámí s několika přístupy ke kanonickému kvantování prostoročasů. Jednat se bude zejména o metodu založenou na Wheelerově-deWittově rovnici, dále o její modifikaci vycházející z použití symetrií superprostoru na kvantové úrovni a následně o smyčkové metody kvantování v rámci sférické symetrie. Rozšíření za rámec sférické symetrie může být provedeno hybridním kvantováním, kdy se stupně volnosti popisující odchylku od symetrické situace řeší pomocí Fockova kvantování. |
RNDr. Otakar Svítek, Ph.D. | 8 |
Graduates
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
|---|---|---|---|---|
| Aleš Flandera |
Classical and quantum effects in the neighborhood of isolated horizons
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Classical and quantum effects in the neighborhood of isolated horizonsNáplní doktorské práce bude podrobné studium klasických a kvantových jevů v obecné relativitě. Student se detailně seznámí s existující literaturou na téma izolovaných horizontů, což je koncept černých děr v rovnováze s okolím, který zobecňuje klasická řešení jako je Schwarzschildovo nebo Kerrovo řešení. Na klasické úrovni, se bude jednat zejména o studium trojrozměrné geometrie těchto horizontů, výpočet kvazi-lokálních multipólových momentů izolovaných horizontů a jejich vztah k standardním Geroch-Hansenovým multipólům. Za tímto účelem si student studiem literatury prohloubí znalosti diferenciální geometrie, zejména Cartanův formalismus a formalismus Newmanův-Penroseův a teorii fibrovaných variet. Kvantové efekty na klasickém pozadí standardních černých děr byly v minulosti podrobně prozkoumány a existuje k nim rozsáhlá literatura. Student se primárně seznámí se standardními výsledky kvantové teorie pole na křivém pozadí, jako je Hawkingův a Unruhův efekt, a kreace částic v kosmologických modelech. Bude se také věnovat studiu rigoróznější formulace kvantové teorie pole a vlastností Bogoľubovovy transformace, algebraické kvantové teorii pole a bezsouřadnicové formulaci teorie pole. Seznámí se také s použitím WKB aproximace vedoucí k částicové interpretaci Hawkingova a Unruhova jevu. Cílem práce je zobecnit některé z těchto výsledků na případ prostoročasů kolem izolovaných horizontů. - Analýza možnosti zobecnění harmonických funkcí se spinovou váhou pro topologické sféry generující horizont. - Řešení vlnové rovnice (Klein-Gordonovy, ale i pro vyšší spiny) v okolí izolovaného horizontu pomocí sférických harmonických funkcí. - Formulace Kerrova-Newmanova (KN) prostoročasu jako charakteristického počátečního problému s evolucí podél netwistující nulové kongruence a studium perturbací KN prostoročasu v tomto formalismu. Diskuse globálního rozšíření souřadnicového systému použitého v práci [BK]. - Analýza elektromagnetických polí v okolí izolovaných horizontů. Formulace vhodných okrajových a počátečních podmínek pro zvolené typy polí: asymptoticky homogenní pole, dipól v blízkosti horizontu. Numerické řešení rovnic pole a aplikace výsledků na Meissnerův efekt [GS]. - Reformulace a zobecnění existující práce [XWSG], která používá WKB aproximaci aplikovanou na izolovaný horizont. Zobecnění zahrnuje opuštění WKB aproximace, nalezení příslušné Bogoľubovovy transformace a výpočet středního počtu emitovaných částic. - Analýza možného zobecnění modelu [CGHS] pro vypařující se černou díru na případ izolovaných horizontů. |
doc. Mgr. Tomáš Ledvinka, Ph.D. | 2026 |
| Jiří Táborský |
Low energy reactive collisions in negatively charged triatomic systems.
|
Low energy reactive collisions in negatively charged triatomic systems.Theoretical description of electron-molecule collisions still represents a great challenge. This problem is closely related to the theory of reactive collisions of negative ions. In addition to involving many particles, this theory is complicated by the contribution of electron continuum and breakage of the Born-Oppenheimer approximation. All these problems are properly solved in the nonlocal resonance model theory. This theory is used only for diatomic molecules. For triatomic molecules the theory has been used only in the local complex potential approximation [5]. Goal of this work is to contribute to the solution of triatomic collisions beyond the Born-Oppenheimer approximation. |
doc. RNDr. Martin Čížek, Ph.D. | 2026 |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Jakub Cehula |
Theory of binary star interactions
|
Theory of binary star interactionsThis thesis is focused on advancing the theory of binary star interactions. The immediate goal is to revisit the prescriptions for mass transfer in close binaries and investigate their influence on runaway phases of binary star evolution culminating in common envelope events. This evolutionary pathway is of great importance for producing many important astrophysical objects, including gravitational wave sources like binary black holes and double neutron stars. Depending on the interest of the student, this work will be extended and followed up with additional projects in single and binary star evolution or theoretical astrophysics in general. The tools of choice will be analytic and semi-analytic models, 1D stellar evolution calculations, numerical hydrodynamics potentially including radiation or magnetic fields, or N-body calculations. Participation in modeling of data, especially from the All-Sky Automated Survey for Supernovae, is possible. |
doc. Mgr. Ondřej Pejcha, Ph.D. | 2025 |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Václav Alt | doc. RNDr. Karel Houfek, Ph.D. | 2024 | ||
| Barbora Bezděková |
Propagation and transfer of electromagnetic radiation in refractive and dispersive media in relativistic spacetimesOd začátku práce na disertaci studovat níže doporučenou a sledovat nově se objevující literaturu. V původní práci se nejprve v rámci speciální teorie relativity zaměřit na "vrstevnatá" prostředí, která se pohybují s měnící se velikostí rychlosti ve stejném směru a šíření záření dopadajícího v kolmém směru na tyto vrstvy. Prostředí má jak refraktivní tak disperzivní vlastnosti. Zobecnit úlohu i na diferenciálně rotující prostředí. Vhodně vykreslit trajektorie paprsků pro různé rychlosti prostředí, zkoumat limitní případy relativistických rychlostí. V další fázi práce se věnovat šíření záření v prostředí kolem černých děr, zvláště kolem rotující (Kerrovy) černé díry (viz např.[3,4,10]). Zjistit oblasti dostupné pro paprsky v různých prostředích v černoděrových prostoročasech. Zkoumat problematiku šíření vln v protředí v případě černých děr (či jiných kompaktních objektů)i v kosmologickém kontextu (bez předpokladu asymptotické plochosti) a v kontextu gravitačních čoček (viz [5,6, 8,9,10]). Za výchozí základní formalismus uvažovat Hamiltonovskou teorii paprsků v prostředí v obecném prostoročase založenou na limitě geometrické optiky (viz [1,2,3]). Ta vychází z předpokladu velmi vysokých (v limitě nekonečných) frekvencí světla. V posledních několika letech se objevily studie [7] vyšetřující gravitační spinový Hallův efekt, v němž dynamika paprsků je ovlivněna polarizací světla a vychází tak za rámec geometrické optiky. Zkusit vytvořit modelové situace, v nichž se efekt projeví. |
prof. RNDr. Jiří Bičák, DrSc., dr. h. c.; doc. Mgr. David Heyrovský, AM Ph.D. | 2024 | |
| Petr Kotlařík |
Gravitational sources in the vicinity of black holesNedávno zveřejněný "snímek" černé díry v jádře galaxie M87 potvrdil, že možnosti detektorů se rozšířily na samotné hranice (horizonty) těchto extrémních objektů. Díky robustnosti obecně relativistické předpovědi nebylo překvapením, že jí publikovaný obrázek velmi dobře odpovídá, nicméně snaha o zpřesnění observačních dat bude dále pokračovat, aby bylo možno kvantifikovat, do jaké míry odpovídají podobné objekty černým dírám popsaným Kerrovým řešením, a určit jejich parametry. Reálné černé díry rozhodně neodpovídají Kerrovu řešení přesně, poněvadž toto řešení popisuje černé díry izolované ("vakuové"), stacionární a existující v asymptoticky plochém prostoročasu. Je proto zajímavé odhadovat, jak by se měly od kerrovského ideálu lišit a jaké by to mělo mít observační důsledky. Hlavním důvodem těchto odchylek by měla být hmota (látka a pole) přítomná v okolí černé díry (jen díky ní lze ostatně černou díru v oboru elektromagnetického záření odhalit). V této práci budeme zkoumat různé zjednodušené konfigurace hmoty v blízkosti černých děr a posuzovat, jaký vliv má jejich gravitace na vlastnosti prostoročasu a samotných černých děr. Bez ohledu na astrofyzikální motivaci je téma zajímavé i čistě teoreticky, neboť Einsteinovy rovnice jsou nelineární, takže "superpozice" gravitace černých děr s gravitací dodatečných zdrojů může přinést i ne zcela očekávané výsledky. |
doc. RNDr. Oldřich Semerák, Ph.D., DSc. | 2024 | |
| Camille Flore Marie Landri |
Theory and observations of two stars undergoing strong interaction or mergerThe goal of the thesis is to significantly develop understanding of the theory and observational implications of two stars undergoing strong interaction or a merger. Depending on the interests of the student, the work will focus on understanding unusual transients likely associated with binary star interactions, transients from stellar collisions, formation of dust and molecules in binary interactions, and understanding the observational implications of the theory (blue stragglers, R CrB stars, FK Com stars, eta Car, progenitor of SN1987A, etc.). In addition to analytic or semi-analytic work, the thesis can utilize existing codes or codes under development in the group: 1D stellar evolution, smoothed particle (radiation)hydrodynamics, moving mesh radiation hydrodynamics, or N-body calculations. In addition, the group is a member of All-Sky Automated Survey for Supernovae (ASAS-SN), and the thesis can include significant observational or data analysis component from ASAS-SN or other photometric or spectroscopic surveys (APOGEE, Gaia, TESS). |
doc. Mgr. Ondřej Pejcha, Ph.D. | 2024 | |
| Marek Liška |
Thermodynamics of spacetime: corrections from the quantum realm
|
Thermodynamics of spacetime: corrections from the quantum realmThermodynamics of spacetime. |
Ana Alonso Serrano, Ph.D. / doc. RNDr. Oldřich Semerák, Ph.D., DSc. | 2024 |
| Milan Pešta |
Illuminating binary star evolution with observed populations and theoretical modelingWith the discovery of gravitational waves from merging compact object binaries and the associated electromagnetic signatures there has been renewed interest in properly understanding and characterizing binary star evolution and especially its violent phases such as common envelope evolution. At the same time, astronomy has witnessed a tremendous growth of available data thanks to dedicated time-domain surveys. The goal of this project is to provide novel constraints on the critical binary star evolutionary phases on the interface of complex data modeling and theoretical inquiry. |
doc. Mgr. Ondřej Pejcha, Ph.D. | 2024 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Michal Karamazov |
Gravitational Lensing by Substructures in Dark Matter HalosGravitational lensing serves as an invaluable tool for studying the distribution of mat- ter in the universe. This matter is predominantly dark and clumped into centrally concen- trated hierarchically structured halos of galaxies and galaxy clusters. Early comparisons suggested discrepancies between the high population of substructures predicted by cos- mological simulations and the lack of corresponding observational data. More recently, a major discrepancy in the opposite sense was reported from analyses of lensing galaxy clusters: the lensing efficiency of their substructures was found to be much higher than predictions based on cosmological simulations. In this thesis, we examine gravitational lensing by substructures embedded in dark-matter halos with Navarro-Frenk-White (NFW) density profiles. We start by a detailed investigation of a simple model with a single point mass perturbing the halo. Using analytical methods, we study its critical curves, caustics and their transitions. Next, we explore the geometry of lensed images and the weak-lensing characteristics of the same simple model, developing novel ways of their visualization. Finally, we construct a more realistic lens model of a galaxy cluster con- sisting of an ellipsoidal cluster halo combined with a population of truncated ellipsoidal galaxy... |
doc. Mgr. David Heyrovský, AM Ph.D. | 2023 | |
| Lukáš Polcar |
Weyl metrics and their generalizations: classical and quantum viewpointIn this thesis, we study two distinct topics both connected to stationary axially sym- metric spacetimes. The first is a study of an exact solution sourced by phantom scalar field. This solution can be derived from the well-known Curzon-Chazy metric and has several unusual features. It is a spherically symmetric wormhole which is however not symmetric with respect to its throat, it possesses a non-scalar curvature singularity and functions as a one-directional time machine. The energy content of the spacetime is ex- amined and various other properties are discussed. The remaining parts are dedicated to extreme mass ratio inspirals in two stationary axially symmetric spacetimes, perturbed Schwarzschild and Kerr. The canonical perturbation theory was used to transform the respective geodesic Hamiltonian to action-angle coordinates allowing us to evolve flux- driven inspirals in both spacetimes. |
RNDr. Otakar Svítek, Ph.D. | 2023 | |
| Viktor Skoupý |
Gravitational wave templates from Extreme Mass Ratio Inspirals.Future space-based gravitational-wave detectors will require highly accurate gravi- tational wave templates for detecting extreme mass ratio inspirals and estimating their parameters. These templates must include the postadiabatic effects like the spin of the secondary body. Therefore, we investigate the influence of the secondary spin on the motion around a Kerr black hole, calculate the corresponding gravitational-wave fluxes to produce flux-driven inspirals and reveal the shifts of the gravitational-wave phases induced by the secondary's spin. In particular, this study begins by considering eccentric equatorial orbits, where we obtain the constants of motion and fundamental frequen- cies using the Mathisson-Papapetrou-Dixon equations. Next, we derive the linear-in-spin parts of these quantities. We introduce a new Teukolsky equation solver in the frequency domain to calculate the energy and angular momentum fluxes from these trajectories. We use the obtained fluxes to adiabatically evolve the orbital parameters and to find the spin-induced phase shifts. For off-equatorial orbits, a frequency-domain approach is employed to determine the trajectories in the linear-in-spin regime and to compute the re- spective fluxes. The agreement between the frequency-domain fluxes and those acquired using an existing... |
Georgios Loukes Gerakopoulos, Ph.D. / doc. Mgr. Tomáš Ledvinka, Ph.D. | 2023 | |
| Adam Vrátný |
Spacetimes with black holesIn this thesis, we study exact black hole spacetimes of algebraic type D, which are a part of much wider Pleba'nski-Demia'nski class of solutions. We reformulate the well- known form of this metric and obtain new improved representation of this black hole family with simplified, explicit and (at least partially) factorized metric functions. This new form of the spacetimes allows us to gain the standard expressions for the well-known solutions such as the Kerr-Newman-NUT-(anti-)de Sitter black hole, accelerating Kerr- Newman-(anti-)de Sitter black hole, (possibly charged) Taub-NUT-(anti-)de Sitter black hole, accelerating Kerr-NUT-(anti-)de Sitter black hole, and their special cases in asymp- totically flat universe, just by putting the appropriate parameters to zero. We also provide a thorough physical and geometrical analysis of this new form of spacetimes. Furthermore, we analyze a solution corresponding to the accelerating Taub-NUT black hole, which was originally found by Chng, Mann and Stelea in 2006. We perform an in-depth analysis of this solution, and study its relation to the Pleba'nski-Demia'nski class. |
prof. RNDr. Jiří Podolský, CSc., DSc. | 2023 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Jan Dvořák |
Contribution to theory of low-energy electron-molecule collisionsCollisions of low-energy electrons with molecules lead to excitation of vibrational degrees of freedom or even to bond dissociation. Such phenomena are not fully understood in the case of polyatomic targets since the theoretical treatment is complicated by the multidimensionality of the vibrational dynamics and the interaction of multiple short- lived electronic states. In this thesis, we extend the nonlocal theory of these processes by considering the vibronic coupling through the electron continuum. In particular, we study vibrational excitation of carbon dioxide and dissociation of the N-H bond of pyrrole. For carbon dioxide, the dynamics includes all vibrational modes and three electronic states. The model explains the long-time puzzling shape of the observed energy-loss spectra as well as the origin of a fine structure revealed in a recent experiment. In the case of pyrrole, we study the effect of the motion of distant parts of the molecule on the dissociation. |
doc. RNDr. Martin Čížek, Ph.D. | 2022 | |
| Anton Khirnov |
Representation of dynamical black hole spacetimes in numerical simulationsChoptuik's unexpected discovery, almost 30 years ago, of critical behavior in grav- itational collapse opened a whole new research area within numerical relativity. While critical collapse in spherical symmetry has been thoroughly investigated and is reasonably well understood, progress for axial symmetry has been much slower. In this thesis, we study axially symmetric gravitational collapse of gravi- tational waves using numerical simulations. We construct several very different initial data families and investigate their behavior close to the threshold of collapse. We compare them against each other and also against other published results. We use invariant quantities to look for signs of self-similarity and universality. |
doc. Mgr. Tomáš Ledvinka, Ph.D. | 2022 | |
| Eliška Polášková |
Properties and interpretation of black hole spacetimesIn this thesis, we study a limit of the Kerr-(A)dS spacetime in a general dimen- sion where an arbitrary number of its rotational parameters is set equal. The resulting metric after the limit formally splits into two parts: the first part has the form of the Kerr-NUT-(A)dS metric analogous to the metric of the entire spacetime, but only for the directions not subjected to the limit, and the second part can be interpreted as the Kähler metrics. However, this separation is only valid for tangent spaces and it is not integrable, thus it does not lead to independent manifolds. We also reconstruct the origi- nal number of explicit and hidden symmetries associated with Killing vectors and Killing tensors. Therefore, the resulting spacetime represents a special case of the generalized Kerr-NUT-(A)dS metric studied before that also retains the full Killing tower of sym- metries. In D = 6, we present evidence of an enhanced symmetry structure after the limit. Namely, we find additional Killing vectors and show that one of the Killing tensors becomes reducible as it can be decomposed into Killing vectors |
prof. RNDr. Pavel Krtouš, Ph.D. | 2022 | |
| Jiří Veselý |
Exact spacetimes and their physical propertiesMotivated by our desire to find generalizations of the Bonnor-Melvin spacetime, the thesis investigates seven static, cylindrically-symmetric and electrovacuum exact solutions to the Einstein-Maxwell equations. They contain a magnetic field and six of them also include the cosmological constant. After discussing some of the methods we use during our investigation, we present the basic properties of the spacetimes, and for each of them we also study charged test particle motion and their admissible shell sources composed of particle streams. We also perform numerical computations to determine whether the equations admit more general solutions than the exact ones we derived. |
doc. RNDr. Martin Žofka, Ph.D. | 2022 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Morteza Kerachian |
Selected problems in relativistic cosmology
|
Selected problems in relativistic cosmologyIn this work, we studied three selected problems in FRW spacetime. In the first part, we analysed the motion of a test particle in the homogeneous and isotropic universe. We presented a framework in which one can derive the uniformly accelerated trajectory and geodesic motion if a scale factor for a given spacetime is provided as a function of coordinate time. By applying the confomal time transformation, we were able to convert second order differential equations of motion in FRW spacetime to first order differential equations. From this, we managed to obtain a formalism to derive the uniformly accelerated trajectory of a test particle in spatially curved FRW spacetime. The second part of this work is devoted to dynamical cosmology. In particular, we analyse the cases of barotropic fluids and non-minimally coupled scalar field in spatially curved FRW spacetime. First, we set up the dynamical systems for an unspecified EoS of a barotropic fluid case and an unspecified positive potential for a non-minimal coupled scalar field case. For both of these systems, we determined well-defined dynamical variables valid for all curvatures. In the framework of these general setups we discovered several characteristic features of the systems, such as invariant subsets, symmetries, critical points and their... |
prof. RNDr. Jiří Bičák, DrSc., dr. h. c. / prof. RNDr. Pavel Krtouš, Ph.D. | 2020 |
| Jiří Ryzner |
Selected exact spacetimes in Einstein's gravityThe aim of this thesis is to construct exact, axially symmetric solutions of Einstein- Maxwell(-dilaton) equations, which possess a discrete translational symmetry along an axis. We present two possible approaches to their construction. The first one is to solve Einstein-Maxwell equations, the second one relies on a dimensional reduction from a higher dimension. We examine the geometry of the solutions, their horizons and singu- larities, motions of charged test particles and compare them. |
doc. RNDr. Martin Žofka, Ph.D. | 2020 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Ondřej Hruška |
Investigation of geometrical and physical properties of exact spacetimesIn this work, we study geometrical and physical properties of exact spacetimes that belong to non-expanding Pleba'nski-Demia'nski class. It is a family of solutions of type D that also belong to the Kundt class, and contain seven arbitrary parameters including a cosmological constant. We present here the results of three extensive articles, each focusing on a different aspect of the problem. In the first article, we investigate the meaning of individual parame- ters in the non-expanding Pleba'nski-Demia'nski metric. First, we set almost all parameters to zero and obtain Minkowski and (anti-)de Sitter backgrounds. Af- terwards, we allow other parameters to be non-zero and we study the B-metrics, non-singular "anti-NUT" solutions and conclude with the full electrovacuum Pleba'nski-Demia'nski metric. In the second article, we focus on the de Sitter and anti-de Sitter backgrounds where we present and analyse 11 new diagonal metric forms of (anti-)de Sitter spacetime. We find five-dimensional parametriza- tions, draw coordinate surfaces and conformal diagrams. In the third article, we show that the AII-metric together with the BI-metric describes gravitational field around a tachyon on both Minkowski and (anti-)de Sitter backgrounds. Finally, in order to better understand the global structure and... |
prof. RNDr. Jiří Podolský, CSc., DSc. | 2019 | |
| Ivan Kolář |
Spacetimes with symmetries in a general dimensionIn this work we study properties of spacetimes with a high degree of symme- try. Particularly, we focus on geometries related to higher-dimensional rotating black-hole spacetimes described by the Kerr-NUT-(A)dS metric. In the first part, we examine spacetimes admitting a separable Klein-Gordon equation. Motivated by Carter's work in four dimensions, we introduce a separable met- ric ansatz in higher dimensions. Analyzing Einstein's equations, we obtain the Kerr-NUT-(A)dS and specific Einstein-K¨ahler metrics. Then we consider a metric ansatz in the form of warped geometries of two Klein-Gordon separable metrics and classify the corresponding solutions. In the second part, we in- vestigate a class of limits of the Kerr-NUT-(A)dS spacetimes where particular roots of metric functions degenerate. Our limiting procedure results in various NUT-like and near-horizon geometries such as the higher-dimensional Taub- NUT-(A)dS spacetime. We demonstrate that the symmetries of the resulting geometries are enhanced, which is manifested by decomposition of Killing ten- sors into Killing vectors. The third part of this work deals with generalized symmetry axes of the Kerr-NUT-(A)dS spacetimes that are formed by fixed points of isometries. We show that some parts of the symmetry axes are sin- gular for nonzero NUT charges.... |
prof. RNDr. Pavel Krtouš, Ph.D. | 2019 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Josef Schmidt |
Conserved quantities in theories of gravity: two selected problems
|
prof. RNDr. Jiří Bičák, DrSc., dr.h.c. | 2018 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Jakub Benda |
Astrophysically important processes in collisions of electrons with hydrogen atomsAstrophysically important processes in collisions of electrons with hydrogen atoms This thesis focuses on calculations of the cross sections and other scattering quantities that characterize the outcome of collisions of electrons with hydro- gen atoms. For the chosen energy range and atomic transitions the scattering process is solved within the non-relativistic quantum mechanics by discretiz- ation of the Schr¨odinger equation in the basis of B-splines, which transforms the equation into a linear-algebraic problem. The thesis discusses the boundary conditions, methods of solution of the linear system, preconditioning of the sys- tem and interpretation of results, including several original ideas that proved to be very beneficient for the calculations. The calculated data are provided by means of graphs at the end of the thesis. Also, a custom web-based scattering database containing the results has been set up, freely available to the expected audience of this project. |
doc. RNDr. Karel Houfek, Ph.D. | 2017 | |
| Pavel Čížek | doc. RNDr. Oldřich Semerák, Ph.D., DSc. | 2017 | ||
| Martin Váňa | doc. RNDr. Karel Houfek, Ph.D. | 2017 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Kamil Daněk |
Triple gravitational microlensCílem práce je 1) podat ucelený přehled topologií kritických křivek a kaustik trojité gravitační mikročočky; 2) prozkoumat chování mapy zjasnění v blízkosti jednotlivých částí kaustiky; 3) studovat zjasnění nebodového zdroje, citlivost čočky na nebodovost a okrajové ztemnění zdroje; 4) uplatnit zjištěné výsledky na pozorovaných případech trojitých mikročoček. |
doc. Mgr. David Heyrovský, AM Ph.D. | 2015 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Jiří Eliášek | doc. RNDr. Martin Čížek, Ph.D. | 2014 | ||
| Petr Kašpar |
Inhomogeneous cosmology and averaging methodsPodrobně rozebrat a porovnat různé způsoby středování používané v nehomogenních kosmologických modelech a pro vysvětlení různých astrofyzikálních jevů (např. galaktických rotačních křivek). Dokončit vývoj středovacího postupu navrženého v rámci diplomové práce a aplikovat ho v zajímavých netriviálních situacích. Pokusit se použít programy pro algebraické manipulace ke zjednodušení výpočtů s Cartanovými skaláry, na kterých je vyvýjená metoda založena. Prostudovat vazbu středování nehomogenit na astrofyzikální efekty standardně vysvětlované pomocí temné hmoty a temné energie. Prozkoumat generování symetrií původně obecného nehomogenního prostoročasu při specifickém středování. |
RNDr. Otakar Svítek, Ph.D. | 2014 | |
| David Vrba | RNDr. Otakar Svítek, Ph.D. | 2014 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Marián Pilc |
Model problems of the theory of gravitation
|
prof. RNDr. Jiří Bičák, DrSc., dr. h. c. | 2013 | |
| Petra Suková | doc. RNDr. Oldřich Semerák, Ph.D., DSc. | 2013 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Jakub Hruška | doc. RNDr. Martin Žofka, Ph.D. | 2012 | ||
| Robert Švarc | prof. RNDr. Jiří Podolský, CSc., DSc. | 2012 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Jindřich Dolanský |
Time machines
|
doc. RNDr. Jiří Langer, CSc. | 2011 | |
| Norman Gürlebeck |
Solutions Generating Techniques in Field Theories
|
prof. RNDr. Jiří Bičák, DrSc., dr.h.c. | 2011 | |
| Martin Scholtz |
Problems of radiation in relatistic field theories
|
prof. RNDr. Jiří Bičák, DrSc., dr.h.c. | 2011 | |
| Miroslav Šulc | prof. RNDr. Jiří Horáček, DrSc. | 2011 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Hedvika Kadlecová | prof. RNDr. Pavel Krtouš, Ph.D. | 2010 | ||
| Ivan Pshenichnyuk | doc. RNDr. Martin Čížek, Ph.D. | 2010 | ||
| Pavel Sládek | prof. RNDr. Pavel Krtouš, Ph.D. | 2010 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| David Kofroň |
Exact and perturbed models in relativistic theories
|
prof. RNDr. Jiří Bičák, DrSc., dr.h.c. | 2009 | |
| Michal Tarana | prof. RNDr. Jiří Horáček, DrSc. | 2009 | ||
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Miroslav Beláň |
Exact radiative solutions in Einstein theory
|
prof. RNDr. Jiří Podolský, CSc., DSc. | 2005 | |
| Přemysl Kolorenč |
Energy transfers in small molecules
|
prof. RNDr. Jiří Horáček, DrSc. | 2005 | |
| Otakar Svítek |
Gravitational waves: approximate methods and exact solutions
|
prof. RNDr. Jiří Podolský, CSc., DSc. | 2005 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Karel Houfek |
Cross sections and rate constants of resonant low-energy electron-molecule collisions
|
prof. RNDr. Jiří Horáček, DrSc. | 2002 | |
| Martin Žofka |
On cylindrical, spherical, and disk sources in general relativity
|
prof. RNDr. Jiří Bičák, DrSc., dr. h. c. | 2002 | |
| name | PhD thesis | abstract | Supervisor / Consultant | Graduation year |
| Tomáš Doležel |
Couches minces et branes en cosmologie et leurs perturbations
|
prof. RNDr. Jiří Bičák, DrSc., dr.h.c. / N. Deruelle | 2001 | |
| Karel Veselý |
Gravitační pp-vlny
|
prof. RNDr. Jiří Podolský, CSc., DSc. | 2001 |
