Phd Disertation Themes

Institute of Physics offers several PhD positions every year in a few doctoral degree programs. Possible topics for Your study can be found below. As a first step, it is best to contact the potential supervisor who will provide you with the most qualified answers to the topic, tasks and position requirements.

Study year 2023/24

  1. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    Tensor product states represent a modern mathematical language that accurately approximates quantum states. As a typical example, we can consider systems of interacting fermions or bosons, which are specified by Hamiltonian. We will focus on the description of magnetic properties, for which the model of interacting spins is sufficient. We understand by it the common properties between fermionic and boson particles. A quantum tensor-product state carries not only the physical degrees of freedom describing the parts but also so-called auxiliary (non-physical) degrees of freedom that control the reach of correlations and quantum entanglement. As the number of auxiliary degrees of freedom increases, so does the numerical accuracy. During the PhD studies, we will characterize many-body interacting systems using the quantum entanglement entropy and standard observables. We focus on the analysis of critical properties of spin systems that include non-trivial properties with different topological phases. Since these systems are not exactly solvable, we develop novel numerical procedures using a suitable programming language, e.g. Python, MatLab, C++, etc. The goal is to propose new, alternative methods of tensor networks, which originate in renormalization techniques. We intend to analyze fractal structures and hyperbolic curved geometry, related to the theory of quantum gravity.
    Contact: andrej.gendiar@savba.sk
  2. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    The intersection of quantum information and gravity is a rapidly developing research field, in which we use the tools of quantum information to investigate new phenomena that may be experimentally realized in the interplay of quantum physics and gravity. Nowadays, there are fast advancements of experimental techniques, including those in the fields of cold atoms and quantum optics, also performed in spatial missions, and they have opened new opportunities to explore areas that are not tested yet. On one hand, we base our research on the current technology to theoretically identify new effects that can be measured in the interplay of quantum physics and gravity. On another hand, it is connected with philosophy, as proposing a consistent experiment requires addressing fundamental questions such as “what is time?” or “what is a measurement?”. A background in quantum information, quantum field theory or general relativity is desirable.
    Contact: mario.ziman@savba.sk
  3. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    A background in photonics sciences like nonlinear optics, lasers, light propagation in complex medium and/or in material sciences like the physics of semiconductors, nanostructure, photodiodes is strongly recommended. The candidate will need to also be familiar with basic computer sciences in order to perform simulation of physical systems, control of instrumentation and custom design software for post-processing of experimental data. A candidate which is strongly motivated, independent, rigorous and organised with only some of these skills will find the perfect environment to gain the rest of them during his PhD. The subject is part of European project aiming to build quantum communication infrastructure (quantum network) in Slovakia. Student will be participating directly on this project.
    Contact: djeylan.aktas@savba.sk
  4. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    Quantum network are currently being realized worldwide including Slovakia. There are several related theoretical and practical research problems: design of verification methods, certification of desired properties, management of the transfered quantum packets, etc. Within the scope of the PhD thesis the EU should be covered by working quantum network and it is the task of PhD students to participate and design protocols and propose experiments that are going to be run on such infrastructure.
    Contact: mario.ziman@savba.sk
  5. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    he problems addressed by quantum technologies motivated development of new mathematical tools and structures collected under the umrella of higher-order structures. They enables us to shift from studies of quantum systems to analysis of quantum dynamics, measurements and also more mythical structures as indefinite causality and memory channels. The community working in this foundational area is quickly growing and covering many interesting subjects - machine learning, resource theories, foundations of thermodynamics, etc. The particular task will be specified in discussion and will depend on personal preferences of the student and currently running research projects.
    Contact: michal.sedlak@savba.sk
  6. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    NISQ (Noisy intermediate-scale quantum) computers are quantum computers available today that contain tens to a few hundred qubits, can execute a protocol with a depth of a few tens of steps, and are heavily influenced by errors and noise. We will develop and test algorithms applicable on such computers.
    Contact: martin.plesch@savba.sk
  7. Study program:
    Physics of Condensed Matter and Acoustics / FMFI UK
    Annotation:
    The aim of the dissertation is to propose, and investigate effective theoretical models suitable for the phenomenological description of transport and relaxation phenomena in one- and two-dimensional superconductors. Plus, to demonstrate their applicability in specific situations defined by experiments ongoing at the University of Regensburg: a) magneto-transport measurements for anti-dot arrays (Prof. Dr. Dieter Weiss' group), b) superconducting magneto-chiral and magneto-rectification effects in non-centrosymmetric superconductors (Prof. Dr. Christoph Strunk's group). The specific objectives of the project are to investigate the dynamics and formation of bound and resonant states at material interfaces depending on the type and topology of the pair interaction, temperature, influence of (in)ordering, etc. Along with that, also to analyze the behavior of the superconducting ordering parameter by solving the Ginzburg Landau equations with the so-called Lifshitz invariants, namely for bulge quasi-2D systems and Josephson junctions.
    Contact: denis.kochan@savba.sk
  8. Study program:
    Physics of Condensed Matter and Acoustics / FMFI UK
    Annotation:
    Experimentally, alloys containing phases with complex structures are out of equilibrium at low temperatures, due to the vanishing atomic diffusion rates. Ground states of such systems can be reconstructed by modelling and simulations. We will use density functional theory (DFT) package in machine-learning force-field mode combined with replica exchange method to reveal so far unobserved complex ground state structures in binary Al-Mn, Mg-Zn and Sc-Zn alloys, and their ternary extension Al-Mn-Pd, Mg-Zn-Al, and Sc-Zn-Mg.
    Contact: marek.mihalkovic@savba.sk
  9. Study program:
    Nuclear and Subnuclear Physics / FMFI UK
    Annotation:
    The free volume properties of polymer networks of selected model materials from the methacrylate group, which will be prepared by polymerization at high pressures, will be investigated. The local free volume will be studied by using a positronium probe and measuring its lifetime at the annihilation site by positron annihilation lifetime spectroscopy (PALS) technique. The positron source will be the radioisotope 22Na. Based on the data experimentally obtained by the PALS technique and appropriate models for the conversion of orthopositronium lifetimes to the size of free-volume cavities, the properties of the network (thermal expansion coefficients, glass transition temperature Tg, sub-Tg transitions, spatial homogeneity of the network) will be characterized. Changes in crosslinking, compared to classically prepared materials under laboratory conditions, and improved material properties are expected. The degree of double bond conversion by near infrared spectroscopy (NIR) and surface structure by scanning electron microscopy (SEM) will also be monitored. Methacrylates have versatile applications in various fields (dental materials, 3D printing materials, protective coatings). Funding for the PhD experiments will be from the project APVV-21-0335, project duration: 2022-2026
    Contact: ondrej.sausa@savba.sk
  10. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    The topic will be focused on the bioconjugation of 2D materials and their application in photothermal cancer treatment. We have recently demonstrated that suitably bioconjugated 2D materials can have increased selectivity towards cancer cells, which is generally an important step to overcome the difficulties of currently in use cancer treatments. Photothermal therapy triggered by irradiation of bioconjugated 2D materials can offer a breakthrough solution in the currently available therapies. The work will encompass – detailed characterization of cells and tissues via confocal Raman microspectroscopy, contribution to the preparation of nanostructures exhibiting photothermal properties, research and design of the bioconjugation of 2D photothermal nanomaterials (MoOx, MXene), in vitro and ex ovo studies with bioconjugated nanostructures, localization studies via confocal Raman microspectroscopy and complementary techniques (flow cytometry, confocal laser scanning microscopy) and optimization of the measurement conditions for different cell lines. The work will be realized at the Institute of Physics SAS. For detailed information, please contact adriana.annusova@savba.sk
    References:
    1. Liu, S et al., Two‐Dimensional Nanomaterials for Photothermal Therapy, in Angewandte Chemie 132, 5943-5953 (2020), 2. Kálosi, A. et al., A bioconjugated MoS2 based nanoplatform with increased binding efficiency to cancer cells, in Biomater. Sci. 8, 1973–1980 (2020)
    Contact: adriana.annusova@savba.sk
  11. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    In the last decade, hybrid organic-inorganic perovskites have become the main candidates for efficient photodiodes and next-generation solar cells. Due to their high photoluminescence quantum yields (PLQY), hybrid perovskites efficiently convert injected charge carriers into light and vice versa. Although the PLQY is relatively high, further efficiency enhancement is limited by non-radiative recombination - either recombination at defects in the absorber layer or recombination of minority carriers at the perovskite-transport layer interface. The scope of this work will be to study the defects that play a crucial role in limiting the performance of photovoltaic devices and the development of efficient passivation pathways to advance efficiency further. For this purpose, optical spectroscopy methods (photoluminescence, absorbance, scanning optical microscopy) and indirect scattering methods (X-ray diffraction) will be used. The work will be carried out at the Institute of Physics of the Slovak Academy of Sciences. For detailed information, please email to: nada.mrkyvkova@savba.sk.
    Contact: nada.mrkyvkova@savba.sk
  12. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    Anode-free solid-state batteries are currently the focus of research, as they will offer high capacity combined with improved safety due to the solid-state electrolyte. However, the question of the best design in terms of structure and materials is still open. The PhD study will focus on unraveling the residual stress in solid-state batteries and its evolution during charging and discharging. In particular, we will focus on an anode-free design with no excess lithium and track the stress by X-ray and Raman scattering. The work will be carried out in collaboration with a consortium of partners from Spain, France, Norway, Austria, UK, and Germany under the EU Horizon project OPERA. The work will be carried out at the SAS Institute of Physics and at several European synchrotron facilities, including Hamburg (DESY, DE) and Grenoble (ESRF, FR). For detailed information, email: peter.siffalovic@savba.sk.
    References:
    Huang et al. Anode-Free Solid-State Lithium Batteries. Advanced Energy Materials, 12 (26), 2022, 2201044, doi 10.1002/aenm.202201044.
    Contact: peter.siffalovic@savba.sk
  13. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    he topic will be focused on the applications of nanomaterials for advanced biomedical systems. We have recently demonstrated that suitably bioconjugated nanomaterials can have increased selectivity towards cancer cells, which is generally an important step to overcome the difficulties of currently in use cancer treatments. Moreover, the nanomaterials can be tuned to have special functions, such as they can be utilized in photothermal therapy. Photothermal therapy induced by irradiation of bioconjugated nanomaterials can offer a breakthrough solution to currently available therapies. The research will be focused on the optimization of such high selectivity towards cancers cells and the effect of the nanomaterials on the cells. The experimental work will focus on the characterization of bioconjugation of nanomaterials by confocal laser scanning microscopy (CLSM) combined with advanced atomic force microscopy (AFM) in a liquid environment. The work will encompass - detailed characterization of cells via AFM before and after the treatment with nanomaterials, research and design of the functionalization of AFM tips for tethering different biomolecules, AFM single-molecule force spectroscopy characterization of biomolecules towards cell membranes. The work will be realized at the Institute of Physics. For detailed information, please contact: adriana.annusova@savba.sk
    References:
    1. Lamprecht, C. et al., Biomedical Sensing with the Atomic Force Microscope, in Bhushan B. (eds) Nanotribology and Nanomechanics. 135–173 (Springer, 2017), 2. Kálosi, A. et al., A bioconjugated MoS2 based nanoplatform with increased binding efficiency to cancer cells, in Biomater. Sci. 8, 1973–1980 (2020)
    Contact: adriana.annusova@savba.sk
  14. Study program:
    Nuclear Chemistry and Radioecology / PriF UK
    Annotation:
    Contact: ondrej.sausa@savba.sk
  15. Study program:
    Physcial Engineering / FEI STU
    Annotation:
    The topic of this doctoral thesis is to investigate the dependencies of heat transport of natural materials and their composites, such as wood and chipboards. Composites based on wood mass connected by polymer matrix materials belong to the class of sustainable insulating materials with the potential for use in wooden buildings. Good thermal insulation properties predestinate them for use in hard climatic conditions. The effectiveness of their use in real climatic conditions depends on many parameters. Heat transport in such materials is multi-parametric because it is a simultaneous transfer of heat through the components of the structure. Experimentally, transient thermophysical methods will be used, namely the pulse transient method and the single-probe plane hot disk method. One of the tasks will be to determine the thermophysical parameters of wood boards for different directions of anisotropy of its structure. Another task is to develop a numerical model for simultaneous heat transfer through an inhomogeneous structure with different geometry of wood filler particles. The results obtained by the numerical model will be compared with the experimental data.
    Contact: vlastimil.bohac@savba.sk
  16. Study program:
    Physcial Engineering / FEI STU
    Annotation:
    Characterization of thermal properties of materials is a basic condition for their use in conjunction with their use in real conditions. Recently, we have noticed an increase in the number of non-stationary measurement methods based on the principle of dynamic temperature change. Transitient or dynamic methods use a non-stationary temperature field to characterize thermal transport and material parameters. Usually, the temperature response to the heat pulse generated by the heat source is monitored. Sensing the temperature response is realized in two ways. Either at a certain distance from the heat source or directly by the heat probe. Accordingly, we divide sensors into two-probe where the temperature is sensed by a thermocouple located outside the heat source and in the case of single-probe sensors, the temperature response is sensed by the heating element itself. The sensors are simultaneously senses the thermal response to a thermal disturbance in the form of an pulse or unit jump. From the thermal response, coefficients of thermal diffusivity and thermal conductivity and specific heat capacity are sought by applying the appropriate physical model by minimizing parameters. The development of single-probe sensors and methods for investigating the thermal properties of materials is therefore an interesting and necessary step towards the improvement of experimental measurement techniques. The results of the development of single-sensor methods and measuring electronics will enable more effective research and the solution of heat transport problems of new technologically interesting materials for thermal insulation or heat cooling applications.
    Contact: vlastimil.bohac@savba.sk

PhD themes

  • Study year 2023/24 / CSV