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 2024/25

  1. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    Tensor Network represents a modern mathematical tool that can accurately describe quantum states. We focus on the description of strongly correlated spin (magnetic) systems. A quantum tensor-product state represents the tensor network. It carries physical degrees of freedom which are interconnected via auxiliary (non-physical) degrees of freedom controlling correlations and quantum entanglement. During the PhD studies, we will analyze non-trivial topological phases by the quantum entanglement entropy, concurrence, negativity, and standard observables. Since these spin systems are not exactly solvable, we will develop novel numerical procedures using any preferable programming language (e.g., Python, Julia, C++, etc.) The goal is to propose alternative methods of tensor networks originating in renormalization-group techniques. We also intend to analyze hyperbolic curved lattices to revisit quantum gravity from a different viewpoint.
    Contact: andrej.gendiar@savba.sk
  2. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    Critical reconsideration on assumptions on the interpretation of recorded data and certification of quantum features. The precise problem formulation depends on the preferences of PhD student. The subject includes area of device-independent protocols, quantum memory channels, quantum network theory, direct estimation protocols and higher-order quantum structures.
    Contact: mario.ziman@savba.sk
  3. Study program:
    Theoretical and Mathematical Physics / FMFI UK
    Annotation:
    Current stage of development of quantum computers is termed as Noisy intermediate-scale quantum (NISQ) era. Capabilities of such devices are quite limited with respect to quality and quantity of the qubits, performed gates or types of measurements. Thus, to fully unlock their potential implemented tasks should be carefully optimized with respect to usage of those resources. The goal of the student will be to learn and further develop methods for optimization of higher order maps with chosen resource and causal structure. The student should also work with and improve methods for finding quantum circuit implementations of such optimal maps and other known or newly developed quantum information processing tasks. The research goals are planned to be addressed mostly by analytical means, but also computer assisted approach can be envisioned and would be welcomed.
    Contact: michal.sedlak@savba.sk
  4. Study program:
    Physics of Condensed Matter and Acoustics / FMFI UK
    Annotation:
    A PhD in the theory of quantum computing with solid-state devices with emphasis on simulations and numerics [1]. The goal is to develop models applicable to current quantum dot spin-qubit devices [2]. After the initial orientation, we will choose one of the platforms based on electrons in silicon, such as Si/SiGe heterostructures and Si-MOS finFETs, or holes in germanium, such as Ge/SiGe heterostructures or Ge/Si core-shell nanowires. The candidate will get acquainted with ab initio methods (DFT and tight-binding), microscopic simulation methods (COMSOL or similar), and the k-dot-p theory [3]. Combining these methods, we aim to obtain models that are capable of explaining the experimental data and enable one to suggest improvements in device design and operation. The candidate will have the opportunity to collaborate with the leaders in spin-qubit theory (D. Loss, Basel, CH) and experiments (S. Tarucha, RIKEN, JP).
    References:
    [1] W. H. Press, et al., Numerical Recipes, 3rd edition (2007). [2] G. Burkard, et al., Semiconductor spin qubits. Rev. Mod. Phys. 95, 025003 (2023). [3] Dresselhaus, et al., Group theory: application to the physics of condensed matter, Springer-Verlag Berlin (2008).
    Contact: denis.kochan@savba.sk
  5. Study program:
    Nuclear and Subnuclear Physics / FMFI UK
    Annotation:
    The local free volume in polymers investigated by positronium annihilation makes it possible to characterize many properties of polymer networks such as, for example, the thermal expansivity of the free volume, the fraction of the free volume, significant temperatures of structural transitions, etc. It is an effort to prepare new materials with suitable properties, according to the required applications. We can influence the properties of polymers not only in the polymerization process, but also by further processing already hardened structures. Thus, for example, by applying high pressures on hardened samples, their material properties can be additionally changed. The aim of the study is to monitor the extent of reversible and irreversible processes in the polymer network after the application of high pressure (0-100 MPa) by measuring the lifetimes of positronium under defined external conditions. Local free volumes will be determined from lifetimes using appropriate models and will be correlated with the results of other standard characterization techniques such as infrared spectroscopy, dielectric spectroscopy, differential scanning calorimetry. A benefit in the knowledge of new materials is expected. The project is part of international cooperation.
    Contact: ondrej.sausa@savba.sk
  6. Study program:
    Nuclear and Subnuclear Physics / FMFI UK
    Annotation:
    Detailed investigation of the phase behavior of water in the presence of cryoprotectants such as DMSO, glycerol, ethylene glycol and selected carbohydrates, using local free volume changes determined from Ps lifetimes over a wide temperature interval. The combination of microscopic and macroscopic approaches (positron annihilation time spectroscopy-PALS and differential scanning calorimetry, DSC) will contribute to creating a more complex picture of the processes taking place in model mixtures at the microstructural level. Significant practical imact of research on the field of medicine and biology.
    Contact: ondrej.sausa@savba.sk
  7. Study program:
    Nuclear and Subnuclear Physics / FMFI UK
    Annotation:
    Nuclei with just one particle (proton, neutron) outside the closed shells are of a particular interest. Investigation of the neutron-deficient bismuth isotopes (Z = 83) play an important role in the understanding of shell evolution, nuclear deformation and shape coexistence phenomena in the vicinity of lead. Bi nuclei of this study are 17 and 18 neutrons, respectively, away from the doubly magic Pb-208 nucleus, relatively close to neutron mid-shell. Both the Bi-191,192 isotopes are located in the region with strong manifestation of shape coexistence and high-spin isomeric states associated with multi-quasiparticle configurations [1, 2, 3]. The Bi-191 isotope, particularly, is located right on the edge in the bismuth isotope chain, where prolate and oblate nuclear structures compete [4, 5]. The data were collected in the experiment at the Accelerator laboratory of the University of Jyväskylä (JYFL), Finland. In the data analysis, the (in-beam) gamma and decay spectroscopy tools will be used.
    References:
    1. A. Herzáň et al., Phys. Rev. C 92, 044310 (2015). 2. A. Herzáň et al., Phys. Rev. C 96, 014301 (2017). 3. A. Herzáň,et al., Eur. Phys. J. A 56, 165 (2020). 4. P. Nieminen et al., Phys. Rev. C 69, 064326 (2004). 5. M. Nyman et al., Eur. Phys. J. A 51, 31 (2015).
    Contact: andrej.herzan@savba.sk
  8. Study program:
    Nuclear and Subnuclear Physics / FMFI UK
    Annotation:
    The presented topic is part of a very successful experimental program focused on the study of neutron-deficient odd-mass gold isotopes. These nuclei have so far been investigated by various spectroscopic methods (e.g. in-beam, decay, and LASER spectroscopy). Research of this type allows us to study phenomena such as shape coexistence, evolution of deformation, etc. For a deeper understanding and the possibility to compare experimental data with theoretical models, it is necessary to know the reduced transition probabilities of electromagnetic transitions in nuclei that are input for the nuclear matrix elements. The reduced matrix elements contain information about the nuclear structure. This is not possible without accurate measurement of the lifetimes of excited states in nuclei. The topic is also part of the research grants, which guarantees the financial support. During the PhD studies, candidate will take part in the experiments performed in the laboratories: JYFL, Finland; CERN-ISOLDE and will present the results at international conferences. Knowledge of the English language at least at a moderate level is necessary. Knowledge of some of the programming languages and packages is an advantage: JAVA, C++, ROOT, GEANT, RadWare.
    References:
    1. D. J. Rowe, J. L. Wood, Fundamentals of nuclear models: foundational models, WSPC (2010), ISBN-13: 978-9812569554. 2. D. Jenkins, J. L. Wood, Nuclear Data: A primer, IoP Publishing (2021), ISBN-13:‎ 978-0750326728. 3. J. Suhonen, From nucleons to nucleus, Springer (2007), ISBN-13: 978-3-540-48859-0.
    Contact: andrej.herzan@savba.sk
  9. Study program:
    Nuclear and Subnuclear Physics / FMFI UK
    Annotation:
    The proposed project of PhD. thesis deals with performance and analyses of the data acquired at the University of Jyvaskyla in Finland. Recently we performed study of high-spin isomeric state in the 179Au isotope, which decays through defomed intruder configurations. The experiment used non-standard configuration of detectors at the focal plane of the RITU separator. This allowed to increase collected statistics by an order of magnitude. The student will analyse the data, perform theoretical calculations based on the particle-plus-triaxial-rotor model and interpret the results. Another experiment, aiming on 181Au has been recently approved by the PAC. In this experiment, we will search for analogous isomeric state, which is expected to exist. The data will be also analysed by the candidate. PhD. student will learn fundaments of the analyses of gamma-ray spectroscopy data for exotic isotopes, principles of maintenance of gamma-ray detectors, design of time-of-flight systems, corresponding electronics, cryogenic and vacuum techniques. The group at the Insitute of Physics, Slovak Academy of Sciences is composed of internationally recognized experts and actively collaborates with CERN, INFN Legnaro, University of Liverpool and University of Jyvaskyla. Therefore, the candidate must have strong ability to work in the international research team.
    References:
    1. M. Balogh et al., Phys. Rev. C 106, 064324 (2022). https://doi.org/10.1103/PhysRevC.106.064324 2. M. Venhart et al., Phys. Lett. B 695, 82 (2011). https://doi.org/10.1016/j.physletb.2010.10.055 3. K. Heyde and J. L. Wood, Rev. Mod. Phys. 83, 1655 (2011). https://doi.org/10.1103/RevModPhys.83.1467
    Contact: martin.venhart@savba.sk
  10. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    The goal of this thesis work will be to leverage quantum resources that came available to experimentalists since the second quantum revolution to either investigate and better understand fundamental concepts of the quantum theory or demonstrate potentially new applications for future quantum technologies. This work will be achieved through the realization of several photonic-based experimental setups: single photon sources, generation of entanglement, spectroscopy-based stabilization schemes for feedback loop and more.
    Contact: djeylan.aktas@savba.sk
  11. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    Photothermal therapy triggered by irradiation of bioconjugated nanomaterials can offer a breakthrough solution in the currently available cancer therapies. Up until now nanomedicine-oriented works lacked detailed nanoscale investigations of conjugates’ binding dynamics, self-assembled structures, composition and organization of proteins, nanoparticle-protein complexes, and the nanoimaging of phototherapy induced changes in molecular bonds and nano-bio assemblies. This work encompasses the study of the properties and activity of MoOx and MXene-based nano-bio conjugates on a fundamental nano-level, in order to understand particular phenomena, including their interaction with cells. The candidate will master nanoparticle and conjugate design and their in-depth characterization (physical, chemical, biological). Advanced microscopy techniques will be used, such as Confocal Raman Microscopy, AFM Force Spectroscopy, correlative CRM-AFM and near field scanning optical imaging. This proposed topic allows the candidate to extend his/her knowledge through original research and critical analysis.
    References:
    Annušová et al, ACS Omega, 2023, 8, 47, 44497–44513, doi: 10.1021/acsomega.3c01934; Nan et al, Appl Spectrosc Rev, 2021, 56, 7, 531–552, 2021, doi: 10.1080/05704928.2020.1830789; Lamprecht, C. et al., Biomedical Sensing with the Atomic Force Microscope, in Bhushan B. (eds) Nanotribology and Nanomechanics. 135–173 (Springer, 2017)
    Contact: adriana.annusova@savba.sk
  12. 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
  13. Study program:
    Quantum Electronics, Optics and Optical Spectroscopy / FMFI UK
    Annotation:
    Solid-state batteries (SSBs) will play a key role in solving the future of electromobility due to their improved safety and potentially higher energy density. However, a deeper understanding of the redox reactions in SSBs on very short time scales is essential for their further development. In this project, we aim to develop an ultrathin SSB with an optical switch that allows to trigger the discharge of the battery and thus track the redox reaction with a temporal resolution down to femtoseconds. We will employ ultrafast optical spectroscopy supported by experiments at the free-electron laser (FEL) in Hamburg. The experiments will be performed in collaboration with a HORIZON EU project - Ultrabat. For detailed information, email: peter.siffalovic@savba.sk.
    References:
    1. 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
  14. 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
  15. 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 2024/25 / CSV
  • Study year 2023/24 / CSV