Physics thesis topics (for October 2020)

  1. New generation of gravitational wave detectors and its potential for testing cosmology and fundamental physics.
    • Supervisor: prof. dr hab. Marek Biesiada
    • Description: First detections of gravitational waves (GWs) by LIGO/Virgo collaboration opened a new window on the Universe. Following this ground-breaking achievement, GW community proposed a third-generation underground detector called the Einstein Telescope, which will have an order of magnitude better sensitivity than current detectors. This means that it would be able to probe three orders of magnitude greater volume of the Universe leading to an unprecedented statistics of GW sources originating at high redshifts. Moreover, there are advanced actions toward launching space-borne detectors LISA and DECIGO probing GW spectrum at low frequencies inaccessible from the ground. Their reach will be even bigger than the ET. Such concerted multifrequency coverage will elevate GW physics from weekly or monthly detections to a high-statistics era allowing high-precision astronomy and confronting the General Theory of Relativity with a plethora of experimental tests. Based on the Monte Carlo simulations of realistic forecasts of future GW data, the sucessful applicant will study the following issues: i) cosmological tests based on standard sirens using only observables obtainable from GW signals alone (i.e. without knowing the redshift of the source, but knowing its luminosity distance), ii) observational signatures of gravitational lensing of GW signals at low frequencies, iii) joint multifrequency observations of inspiralling binaries from the space and from the ground and their potential to directly probe the expansion of the Universe and testing theories violating Lorentz invariance.
    • Funding: NCBJ Fellowship
  2. Integrated risk assessment for combined nuclear and chemical facilities
    • Supervisor: prof. dr hab. Mariusz Dąbrowski
    • Description: This project concerns the most demanding problems on risk assessment for the chemical installations coupled with High or Very High Temperature Reactors (HTR/VHTR) optimized to the process heat production. Replacement of the coal or gas boilers by HTRs within the chemical plants requires, among others, considering the interactions between nuclear and non-nuclear parts of the installation, combined together in one complex system. Independently developed risk models for chemical and nuclear parts of such facilities would not describe properly the real state of the whole system and thus need to be integrated. The aim of the PhD work is to develop the overall risk assessment framework for combined nuclear and chemical facilities by taking into account the events posing a challenge for safety of the nuclear installation after failure of one or more chemical systems and vice versa. Within this framework there is a need for identification of the critical elements, the failure of which could lead to severe accidents as well as the accident sequences. Significant improvement of the current status of knowledge is expected in characterization of the risk associated with the physical phenomena and chemical processes applied in one part of the system (chemical or nuclear) in the context of fragility of the other one. This includes also proposition of the risk metrics for such installation. The framework for an integrated risk assessment will also provide methods for assessing the risks associated with external hazards as the potential threats for one or both (nuclear and chemical) parts of the installation. The project might be developed in collaboration with Japan Atomic Energy Agency (JAEA) operating the High Temperature Test Reactor (HTTR).
    • Funding: PhD4Gen project
  3. Search for nuclear chirality in low excitation energy states of odd-odd isotopes
    • Supervisor: dr hab. Ernest Grodner
    • Description: Symmetries play a major role in the description of quantum many-body systems like heavy atomic nuclei which are composed of fermion particles.The quantum behaviour of such objects manifests itself through collective excited states decaying mostly via emission of gamma quanta.Experimental nuclear gamma spectroscopy is a tool to detect and trace these collective states and rare quantum phenomena taking place behind the scenes. In some cases these phenomena involve a process called the spontaneous symmetry breaking in atomic nuclei [1]. One of the most interesting and intensively studied symmetry of this kind is the chiral symmetry breaking in odd-odd nuclei [2, 3, 4] . The concept of chirality in the region of low nuclear excitation energies differs from chiral symmetry breaking in other fields of physics since it involves the time-reversal T operation instead of the space-inversion P. This makes nuclear chirality a unique phenomenon that, instead of parity, involves the time-reversal symmetry. The PhD project is focused on the experimental research of chiral-spontaneous symmetry breaking in atomic nuclei via lifetime measurements of their collective states. The obtained lifetime data describe the electromagnetic transition probabilities and electromagnetic matrix elements that are observables highly sensitive to occurrence of spontaneous chiral symmetry breaking in atomic nuclei. Lifetimes of such collective states are going to be measured using several techniques initially involving EAGLE HPGe multidetector setup in beam of heavy ion cyclotron both located at Heavy Ion Laboratory of the University of Warsaw. The obtained results will be used for subsequent experiment proposals and to continue nuclear chirality research abroad.
      [1] Stefan Frauendorf ”Spontaneous symmetry breaking in rotating nuclei”, Reviews of Modern Physics 73, 463 (2001)
      [2] E. Grodner at al., Physical Review Letters 97, 172501 (2006)
      [3] E. Grodner et al., Phys.Rev.Lett. 120, 022502 (2018)
      [4] Frauendorf, Meng Nuclear Physics A617, 131-147 (1997)
    • Funding: NCBJ Fellowship
  4. Nuclear Fuel Cycle studies of nuclear reactor fleet consisting of LWRs, HTGRs and other advanced reactors – development of the Nuclear Fuel Cycle Simulator – FANCSEE
    • Supervisor: prof dr hab. Wacław Gudowski
    • Description: In order to study material flow, material inventory, radioactivity and radiotoxicity of the final wastes in a nuclear power program it is obligatory to have a reliable and validated tool performing all necessary simulations. This PhD project is focused on development of an existing Nuclear Fuel Cycle Simulator FANCSEE which enables such simulations, but still requires a significant development. A candidate for such PhD project should have advanced skills in C++ programming and having good understanding of reactor physics and nuclear technology. Finally this simulator will be used for studying different scenarios of nuclear program development in Poland and other countries in order to optimize the costs of the back-end of the nuclear fuel cycle.
    • Funding: PhD4Gen project
  5. Search for super-stable super-heavy high-K isomers.
    • Supervisor: dr. hab. Michał Kowal
    • Description: Superheavy elements are extremely unstable systems with very low production cross-sections. Existing experimental facilities limit the possibilities for discovery of new nuclides to those synthesized with the cross-sections above 100 fb what is possible currently in selected laboratories, actually only in two of them, i.e. in DUBNA and in RIKEN. As the creation of new elements is a very difficult task as a parallel or additional line of study one could try a search for new, long-lived metastable states of already known heavy nuclei. Due to small structural overlap and strong centrifugal effect transition between non-analogical states is excluded. Different excitation energies of a high-K configuration in parent and daughter nucleus seem than particularly important for a hindrance of the alpha-decay. This, together with their relatively low excitation suggests a possibility that they could be isomers with extra stability – five and more orders of magnitude longer-lived than the ground states. This in turn would mean that chemical studies of such exotic high-K sates would be more likely than for quite unstable ground states. In this thesis, for the first time, we plan to include for two- and four-quasi particle states additional odd particle effect. With this, we are going to discuss the influence of the odd nucleons on the hindrance mechanism in the alpha decay process.
    • Funding: NCBJ Fellowship
  6. Deep and machine learning methods for searching for optical counterparts to gravitational wave events
    • Supervisor: prof. dr hab. Andrzej Królak
    • Auxiliary supervisor: dr Adam Zadrożny
    • Description: One of the hottest topics in today’s astronomy is searching and analyzing optical counterparts to gravitational wave events. Still there is only one such event observed, which is GW170817 / AT 2017gfo. It was observed during LIGO-Virgo Observing Run O2, which lasted 6 months and had one event that might plausibly produce optical counterpart. During O3 the third observing run there were more than 10 event that might have optical counterpart, but yet none was found. In order to make search more successful in upcoming LIGO-Virgo O4 science run (2022+) we would like to develop a strain of machine learning/deep learning methods for optical follow-up. The developed methods would be tested on TOROS collaboration telescopes during LIGO-Virgo O4 Observing Run. There is a possibility to expand scope of the project to electromagnetic data from POLAR-2 and LSST.
    • Funding: NCBJ Fellowship
  7. A roadmap for a CP violation signal in hyperon decays
    • Supervisor: dr hab. Andrzej Kupść
    • Description:  Violation of the charge parity (CP) symmetry is closely related to the baryon-antibaryon asymmetry puzzle and  may be harbinger of the physics beyond the standard model (SM). The Standard Model (SM) of particle physics predicts a tiny amount of CP violation exists but it is not sufficient to explain the overwhelming excess of the matter in the universe. The crucial property of baryons is their fractional spin, a quantum property which allows the ground state baryons to have two polarization states. Here, we plan to use a novel method to study CP symmetry for baryons containing strange quark, where the violation was never observed. The method uses baryon-antibaryon pairs produced in an electron-positron annihilations at the Beijing Electron Positron Collider (BEPCII). The spins of the baryons from such annihilations are correlated and polarized as recently observed for the first time.  Within the PhD project this novel method for the CP tests will be further developed to be used at BESIII and at the foreseen in the nearest future experimental facilities. The feasibility studies will use already collected BESIII data from J/psi resonance decays into baryon-antibaryon pair. The project includes participation in the BESIII experiment and a scholarship at Uppsala University.
    • Funding: NCN PRELUDIUM BIS
  8. Technical safety-related assessment of transmutation plant with liquid fuel (DFR)
    • Supervisor: prof. dr hab. Rafael Macian-Juan
    • Description: In the framework of this PhD work, safety-critical issues on the transient and accident behavior of transmutation plants are being examined in detail with the aid of the DFR system code(s) developed at TUM and NCBJ.  Based on event trees that take into account all significant component failures, transient analyzes, including startup and shutdown simulations and stability analyzes are performed, including consideration of the mechanical integrity of the component materials as a result of abnormal occurrence or accidents, i.e. possible (component) consequential damages of abnormal occurrence or accidents are to be estimated. The aim is to prove that the plant fulfills all safety requirements that are set within the scope of the licensing procedure. The work within the PhD project will be carried out in the following four steps.
      1. Compilation of the principles of safety design of the MSR/DFRs. Development of event trees, which are the basis for the transient analyzes to be carried out in the next work step.
      2. Performing transient analyzes based on the event trees in 1. These are simulations with the calculation codes provided by TUM/NCBJ.
      3. Critical analysis of the simulation results from 2. and estimation of possible consequential damages.
      4. Development of a clear presentation of the safety characteristics and comparison of the different reactor variants.
    • Funding: PhD4Gen project
  9. HELP to find Hot DOGs
    • Supervisor: dr hab. Katarzyna Małek
    • Description: The most luminous infrared galaxies in the universe are thought to be massive galaxies with intense star formation during a key stage in their evolution. They are also extremely dust-obscured which means that these objects are very bright in the IR but typically faint at UV/optical wavelengths. There are several populations of galaxies that are known to be in such stages, and one of them is the population of Hot Dust-Obscured Galaxies (Hot DOGs). Hot DOGs are characterized by very red mid-IR colours and by hot dust temperatures (T>60 K). In this topic of the PhD thesis, we plan to apply machine learning techniques to classify and select possible Hot DOGs in the Herschel Extragalactic Legacy Survey (HELP) covering ~1300 deg2 area on the Sky. In the next step, a careful analysis of the IR images can help to clean the sample to prepare it for the final study of those extreme sources at different redshift ranges.
    • Funding: NCBJ Fellowship
  10. Novel Research with Short-lived Atomic Nuclei
    • Supervisor: prof. dr hab. Zygmunt Patyk
    • Auxiliary supervisor: dr Volha Charviakova
    • Description: A successful candidate could perform unique research with short-lived nuclei to contribute to a better understanding of the strong and weak interaction and the origin of the chemical elements in the Universe. The discovery of new isotopes and the measurements of their properties will be a central effort. The experiments will be mainly performed at FAIR-GSI in Darmstadt, Germany, where Poland is a member state since the foundation.
    • Funding: NCBJ Fellowship
  11. QCD in the Electron-Ion Collider Era
    • Supervisor: Prof. dr hab. Lech Szymanowski
    • Description: Our understanding of protons and neutrons, or nucleons—the building blocks of atomic nuclei—has advanced dramatically, both theoretically and experimentally, in the past half century. It is known that nucleons are made of fractionally charged “valence” quarks, as well as dynamically produced quark-antiquark pairs, all bound together by gluons, the carrier of the strong force. A central goal of modern nuclear physics is to understand the structure of the proton and neutron directly from the dynamics of their quarks and gluons governed by the theory of their interactions, quantum chromodynamics (QCD). The designed Electron Ion Collider (EIC)  is the instrument that can answer many of these fundamental questions. The topics of this PhD project focus on either theoretical or phenomenological investigation of some processes which will play a key role on EIC physics studies and on the interpretation of the results of the ongoing experiments at LHC, JLAB, RHIC and COMPASS. Successful candidate will have the opportunity to collaborate with world-known physicists from France, Spain and USA.
    • Funding: NCBJ Fellowship
  12. Study of Vector Boson Scattering in the same-sign WW process at the CMS experiment
    • Supervisor: dr hab. Michał Szleper
    • Description: Vector Boson Scattering (VBS) processes belong to the most important tests of the Standard Model of particle physics.  They probe Higgs couplings to vector bosons W and Z, as well as triple and quartic couplings between bosons themselves.  In addition, scattering of longitudinally polarized vector bosons provides a direct glimpse of the mechanism of electroweak symmetry breaking.  In recent years the CMS and ATLAS experiments at CERN have observed for the first time the VBS processes at a level roughly consistent with Standard Model expectations, but more data is crucial in order to place better limits on Beyond Standard Model physics.  The successful applicant will participate in the analysis of the same-sign WW scattering channel in the leptonic W decay mode from CMS data collected during LHC Run 3.  He/she is expected to fully implement and develop the “clipping” technique to derive limits interpretable in the language of Effective Field Theories and to develop techniques to tag W/Z polarizations.  The project will also involve technical work on the CMS muon trigger system as part of the Warsaw CMS group activities.
    • Funding: NCBJ Fellowship