Thesis topics in Physics (for February 2024)

Application deadline: 26th November.

1. Towards hardware acceleration of Monte Carlo particle transport
   • Supervisor: dr hab. Przemysław Adrich, prof. NCBJ
   • Description: Monte Carlo particle transport simulation is a primary and indispensable tool of fundamental as well as applied science and nuclear engineering. Nowadays, particularly in high-energy physics, the demand for MC simulations is growing faster than the performance improvements of traditional computer processors, creating an ever-widening gap. A remedy is actively sought, and different approaches are being considered.
     Currently, Field Programmable Gate Arrays (FPGA) are emerging as an intriguing alternative to traditional CPUs. FPGAs are made of programmable logic and arithmetic blocks and memory elements that can be connected together using programmable interconnect. Essentially, an FPGA is a reconfigurable hardware capable of implementing an arbitrary algorithm. It has been demonstrated that for certain problem domains, e.g., in machine learning, finances, database processing, genomics, cryptography, FPGAs outperform CPUs by a significant margin. Monte Carlo particle transport appears to be well-suited for hardware acceleration using an FPGA. Up to now, limited research has been conducted in this area, aside from very preliminary studies with extremely simplified physics and geometry models.
     Here, we propose to undertake studies on the hardware acceleration of Monte Carlo particle transport. A primary objective is to assess the viability of FPGA acceleration for simulations involving realistically complex geometries and physics. To this end, coupled photon-electron transport, which has applications ranging from electromagnetic calorimeters to radiotherapy planning, appears both feasible and important.
     We are looking for candidates with basic knowledge of particle interaction with matter, fundamentals of Monte Carlo simulation and programming skills (C, C++).
   • Funding: NCBJ
2. Cosmology with gravitational lensing of the cosmic microwave background
   • Supervisor: dr hab. Paweł Bielewicz, prof. NCBJ
   • Description: Gravitational lensing of the cosmic microwave background (CMB) is a relativistic effect caused by the gravitational interaction of the CMB photons with matter inhomogeneities encountered during their travel from the last scattering surface to an observer. Reconstructed from correlated CMB ansiotropy gravitational potential of the lensing structures projected along the line-of-sight gives a unique image of the formation of the large scale structure at high redshifts and enables testing cosmological models at large scales. On the other hand, generated by the lensing effect divergence-free component of CMB polarisation has to be precisely estimated and corrected to be able to detect primordial gravitational waves produced during the inflationary epoch.
     This PhD project will involve research on different aspects of the CMB gravitational lensing effect including developing and implementation of algorithms for estimation of the gravitational lensing potential, cross-correlations with galaxy and radio surveys, correcting CMB maps for the lensing effect and constraining amplitude of the primordial gravitational waves and sum of neutrino masses. The PhD student will analyse publicly available data from the Planck satellite and other ongoing and near future CMB experiments. The cross-correlation studies will be realized within the framework of the Rubin Observatory Legacy Survey of Space and Time survey. We seek strongly motivated PhD candidates with interest in cosmology who can demonstrate ability in programming and have experience in numerical methods.
   • Funding: NCBJ
3. Study the Higgs boson properties in its decays to tauons
   • Supervisor: dr hab. Michał Bluj, prof. NCBJ
   • Description: The aim of this PhD project is to study the Higgs boson properties in its decays to tau leptons (tauons). The primary goal will be to exercise the structure of the coupling between the Higgs boson and tauons. The Standard Model (SM) of fundamental interactions predicts that the coupling is even under the combined charge-parity (CP) symmetry, while a new CP-odd component is predicted by many of SM extensions. Presence of such a CP-odd component will lead to violation of the CP symmetry in Higgs and tau lepton interactions, which can help to explain observed matter-antimatter asymmetry.
     This measurement will be performed by analysing the correlation between the spins of the tau leptons produced in the Higgs boson decays using data collected by the CMS detector at the Large Hadron Collider (LHC) at CERN in 2022-2025 (LHC Run-3).
     The selected candidate will join our CMS group at NCBJ. He/she is expected to base in Warsaw with opportunities to travel to CERN, Geneva.
     We are looking for candidates highly motivated to scientific research with good analytical skills and have excellent programming skills (C++, python) and who is being able to establish a friendly collaboration with the international scientific community at CERN.
     The successful candidate is also expected participate in activities related to the operation of the trigger system of the CMS detector, as part of their service work within the Warsaw CMS group.
   • Funding: NCBJ
4. Impact of radiation damage on mechanical and structural properties of martensitic ferritic steels.
   • Supervisor: dr hab. Łukasz Kurpaska, prof. NCBJ
   • Co-Supervisor: dr Peter Haehner
   • Description: Materials under neutron irradiation are subject to irradiation damage and degradation of their mechanical properties. However, neutron irradiation studies for research purposes are complicated, time-consuming, and expensive, so emulating neutron irradiation damage by much faster and cost-effective ion irradiation is of high interest. At the same time, ion irradiation avoids activation of the irradiated material. However, the emulation of neutron irradiation by ion irradiation damage is limited by transferability issues and experimental uncertainties linked to the limited penetration of the energetic ions.
     The goal of the work is to improve our understanding of the phenomena associated with the formation and evolution of ion irradiation-induced defects and their role in the deformation behavior in ferritic/martensitic (f/m) steels, incl. pure Fe, Fe9%Cr, Fe9%Cr-NiSiP and Eurofer 97. Nanoindentation will be carried out using different indenter shapes to study irradiation hardening. Radiation-induced defects will be identified by TEM. Complementary analyses will be carried out, including plasma-focused ion beam tomography of indents.
     The project aims at establishing and validating a comprehensive testing protocol with complementary investigations to support the experimental activities. An experimental/computational procedure is targeted for effectively characterizing ion irradiation as a surrogate for neutron irradiation. The project will also contribute to developing and validating models for size effects during nanoindentation in irradiated steels through a statistical sampling approach across a specimen surface. It is well known that size effects are influenced by irradiation; however, the origin has been debated. Micromechanical models and validation experiments will be performed that will account for geometrically necessary dislocations generated at the indent. Based on dislocation dynamics formulations in samples with various defects/defect clusters, a machine-learning approach will be developed to evaluate nanoindentation responses in irradiated metals.
     The Ph.D. project is expected to effectively improve experimental/computational protocols for the fast, safe, and reliable assessment of the irradiation impact on the mechanical properties of structural steels.
     The topic is in line with the research carried out by the NCBJ and in line with the mission of the JRC. Therefore, the Ph.D. candidate will conduct his/her research for up to 24 months at the Joint Research Centre in Petten under employment as a grant holder through the Collaborative Doctoral Partnerships (CDP) scheme (Agreement n. 36149). The candidate will be enrolled in NCBJ Ph.D. school and awarded a Ph.D. Degree in Physics at the end of the three to four-year Programme after successfully completing the entire Ph.D. requirements, including the successful defense of the Thesis as provided by the NCBJ Ph.D. school Regulations on Ph.D. Programmes.
   • Funding: NCN
5. Low surface brightness galaxies in the LSST era
   • Supervisor: dr hab. Katarzyna Małek, prof. NCBJ
   • Auxiliary Supervisor: dr Junais
   • Description: The upcoming Legacy Survey of Space and Time (LSST) will be the benchmark for the next decade, providing unprecedented depth and quality optical data on millions of galaxies, including low and high surface brightness galaxies, LSBs and HSBs, respectively. This PhD project focuses on the identification and analysis of LSBs, which are very diffuse and fainter than the typical night sky, using the LSST data. The PhD student will investigate intermediate galaxies between LSBs and HSBs to understand if there is an intrinsic separation or continuity between the two populations.
     In the framework of this project, the PhD candidate will perform morphological analysis on these galaxies to estimate their properties such as size, surface brightness, and concentration. Several widely used tools like Galfit, Photutils, Autoprof, and machine learning techniques will be used to compare and evaluate the robustness of different tools for optimal morphological estimation of faint galaxies. The student will also carry out a multi-wavelength analysis of these galaxies by compiling ancillary data from the literature (e.g., GALEX, Spitzer, JWST, Herschel). The CIGALE tool will be used to perform Spectral Energy Distribution (SED) fitting techniques to estimate the stellar mass, star-formation rate, and dust attenuation of the galaxies.
     Our team is an active member of the LSST collaboration with access to early data releases that will be available at the beginning of the 2024 year. We also have experts in the field of LSBs, galaxy morphology, as well as SED fitting. Therefore, this PhD project offers a unique opportunity for the student to gain expertise in all these aspects. The results of this research will provide essential insights into the nature of very faint galaxies and their role in galaxy formation and evolution scenarios.
   • Funding: NCBJ
6. ML-based methods to explore the low surface brightness Universe and search for rare astronomical objects
   • Supervisor: dr hab. Katarzyna Małek, prof. NCBJ
   • Co-Supervisor: prof. dr hab. Agnieszka Pollo
   • Description: Modern and near-future sky surveys open possibilities to explore the Universe further and deeper than ever before. The rising size of available data, however, poses a serious limitation: such data cannot be analyzed by old-fashioned methods anymore. With increasingly rising sizes of sky surveys, the application of automated techniques is no more a matter of choice but a necessity.
     Studies of low surface brightness Universe – galaxies and galaxy features so faint that their surface brightness is lower than that of the night sky – are now one of the most rapidly developing areas in astronomy. We are searching for a Ph.D. candidate who will develop and apply develop and apply, based on the present experience gathered in our group, machine learning methods for search and studies of low surface brightness galaxies and low surface brightness galaxy features. The topic can be extended to search for rare or even unexpected (anomalous) astrophysical objects with similar methods. The developed methodology will be applied to present-day and near-future big sky surveys, with the aim of preparing a methodology for the coming data from the Large Synoptic Survey Telescope. We are looking for candidates with a strong background in programming and machine learning applications.
   • Funding: NCBJ
7. Optimization of neutrino interaction selection in water Cherenkov detector
   • Supervisor: prof. dr hab. Ewa Rondio
   • Description: The water Cherenkov detectors played a very important role in discovering illusive nature of neutrinos. Now the biggest working detector is using this technique. For future plans one of the next generation detectors will continue along this way. In Poland several institutions participate in Polish Neutrino Group, which is strongly involved in these experiments:
     • presently data taking and analysis in T2K and Super-Kamiokande
     • for future – construction of Hyper-Kamiokande.
     The successful candidate for PhD studies will be involved in the detector construction for Hyper-Kamiokande, including installation in the undergroung cave in Kamioka as well as in the analysis of data from Super-Kamiokande including presently collected data with gadolinium added to the water. This opens new possibility for event classification and reconstruction. Experience gained in this classification will be used for preparation of methodology for new bigger detector and estimation of systematic uncertainty.
     Experience in programming will be very useful for the planned activity, as existing software is very advance making the work challenging.
     The project requires good communication skills and in many aspects is based on collaborative effort. Several visits to Japan will be required.
   • Funding: NCBJ
8. Testing new theories using precise calculations of Higgs particle properties
   • Supervisor: dr hab. Enrico Sessolo, prof. NCBJ
   • Auxiliary Supervisor: dr Wojciech Kotlarski
   • Description: The topic of the thesis is an analysis of New Physics models through the prism of Higgs bosons predicted by those models, using a state-of-the-art calculation of properties of said models Higgs sectors. To that end, a potential candidate is expected to take part in automatizing calculation of higher order corrections to Higgs bosons masses and decays in an arbitrary Beyond the Standard Model model. Depending on his/her interests, the work might include a mix of tasks like: work on renormalization and treatment of infrared singularities, numerical work/programing, phenomenological analysis of BSM models. A potential candidate will contribute to the creation of a computer program that could benefit the whole particle physics community.
   • Funding: NCN