PHYS SEMINAR:Neutron stars as windows into dense QCD at strong coupling

Guest: Tuna Demircik, Utrecht University

Title: Neutron stars as windows into dense QCD at strong coupling (PHYS)

Date/Time: 20 May 2025, 11:40

Location: FENS L067

Abstract: Solving Quantum Chromodynamics (QCD) at intermediate densities and temperatures remains a long-standing open problem. Traditional methods fail in this regime, leaving the precise phase structure of QCD still unknown. Addressing this fundamental challenge is essential for understanding matter under extreme conditions, such as those found inside neutron star cores, in the early universe moments after the Big Bang, and the matter created in heavy-ion collision experiments. This talk broadly covers my research, introducing a recently developed novel framework for describing the equation of state of hot and dense QCD. The framework bridges the gap in theoretical predictions at intermediate densities by using the gauge/gravity duality, which maps the strongly coupled QCD to classical higher dimensional gravity. The model combines predictions from the gauge/gravity duality with input from lattice field theory, QCD perturbation theory and traditional nuclear theory methods. I will demonstrate how this framework has enabled significant advances in modeling neutron star interiors, interpreting and predicting gravitational wave signals from neutron star mergers, and probing exotic quark matter phases such as color-superconductor and spatially modulated phases. Additionally, I will briefly discuss how gauge/gravity duality enhances our understanding of relativistic (magneto-)hydrodynamics, which is crucial for heavy-ion collision experiments. The talk concludes by highlighting my future research directions and outlines how these align with and enrich the research/teaching environment at Sabancı University.

Bio: Tuna Demircik is currently a postdoctoral researcher at the Institute for Theoretical Physics, Utrecht University, the Netherlands. After completing his bachelor's degree at Izmir Institute of Technology, he earned his Ph.D. in Physics from Sabancı University in 2017, specializing in applications of gauge/gravity duality to Quantum Chromodynamics (QCD). He subsequently held postdoctoral positions at Ben-Gurion University of the Negev (Israel, 2017–2020), the Asia Pacific Center for Theoretical Physics (South Korea, 2020–2022), and Wroclaw University of Science and Technology (Poland, 2022–2024). These international appointments provided him broad exposure to diverse scientific approaches and fostered collaborations across theoretical high-energy physics, astrophysics, nuclear physics, numerical relativity, and experimental heavy-ion physics. His research is notable for its interdisciplinary scope, integrating theoretical frameworks from various domains and connecting them to observational and experimental phenomena. He has developed pioneering hybrid gauge/gravity models of hot and dense nuclear/quark matter, enhancing key insights into neutron star interiors, gravitational-wave signals from mergers, and the quark-gluon plasma produced in heavy-ion collisions.