Converging results from different approaches locate the critical end point (CEP) of QCD at large chemical potential, i.e. in the realm of dense QCD. We summarise recent theoretical results within functional methods on the location of the CEP and its variation under systematic changes of the light and strange quark masses. We furthermore discuss the physics at large chemical potential including...
The QCD cross-over line in the temperature (T) - baryo-chemical
potential ($\mu_{B}$) plane has been computed by several lattice
groups by calculating the chiral order parameter and its susceptibility
at finite values of $\mu_{B}$ . In this work we extract from the
peak position of the static quark entropy ($S_{Q}(T,\mu_{B})$) in
T, which is based on the renormalized Polyakov loop. This...
First, the importance of the chiral anomaly in the QCD vacuum is briefly reviewed. Besides pseudoscalar mesons, it may affect other resonances. To this end, a mathematical object called `polydeterminant' is introduced. Next, the role of the chiral anomaly at nonzero temperature is investigated. In particular, the Columbia plot (the order of the phase transition in dependence of the quark...
We explore the validity of finite-size scaling of net-proton number cumulants as a tool to search for evidence of a critical point in the QCD phase diagram. We show that in central Au+Au collisions at $\sqrt{s_{\rm{NN}}} = 7.7$ GeV and above, the second cumulant C2 as a function of rapidity bin width follows a power-law consistent with scale invariance. We then show that for any bin width, C2...
We propose an observable to probe the content of a bath of quarks and gluons at finite temperature and chemical potential, the net quark number gain $\Delta Q$. QCD is controlled by different degrees of freedom in the various sections of its phase diagram, notably hadrons at low temperatures (and chemical potentials) and quarks and gluons at high temperatures. However, studying the relevant...
We investigate the thermodynamics of heavy-quark QCD in the hopping-parameter expansion (HPE) in an analytic manner. We develop a procedure to calculate the grand potential of heavy-quark QCD in the HPE using a technique based on the cumulant expansion. Applying this method to the analysis of thermodynamics, we derive the formula for the grand potential expressed in terms of the cumulants of...
The high-precision heavy quarkonium data from LHC Run 2 and the ongoing Run 3 provide a unique window into the properties of hot nuclear matter and the Quark-Gluon Plasma (QGP). To make full use of this data, it is crucial to go beyond traditional observables such as the nuclear modification factor $R_{AA}$ and elliptic flow $v_2$, and instead develop new probes that are more directly...
We calculate the leading and subleading corrections to the real-time static potential in a high-temperature quark-gluon plasma for distances smaller than the screening length. The calculation involves one-loop 2- and 4- point functions in the hard-thermal-loop effective theory. We use our results to estimate the binding energy, the decay width, and the dissociation temperature of the...
Cold and dense QCD matter may break rotational invariance spontaneously. One candidate phase is the chiral density wave, which exhibits an anisotropic chiral condensate, and which is conjectured to occur in the vicinity of the quark-hadron transition. I will employ a nucleon-meson model that allows for a chiral phase transition to explore the possibility of a chiral density wave in nuclear...
Including the effects of the chiral anomaly in Chiral Perturbation Theory at finite baryon chemical potential, it has been shown that neutral pions form an inhomogeneous phase dubbed the "Chiral Soliton Lattice" (CSL) above a certain critical magnetic field. Above a second, even higher critical field, the CSL becomes unstable to fluctuations of charged pions, implying they condense.
I will...
An understanding of the properties of the quark-gluon plasma (QGP) is important for the interpretation of experimental data on the bulk observables, as well as on jet and heavy-quark attenuation in heavy-ion collisions. However, gaining this knowledge is a challenging task, since it pertains to the non-perturbative regime of QCD, for which only limited information from lattice QCD is currently...
We will discuss the recent developments in renormalization group improvements of the cold and dense QCD pressure (Phys. Rev. D 111, 034020 and Phys. Rev. Lett. 129, 212001) at next-to-next-to leading order (NNLO) through the renormalization group optimized perturbation theory (RGOPT) and at all-order resummation of the soft modes. RGOPT applied for the very first time at NNLO displayed a...
In this talk I will discuss QCD at finite isospin density at zero temperature and zero baryon density. This is system is of particular interest since there is no sign problem and one can perform lattice simulations. I will present results for the speed of sound from NLO chiral perturbation theory (chipt) and the quark-meson model in the Bose-condensed phase. The latter is able is in good...
We discuss the phase structure of SU(2) Yang-Mills thermodynamics. For the deconfining phase, where the thermal ground state is composed of densely packed Harrington-Shepard calorons and anticalorons, subject to transient holonomy shifts, we compute the topological susceptibility as an effective contact term based on the Veneziano-Witten formula. (The contribution of effective thermal...
We explore the interplay between Berry curvature and topological properties in single-flavor color superconductors, where quarks form spin-one Cooper pairs. By deriving a new relation, we connect the topological nodal structure of the gap function in momentum space to the (non-Abelian) Berry flux associated with paired quarks. This generalizes the early work by Li and Haldane [1] to systems...
We discuss the dynamics of the topologically nontrivial sectors with non-trivial holonomy in strongly coupled QCD in the background of the expanding universe characterized by the Hubble scale $H\ll \Lambda_{QCD}$. We argue that the vacuum energy and the de Sitter phase emerge dynamically with the scale $\rho_{DE}\approx H\Lambda_{QCD}^3 \approx (10^{-3} eV)^4$, which is amazingly...
The QCD axion, originally proposed nearly five decades ago as a solution to the strong CP problem, remains one of the most compelling dark matter candidates. In this talk, I will explore the possibility that axions may undergo Bose-Einstein condensation in the dense cores of neutron stars, where extreme baryon densities could facilitate such a phase. Employing Chiral Perturbation Theory in...
In the coalescence of neutron stars the bulk viscous dissipation offers a potential opportunity to infer properties of neutron star matter by estimating its effect on the gravitational wave emission. To this end, we compute the bulk viscosity in unpaired quark matter considering the electroweak processes allowed in the neutrino-transparent regime at low temperatures. Using the equations of...
Isospin-equilibrating weak processes, called ``Urca" processes, are of fundamental importance in astrophysical environments like proto-neutron stars, neutron star mergers, and supernovae. In these environments, matter can reach high temperatures of tens of MeVs and be subject to large magnetic fields. We thus investigate Urca processes at different temperatures and field strengths by...
We study rotating hybrid stars, with a particular emphasis on the effect of a deconfinement phase transition on their properties at high spin. Our analysis is based on a hybrid equation of state with a phase transition from hypernuclear matter to color-superconducting quark matter, where both phases are described within a relativistic density functional approach. By varying the vector meson...
We present a comprehensive investigation of color-superconducting phases in compact stars using the renormalization group-consistent Nambu–Jona-Lasinio (RG-NJL) model [1]. By systematically varying vector and diquark coupling constants, we analyze their effects on the equation of state, speed of sound, and resulting mass-radius relations. Our models demonstrate that stable color-flavor-locked...
An intriguing hypothesis states that ordinary hadronic matter in bulk is a metastable state (i.e., a local minimum) of strongly interacting matter, while strange quark matter (SQM) is absolutely stable (i.e., the global minimum) in bulk. A potential barrier that prevents a spontaneous deconfinement transition of ordinary hadronic matter into SQM would separate these two phases.
Our work aims...
We investigate color superconductivity in two-flavor QCD and its impact on the equation of state for dense matter in neutron stars. Employing a quark-meson-diquark model truncation within the functional renormalization group framework, we analyze the formation of diquark and chiral condensates and characterize the resulting superconducting phase at high baryon densities.
Our results provide...
Different parts of neutron stars (NSs) probe all fundemantal interactions of particle physics: the strong nuclear force is behind the bulk thermodynamic properties of their constituent matter, electroweak interactions are needed to describe equilibration and transport phenomena during binary NS mergers, and information on QED scattering processes at ultrastrong magnetic fields is required to...
TBA
An important question in heavy-ion collisions is how the initial far-from-equilibrium medium evolves and thermalizes while it undergoes a rapid longitudinal expansion. In this presentation, I will show how to use the two-particle irreducible (2PI) effective action to address this question, focusing on phi^4 scalar theory truncated at three loops. I will present numerical results for quantities...
At the earliest stage of ultrarelativistic heavy-ion collisions the produced matter is a highly populated system of gluons called glasma which can be approximately described in terms of classical chromodynamic fields. Although the system's dynamics is governed by Yang-Mills equations, glasma evolution is shown to strongly resemble hydrodynamic behavior. We discuss glasma collective flow and we...
In this talk, we present a study of the out-of-equilibrium CME conductivity via Kubo formulas using lattice QCD simulations. We present an analytic study of the CME Kubo formula in 1-loop perturbation theory, which sheds light on the nature of the CME in a system of non-interacting fermions. We then determine the Euclidean correlator as a function of the (imaginary) time using full dynamical...
In the regime of three light quark flavors, conventional expectations predict a first-order chiral phase transition. However, recent lattice QCD results suggest the transition could instead be second order in the chiral limit. We investigate this scenario using an extended linear sigma model in the meanfield approximation, with particular emphasis on the role of anomalous $U(1)_A$-breaking...
Dileptons are considered to be an important observable, in the context of studying the characteristics of the deconfined phase of quark gluon plasma (QGP). Historically, the dilepton production rates (DPR) from the QGP have been studied using two different approaches. In the quantum field theory (QFT) approach, the DPR is expressed in terms of the thermal expectation value of the...
We study the bulk viscosity of moderately hot and dense, neutrino-transparent colour superconducting quark matter arising from weak-interaction-driven direct URCA processes. The quark matter is modeled using the Nambu-Jona-Lasinio model extended to include both vector interactions and the 't Hooft determinant term. The superconducting phase is described by using the two-flavour red-green...
We review recent progress towards the understanding of the QCD phase diagram using tools based on effective theories, Ward Identities (WI) and resonances at finite temperature and chemical potentials.
Various relevant observables such as scalar and topological susceptibilities can be obtained within this framework and are consistent with recent lattice analyses. In particular, we show...
In this talk I will discuss the three-flavor quark-meson model including color superconductivity, with emphasis on the 2SC and CFL phases. We extend the quark-meson model to the quark meson diquark model. This is a renormalizable low energy effective model that describes the superconductive phases of QCD. We calculate the thermodynamic potential including quark loops. We map out the phase...
We explore the role of color superconductivity in quarkyonic matter under the conditions of electric and charge neutrality at β-equilibrium, as relevant for neutron stars. By explicitly incorporating color-superconducting pairing gap into the phenomenological model of a crossover transition from hadron to quark matter, we extend the known quarkyonic framework suggested by McLerran and Reddy to...
We present the in-medium mass modification of $D$ ($D^+$, $D^0$) and $\bar D$ ($D^-$, $\bar {D^0}$) mesons when immersed in isospin asymmetric $\Delta$ resonance matter by using the chiral SU(3) hadronic model extended to the SU(4) sector.
The interactions of $D$ and $\bar D$ mesons with decuplet baryons ($\Delta^{++,+,0,-}$) are explicitly taken into account in the dispersion relations in...
In this talk I will present a new method to study the QCD phase diagram at finite baryon chemical potential, using hadronic correlators. Specifically, the approach exploits the degeneracy between the vector and axial vector channels upon chiral symmetry restoration. The temperature at which this degeneracy occurs shifts as $\mu_B$ is increased, allowing us to follow the change of $T_{c}$ along...
Dense QCD matter can feature a moat regime, where the static energy of mesons is minimal at nonzero momentum. We elucidate various features of this regime in this work. To capture the main effects, we use a two-flavor quark-meson model and put forward an efficient renormalization scheme to account for the nontrivial momentum dependence of meson self-energies in the moat regime.
We show that...
Electromagnetic field produced in non-central heavy ion collisions
play a crucial role in phenomena such as chiral anomalous effects,
directed flow of mesons and splitting of spin polarization of $\Lambda/\bar{\Lambda}$.
A precise description of these fields is essential for quantitatively
studying these effects. We investigate the space-time evolution of the electromagnetic fields by...
We present an improved ansatz for the self-energy of confined quarks within a density functional formalism in order to investigate the thermodynamics of dense matter, particularly, the speed of sound and baryon fluctuations, including studying their approach toward the conformal limit. The formulation offers insight into how characteristic scales inherent to a theory lead to mimicking...
Fragmentation functions are fundamental components of the factorization approach which is used to calculate the production cross sections of heavy-flavor hadrons within QCD. Due to their non-perturbative nature, they cannot be computed a priori and are typically extracted from measurements in clean environments such as electron-positron (e$^+$e$^-$) or electron-proton (e$^-$p) collisions....
The experimental observation of the spin polarisation of the outgoing hadrons in non-central heavy ion collisions implies the existence of a strongly vortical QGP medium with finite spin density. We consider the effect of finite spin density on the QCD phase diagram using the Linear Sigma model coupled to quarks (LSMq). In our approach, we introduce the finite spin density via a quark spin...
We present a study of the structure of the chromoelectrical field created by a static quark-antiquark pair in lattice QCD with 2+1 flavours of dynamical quarks, where the quark masses are set to their physical values. The analysis covers a wide range of temperatures both above and below the chiral crossover, and explores varying quark-antiquark distances, with the aim of identifying signals of...
We study the magnetic properties of the Hadron Resonance Gas (HRG) (which is created in ultra-relativistic heavy-ion collisions or studied on the lattice) in the presence of a constant magnetic field. Instead of the simplified approach$^{1,2}$ of taking the gyromagnetic ratio of a hadron as $g=2|Q|$, we consider the physical value of $g$ as measured in experiments or estimated theoretically....
We investigate the rotational Brownian motion of heavy quarks in a QCD medium and present predictions for the polarization of open heavy-flavor hadrons. Specifically, we derive expressions for vector and tensor polarization, which correspond to baryon spin polarization and meson spin alignment, respectively. Furthermore, we suggest that the transverse momentum dependence of heavy quark...
We compute the pressure, chiral condensate and strange quark number susceptibility from first principles within perturbative QCD at finite temperature and very high magnetic fields up to two-loop and physical quark masses. We also discuss cold and dense quark matter in the presence of a very strong magnetic field using perturbative QCD at finite density. The effectively negligible contribution...
A recently formulated extension of perfect spin hydrodynamics, which includes second-order corrections in the spin polarization tensor to the energy-momentum tensor and baryon current, is studied in the case of a one-dimensional boost-invariant expansion. The presence of second-order corrections introduces feedback from spin dynamics on the hydrodynamic background, constraining possible spin...
The extraordinary densities achieved in the cores of neutron stars make them ideal astrophysical laboratories for investigating hypernuclear matter. Recent multi-messenger observations impose stringent constraints on the neutron star equation of state, allowing for tests of models that incorporate exotic components such as hyperons. For example, precise measurements of neutron star masses—such...
We study neutron stars (NSs) admixed with self-interacting bosonic dark matter (DM), motivated by recent observational data from NICER and LIGO/Virgo. In this framework, sub-GeV bosonic DM can accumulate as a dense core or form an extended halo around the NS, significantly affecting its mass, radius, and tidal deformability. By varying the DM particle mass, self-coupling strength, and its...
The encoded nuclear structures related to flow fluctuations can be investigated at a fixed impact parameter in ultra-relativistic ion collisions through the concept of factorization breaking. This phenomenon is explored by analyzing momentum-dependent correlations among flow harmonics across distinct kinematic bins, specifically in terms of pseudorapidity ($\eta$)[1] or transverse momentum...
We employ lattice simulations to search for the critical point of quantum chromodynamics (QCD). We search for the onset of a first order QCD transition on the phase diagram by following contours of constant observables (e.g. entropy density) from imaginary to real chemical potentials under conditions of strangeness neutrality. We scan the phase diagram and investigate whether these contours...
Rotation is known to restore chiral symmetry at high angular velocities, but it is also expected that rotation can induce an axial-vector condensate. This condensate, often overlooked, can significantly alter the behavior of the chiral condensate, potentially enhancing it under rapid rotation. To investigate this interplay, we compute the phase diagram of the chiral and axial vector...
The predictions of QCD at temperatures ranging from 1 GeV up to 160 GeV have recently become accessible from first-principles, non-perturbative lattice simulations owing to a novel computational strategy. Among the quantities that are being investigated in the ongoing program, hadronic screening masses - i.e. inverse correlation lengths - offer crucial insight into the properties of the QCD...
Stochastic hydrodynamics provides a dynamical framework for the evolution of fluctuations in heavy-ion collisions. Due to the small volume of the system, thermal fluctuations can become sizeable and probe the equation of state of the system, being particularly sensitive to a possible QCD critical endpoint.
Our present numerical setup can simulate stochastic non-relativistic hydrodynamics in a...
In this talk, I will present our latest research building upon the findings of PLB 850 (2024) 138533, which demonstrated that the entropy current can be derived from first principles using the quantum statistical method, bypassing the need for assumed traditional local thermodynamic forms. Our study uncovers that the local thermodynamic relations, which have been conventionally used as...
Heavy quarkonium serves as an excellent probe to study the properties of the Quark-Gluon Plasma (QGP). The physics of quarkonium created in heavy-ion collisions is intrinsically connected to the correlation functions of adjoint chromoelectric fields in quantum chromodynamics. Such correlation functions are vital in determining transport coefficients that govern the evolution of heavy...
We study the impact of asymmetric fermionic and bosonic dark matter on neutron star properties, including tidal deformability, maximum masses, radii, thermal evolution, moment of inertia, etc. The conditions under which dark matter particles tend to condense in the core of the star or create an extended halo are presented. We show that dark matter condensed in a core leads to a decrease of the...
We investigate the influence of nuclear structure on transverse spherocity ($S_0$) distributions in $^{238}U+^{238}U$ collisions at $\sqrt{S_{NN}}=193$ GeV. The initial spatial anisotropy of colliding nuclei is expected to imprint distinct signatures on final-state event topology. Hydrodynamic evolution translates these initial geometric anisotropies into momentum-space correlation via...
By consideration of the Compact object HESS J1731-347 as a hybrid twin compact star, i.e., a more compact star than its hadronic twin of the same mass, its stellar properties are derived. Besides showing that the properties of compact stars in this work are in good agreement with state-of-the-art constraints both from measurements carried out in laboratory experiments as well as by...
Major progress has been made in recent years toward computing the four-loop perturbative pressure of cold and dense quark matter (QM) [1,2], a key ingredient in constraining the equation of state of neutron-star matter. What remains to be computed is the contribution from hard-momentum gluons in dense QCD, encoded in the sum of 52 four-loop vacuum Feynman diagrams at finite baryon chemical...
Employing a kinetic framework, we calculate all transport coefficients for relativistic dissipative (second-order) hydrodynamics for arbitrary particle masses in the 14-moment approximation. Taking the non-relativistic limit, it is shown that the relativistic theory reduces to the Grad equations computed in the “order-of-magnitude” approach.
We propose a hybrid approach, which may help to establish consistency between different formulations of spin hydrodynamics. The perfect fluid is described in the framework of kinetic theory of particles with spin 1/2 following the Fermi-Dirac statistics. The baryon number, energy, linear momentum, the spin part of angular momentum, as well as entropy are conserved, although in the presence of...
Diffusion models are currently one of the leading generative AI approaches for image generation used by e.g. DALL-E and Stable Diffusion. A formulation familiar to physicists uses stochastic differential equations. We review this formulation and relate it to stochastic quantisation in quantum field theory. We demonstrate the approach for scalar and abelian gauge fields in two dimensions and...
In the last years, several exotic states have been observed in the charm sector; such particles cannot be interpreted as baryons or mesons and are thought to be either quark bags or molecular states. To unveil the nature of those states, it is crucial to experimentally constrain the strong force that governs the interaction between the charmed hadrons and other hadrons, e.g. via the...
In this work, we calculate the phase diagram of the (2+1)-dimensional Gross-Neveu-Yukawa (GNY) model under strong magnetic fields at finite temperature and density. Large magnetic fields result in magnetic catalysis, a dimensional reduction of the system and enhancement of the chiral symmetry breaking. Using the functional renormalization group (FRG) in a hydrodynamic approach allows us to...
The $\psi(3686)$ is identified as the radial excitation of the $J/\psi$. Based on perturbative QCD, the branching ratio of the $\psi(3686)$ into some final hadron state should be approximately 13\% of the branching ratio of the $J/\psi$ to that same hadron final state. This is called the "13\% rule". However, certain decay channels such as the $\rho\pi$ severely violate this 13\% rule. Using...
We explore the phase diagram of 8 flavor QCD by lattice simulations, using a stout improved staggered fermion action and a tree-level Symanzik improved gauge action. At small masses we observe an intermediate phase between the strong coupling and the weak coupling phases, aligning with results from previous studies. We also investigate the effect of adding an imaginary chemical potential.
We investigate the transport properties of quark matter under conditions of momentum anisotropy using the Polyakov chiral quark mean-field (PCQMF) model. Momentum anisotropy naturally arises in systems out of equilibrium, such as the early stages of relativistic heavy-ion collisions or the interior of compact stars. Understanding the impact of such anisotropy on transport coefficients is...
The chiral phase transition in (2+1)-flavor QCD is expected to be of second order, if the breaking of axial anomaly remains sufficiently strong at the chiral phase transition temperature $T_c$ [1]. This observation is supported by the lattice QCD calculations [2]. However, the FRG model calculations suggest that the scaling window may be small [3], within which the universal scaling relations...
The observation of significant Λ hyperon transverse polarization, i.e. the polarization in the direction transverse to the Λ production plane, in inclusive p+p and p+A collisions using unpolarized beams triggered theoretical efforts to describe this effect. Numerous models have been proposed to explain the origin of hyperon polarization. Several models have successfully explained the behavior...
In recent years, lattice QCD calculations have significantly advanced our understanding of the QCD phase diagram at finite temperature and baryon density. In this talk, I will discuss the QCD equation of state at finite baryon chemical potential, with particular emphasis on the Taylor expansion method used to extend lattice results to nonzero chemical potentials. I will highlight the role of...
In this talk, I will report our recent achievements based on ref. [1].
Quark-Hadron Continuity on QCD and Gauge-Higgs model
A big puzzle of QCD and its phase diagram is whether quark matter at high density and hadronic matter are smoothly connected or separated by the phase transition. On the one hand, since both phases have the same symmetry, the continuity between hadrons and quark...
The FASTSUM collaboration has a long-standing programme of using
anisotropic lattice QCD to investigate strong interaction
thermodynamics, and in particular spectral quantities. Here we
present first results from our new ensemble which has a temporal
lattice spacing $a_\tau=15$ am and anisotropy $a_s/a_\tau=7$, giving
unprecedented resolution in the temporal direction. We show...
We investigate the equation of state (EoS) of two-color QCD at low temperature and high density using lattice Monte Carlo simulations. Our results show that the speed of sound exceeds the relativistic limit (c^2_s/c^2= 1/3) after the BEC–BCS crossover in the superfluid phase. We also discuss the temperature dependence of the EoS within the superfluid phase. This talk is based on...
We discuss topology in Quantum Chromodynamics at high temperatures $T~\gtrsim~180$ MeV obtained from lattice simulations. Our setup consists of $N_f=2+1+1$ Wilson twisted mass fermions with physical quark masses and results are extrapolated to the continuum limit. We compare the results for the topological susceptibility obtained with the field-theoretic definition with those obtained from an...
The Equation of State of Quantum Chromodynamics with $N_f=3$ flavours is determined non-perturbatively with a precision of about 0.5%-1.0% in the range of temperatures between 3 GeV and 165 GeV. The computation is carried out by means of numerical simulations of the gauge theory discretized on the lattice. At each given temperature the entropy density is computed at several lattice spacings in...
Strong magnetic fields, attaining magnitudes comparable to the QCD scale, can significantly affect the equilibrium properties and bulk thermodynamics of strongly interacting matter. While such strong fields are expected in off-central heavy-ion collisions, directly measuring their imprints, such as chiral magnetic effects, remains challenging.
In this talk, we propose the baryon-electric...
We present BHAC-QGP, a numerical framework for simulating the evolution of quark-gluon plasma (QGP) in relativistic heavy-ion collisions under strong magnetic fields. Based on the general-relativistic magnetohydrodynamics code BHAC, originally developed for astrophysical applications, BHAC-QGP incorporates finite electrical conductivity and uses Adaptive Mesh Refinement (AMR) to capture QGP...
Relativistic hydrodynamics is the covariant generalization of a classical (non-relativistic, non-quantum) model. Recent developments in the field can explain how it is possible for relativistic hydrodynamics to be predictive in a very small system, in which quantum effects like diffraction and discrete (rather than continuous) spin states are not suppressed. This can be particularly...
We begin by using Hybrid Model calculations to reproduce experimental results published by ATLAS in 2023 on $R_{AA}$ for $R=1$ jets in Pb+Pb collisions. These jets are identified by first reconstructing anti-$k_t$ $R=0.2$ subjets and then re-clustering them. Following ATLAS, we investigate how $R_{AA}$ for these jets depends on the angle between the two subjets involved in the final clustering...
Dilepton emissions represent a key probe for characterising the Quark-Gluon Plasma (QGP). A central role in computing dilepton yields is played by the imaginary part of the electromagnetic current-current correlation, or equivalently, of the photon polarisation tensor [1]. In this work, we investigate the influence of local acceleration on dilepton production. We compute this quantity in a...
Analyzing the connections between the spin density matrix and the Wigner function for spin-half particles, we propose a new form of the local equilibrium Wigner function that solves the long-standing problem related to normalization of mean spin polarization. Interestingly, this new proposal for the local equilibrium Wigner function coincides with the recently developed generalized...
We build upon the recently formulated guiding-center kinetic theory for guiding-center plasma by incorporating spin degrees of freedom in the presence of electromagnetic fields. This approach yields a streamlined set of equations for guiding-center ideal hydrodynamics with spin--fewer than those in traditional spin hydrodynamics--owing to a restriction on motion perpendicular to the magnetic...
Hydrodynamic attractors were first studied in conformal Bjorken flow in the context of heavy ion collisions to discuss how the fireball of strongly interacting matter approaches hydrodynamic behaviour. Recently, a hydrodynamic attractor has also been constructed for the case of ultracold atom gases, meaning it now has a second real world application and may soon be measured directly in...
The search for the QCD critical point in heavy-ion collisions requires the inclusion of fluctuations in hydrodynamic simulations of Quark-Gluon Plasma (QGP). Schwinger-Keldysh Effective Field Theory (SK-EFT) systematically incorporates these fluctuations, extending beyond classical hydrodynamics, which accounts only for dissipation. After a brief review of SK-EFT, we discuss how linear...
Relativistic hydrodynamics has proven highly successful in describing the evolution of quark-gluon plasma in heavy-ion collisions. To account for event-by-event fluctuations in observables, especially those sensitive to the critical point, a framework of relativistic fluctuating hydrodynamics is required. We establish such a framework by introducing correlation functions for fluctuating...
