Recently the productions of exotic hadrons are interested not only for pp and ee collisions, but also for relativistic heavy ion collisions. The latter can be regarded as the factory for producing exotic hadrons from light to heavy flavors. Especially, the inner structures of exotic hadrons can be sensitive to the production process, and more information may be obtained by researching exotic...
The Coulomb gauge description of QCD is reviewed. How models can be built in this approach is described and example applications to mesons, glueballs, hybrids, hybrid decays, and hybrid mixing are discussed.
We study the nature of the hidden charm pentaquarks, i.e. the Pc(4312), Pc(4440) and Pc(4457), with a neural network approach in pionless effective field theory. In this framework, the normal fitting approach cannot distinguish the quantum numbers of the Pc(4440) and Pc(4457). In contrast to that, the neural network-based approach can discriminate them. In addition, we also illustrate the role...
Lattice QCD is the only known non-perturbative and gauge-invariant regularisation at present. The first-principles calculations of the lattice QCD based on the Monte Carlo methods have revealed various properties of QCD at low energies. In this lecture, the basics of Lattice QCD will be presented. As a final goal, I will discuss how hadron spectra are measured numerically.
Lattice QCD is the only known non-perturbative and gauge-invariant regularisation at present. The first-principles calculations of the lattice QCD based on the Monte Carlo methods have revealed various properties of QCD at low energies. In this lecture, the basics of Lattice QCD will be presented. As a final goal, I will discuss how hadron spectra are measured numerically.
I will discuss a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the Nπ states to these polarizabilities. Without considering these contributions, the lattice results fall significantly below the experimental values, consistent with previous lattice studies. This observation has motivated us to...
The application of the chiral Lagrangian to results from Lattice QCD simulations played an important role in the early days of the field when it was impossible to generate ensembles at the physical pion mass. With the tremendous improvement of hardware and simulation technologies it is now possible and rather wide spread to do simulations for selected physical quantities at sufficiently small...
The baryon masses on CLS ensembles are used to determine the LEC that characterize QCD in the flavor-SU(3) limit with vanishing up, down, and strange quark masses.[1,2]
Here we reevaluate some of the baryon masses on flavor-symmetric ensembles with much-improved statistical precision, in particular for the decuplet states. These additional results then lead to a more significant chiral...
Since 2003, many hadrons that do not fit into the conventional quark model of qqbar mesons and qqq baryons have been discovered experimentally. Because most (if not all) of these states are located at the thresholds of a pair of conventional hadrons, they have been conjectured to be hadronic molecules. There have been extensive theoretical and experimental studies to verify or refute the...
Some hadrons are hard to explain as normal hadrons made of quarks and antiquarks, or three quarks. These are called exotic hadrons. Since the Belle experiment reported $X(3872)$ in 2003, more exotic hadrons containing charm quarks have been found. Exotic hadrons are believed to have more complex structures than normal hadrons, but no conclusion has been reached yet.
The $X(3872)$ is one of...
Exotic hadrons are important subjects in the hadron physics. These states which lie slightly below the threshold have been expected to be hadronic molecules of two ordinary hadrons.
$T_{cc}$ was reported by the LHCb experiment in 2022 and this state is consistent with an isoscalar state whose $J$-parity is $1^+$. The Breit-Wigner mass relative to the $D^{\ast +}D^0$ threshold is...
In this presentation, we explore the low-energy behavior of $DD^*$ scattering phase shifts using twisted boundary conditions. While Lüscher’s method is typically employed to calculate scattering phase shifts between two hadrons from energy spectra, it becomes impractical to achieve high-resolution results using only periodic boundary conditions due to volume limitations. Conversely, twisted...
The properties of QCD matter in a strong magnetic field have attracted much attention because of their relevance to the physics of relativistic heavy-ion collisions and magnetars. For example, the effects of magnetic fields are intensely studied in both single-body and many-body problems, such as modifications of the hadron mass spectrum and the QCD phase diagram. On the other hand, recent...
We firstly employ the novel lattice EFT method to multi-hadron systems. The $DD^*K$ three-body system is taken as an illustration to demonstrate the great power of lattice EFT to hadron physics, especially the potential application for many-body systems. The sub two-body interactions are fixed by the $T_{cc}^+$, $D^{\ast}_{s0}(2317)$ and $D_{s1}(2460)$ states.
When the three-body interaction...
In this study, we present a lattice QCD analysis of the $J^P=1^+$
diquark within the charmed baryon $Σ_c^{++}(uuc)$.
Treating $Σ_c$ as a bound state of a charm quark and a uu $1^+$ diquark,
we utilize an extended HAL QCD potential method to determine both the
mass of the $1^+$ diquark and the potential between the charm quark and
the $1^+$ diquark.
Unlike the standard HAL...
The lattice QCD analysis of the HAL QCD Collaboration has recently derived
spin $ 3/2 $ $ N-\phi $ potential based on the $ \left({2+1}\right) $-flavor lattice QCD simulations near the physical point $m_{\pi}\simeq146.4$ MeV and $m_{K}\simeq525$
MeV on a large lattice space- time volume $\simeq\left(8.1\:{\textrm{fm}}\right)^{4}$.
We looked closely at phi-meson $ \left(\phi\right) $ and...
New measurements of the weak charge density distributions of $^{48}$Ca and $^{208}$Pb challenge existing nuclear models. In the post-PREX-CREX era, it is unclear if current models can simultaneously describe weak charge distributions along with accurate measurements of binding energy and charge radii. In this letter, we explore the parameter space of relativistic and non-relativistic models to...
We present the results of using the homotopy method to solve the nonlinear evolution equation for diffractive production in deep inelastic scattering (DIS). Initially, we introduce part of the nonlinear corrections as the first step in this approach. This allows for an analytical solution to the simplified nonlinear evolution equation, taking into account the initial and boundary conditions....
QCD governs the dynamics of quarks and gluons, and ultimately properties of hadrons and nuclei as well as nuclear astrophysical phenomena such as binary neutron star merges. Lattice QCD is the unique method which can solve QCD in a first-principle manner, and it can make predictions (or postdictions) for basic hadronic quantities.
The calculation of hadron interactions, however, is...
QCD governs the dynamics of quarks and gluons, and ultimately properties of hadrons and nuclei as well as nuclear astrophysical phenomena such as binary neutron star merges. Lattice QCD is the unique method which can solve QCD in a first-principle manner, and it can make predictions (or postdictions) for basic hadronic quantities.
The calculation of hadron interactions, however, is...
In this talk, I will first present the $D^*D$ scattering results obtained using $(2+1)$-flavor lattice QCD simulations with a nearly physical pion mass of $m_\pi=146$ MeV, which is crucial for understanding the first doubly charmed tetraquark $T^+_{cc}$. Next, I will discuss the left-hand cut singularity, which has been recently pointed out to be relevant for analyzing $T^+_{cc}$. Special...
The validity range of the time-honored effective range expansion can be very limited due to the presence of a left-hand cut close to the two-particle threshold. Such a left-hand cut arises in the two-particle interaction involving a light particle exchange with a mass small or slightly heavier than the mass difference of the two particles, a scenario encountered in a wide range of systems....
The strong interaction between nucleons has been at the heart of nuclear physics since the very beginning of this field. Remarkable progress has been achieved in recent decades towards quantitative understanding of nuclear forces and the corresponding current operators in the framework of chiral effective field theory. Combined with modern ab-initio few-body methods and continuously increasing...
The strong interaction between nucleons has been at the heart of nuclear physics since the very beginning of this field. Remarkable progress has been achieved in recent decades towards quantitative understanding of nuclear forces and the corresponding current operators in the framework of chiral effective field theory. Combined with modern ab-initio few-body methods and continuously increasing...
The two-particle momentum correlation function from high-energy nuclear collisions is beginning to be used to study hadron-hadron interaction. Because this observable is sensitive to the low-energy interaction, it is useful to study the nature of the near-threshold resonances and the underlying mechanism of the interaction. The meson-baryon and baryon-baryon interaction in strangeness sector...
Recently, femtoscopy in high-energy heavy-ion collisions has been gathering attention as a new approach to hadron-hadron interaction, and two-particle momentum correlation is widely measured in experiments [1]. Existing studies have mainly assumed the s-wave interaction, where the contributions from p-wave and d-wave have been neglected for simplicity. However, the correlation function gets...
Research on hypernuclei plays an essential role in answering how the hierarchy of nuclei is constructed from quarks. We are going to review the recent achievements in hypernuclear programs in J-PARC. One of the recent achievements is the realization of an accurate hyperon-nucleon scattering experiment. The differential cross sections of the Σ+p, Σ−p elastic scatterings and Σ−p → Λn inelastic...
The determination of hadron interactions is one of the most important subjects in nuclear physics, and the obtained interactions serve as the key quantities which bridge different hierarchies of physics, particle physics, nuclear physics and astrophysics.
Recently, a novel theoretical method (HAL QCD method) was proposed to calculate hadron interactions from first-principles calculations by...
Understanding (hyper)nuclear physics from ab initio QCD has been a long-standing goal. By calculating finite-volume spectra on the lattice and using finite-volume quantization conditions, it is possible to determine baryon-baryon scattering phase shifts and bound states. I will discuss the challenges in these calculations, presenting results in the continuum limit at an SU(3) flavour-symmetric...
An introductory overview will be given summarizing various aspects of the QCD phase diagram, with special emphasis on cold dense matter as it is realised in neutron star centers. This includes state-of-the-art results from Bayes inference of observational data. Also included are theoretical considerations at the scales relevant to neutron star physics: spontaneously broken chiral symmetry of...
An introductory overview will be given summarizing various aspects of the QCD phase diagram, with special emphasis on cold dense matter as it is realised in neutron star centers. This includes state-of-the-art results from Bayes inference of observational data. Also included are theoretical considerations at the scales relevant to neutron star physics: spontaneously broken chiral symmetry of...
There are many examples of correlations among neutron star properties and parameters of the dense matter equation of state near the saturation density. Motivated by the discovery of correlations among the neutron star maximum mass, its radius, central density and pressure, and perturbative expansions in radius of the mass, energy density and pressure near the centers of neutron stars, a...
In most equations of state, the electron chemical potential in neutron star (NS) matter reaches the value of the free pion mass at rather moderate baryon densities. This would lead to pionization of NS matter when negative pions replace electrons. The repulsive s-wave pion-neutron interaction could prevent this.
We apply the effective chiral Lagrangian at the second chiral order to construct...
Nonrelativistic bound states lie at the core of quantum physics, permeating the fabric of nature across diverse realms, spanning particle to nuclear physics, and from condensed matter to astrophysics. These systems are pivotal in addressing contemporary challenges at the forefront of particle physics. Characterized by distinct energy scales, they serve as unique probes of complex environments....
Nonrelativistic bound states lie at the core of quantum physics, permeating the fabric of nature across diverse realms, spanning particle to nuclear physics, and from condensed matter to astrophysics. These systems are pivotal in addressing contemporary challenges at the forefront of particle physics. Characterized by distinct energy scales, they serve as unique probes of complex environments....
In the last years the correlation measurements at LHC, particularly performed in small colliding systems such as proton-proton collisions, proved to be a powerful complementary experimental tool to access the strong interaction in hadronic systems with strange and charm content. The QCD dynamics driving the underlying interaction in these sectors is characterized by a rich presence of...
In this work, to calculate the diquark mass together with the quark-diquark potential, we apply an extended HAL QCD potential method to a baryonic system made up from a static quark and a diquark where we consider various types of diquarks (eg: scalar $0^{+}$ diquark, axial-vector $1^{+}$ diquark etc). Numerical calculations are performed employing 2+1 flavor QCD gauge...
The gravitational form factors of the proton provide essential information on its mechanical structure such as its mass, spin, mechanical pressure, and shear force. In the current talk, we present a series of recent results for the flavor decomposition of the gravitational form factors~(GFFs) of the proton in a pion mean-field approach or the chiral quark-soliton model. We analyze problems...
Pion and kaon are one of the simplest meson structures to study the distribution function. In this work, we have calculated the time reversal quark transverse momentum-dependent parton distribution functions (TMDs) in the light-front based holographic model (LFHM) and quark model (LFQM) up to twist-4. We have presented the three dimensional structure of T-even TMDs for both the particles in...
Understanding how hadrons are made by quarks and gluons from Quantum Chromodynamics (QCD), the underlying theory of strong interaction, is a holy grail in theoretical physics. I will review where we are in this quest 10 years after the invention of the Large Momentum Effective Theory.
The strong coupling alpha_s is a fundamental parameter of the Standard Model and high accuracy at the 0.5 percent level or better will be required to maximize the potential of the LHC and other experiments.
Lattice QCD is ideally placed to achieve this goal. As a member of the FLAG working group on alpha_s I present an update of the current situation and an outlook on future prospects.
In this talk I will show how the BOEFT, derived from Quantum Chromodynamics on the basis of scale separation and symmetries, can address XYZ exotics of any composition. We derive the Schr ̈odinger coupled equations that describe hybrids,tetraquarks, pentaquarks, doubly heavy baryons, and quarkonia at leading order, incorporating nonadiabatic terms, and present the predicted multiplets. We...
Near-threshold exotic hadrons are studied actively. In order to understand the nature of them, it is necessary to determine the scattering length from experimental data, because the scattering length governs the near-threshold scatterings. The cusp structure of cross sections reflects the value of the scattering length. In this work, we study the behavior of threshold cusp in multi-channel...
We propose a chiral quark model including the ω and ρ meson contributions in addition to the π and σ meson contributions. We show that the masses of the ground state baryons such as the nucleon, Λc and Λb are dramatically improved in the model with the vector mesons compared with the one without them. The study of the tetraquark Tcc is also performed in a coupled channel calculation and the...
In recent experiments in the heavy quark sector, various candidates of exotic hadrons have been observed. Most of exotic hadrons are discovered near the threshold of two-body scattering as represented by $T_{cc}$ and $X(3872)$ [1,2]. Such near-threshold states are empirically considered as hadronic molecules [3]. To focus on the molecular structure, it is useful to calculate the compositeness,...
We discuss quantitative evaluation of chiral condensate in nuclear medium based on high-precision experimental information of pionic atoms. We made spectroscopy of deeply bound pionic Sn 121 atoms and determined the binding energies and the widths of the pionic orbitals. We deduced pion-nucleus interaction to evaluate the chiral condensate at nuclear saturation density, which was found to be...
We perform a numerical study in lattice QCD on $\Lambda(1405)$ in the flavor SU(3) limit. One of the most promising interpretations of $\Lambda(1405)$ is the so-called two-pole structure: the spectrum corresponding to $\Lambda(1405)$ observed in experiments may be explained by two poles. In order to elucidate such property from lattice QCD, the HAL QCD method is employed, in which hadron...
In this talk, I will present recent developments in heavy quark dibaryons and QCD matter under extreme conditions. There has been significant interest recently in studying heavy quark exotic states, particularly with numerous lattice QCD calculations focusing on tetraquarks. Additionally, there have been multiple studies on dibaryons containing heavy quarks.
I will focus on two recent...
Low-energy nuclear structure and reactions can be described in a systematically improvable way using the framework of chiral EFT. This requires solving the quantum mechanical many-body problem with regularized nuclear interactions, derived from the most general effective chiral Lagrangian. To maintain the chiral and gauge symmetries, a symmetry preserving cutoff regularization has to be...
There have been rapid developments in the direct calculation in lattice QCD (LQCD) of the Bjorken-$x$ dependence of hadron structure through large-momentum effective theory (LaMET) and other similar effective approaches. These methods overcome the previous limitation of LQCD to moments (that is, integrals over Bjorken-$x$) of hadron structure, allowing LQCD to directly provide the kinematic...
Simulating QCD in the traditional way on very large lattices leads to conceptual and technical issues with impact on performance and reliability. In view of the new master-field framework, simulations with dynamical fermions are particularly challenging. The proposed stabilising measures comprise algorithmic changes as well as a new O(a)-improved Wilson action with exponential clover term.
In...
We discuss the RBC/UKQCD calculation of two-pion scattering at physical pion and kaon masses. Recent RBC/UKQCD results for related topics such as $K\to\pi\pi$ decay and long-distance HVP contribution to muon $g-2$ will also be presented.
It has been demonstrated that distillation profiles can be employed to build optimised quarkonium interpolators for spectroscopy calculations in lattice QCD. The use of optimal profiles increases the overlap with the ground state significantly and grants access to excited states, for multiple quantum numbers. After reviewing the method, we report exemplary results on the low-lying charmonium...
Many candidates of exotic hadrons have recently been found near the two-body threshold of hadronic channels. As an example, there have been studies predicting a near-threshold bound state or virtual state in the DbarN system. In this talk I will show the latest results of the DbarN interaction simulated by the HALQCD method near the physical point and discuss its consequences.
I also plan...
We show the production systematics of open charm hadron yields in high-energy collisions and their description based on the Statistical Hadronization Model. The rapidity density of $D^0, D^+, D^{*+}, D_s^+$ mesons and $\Lambda_c^+$ baryons in heavy ion and proton-proton collisions is analyzed for different collision energies and centralities.
The Statistical Hadronization Model is extended...
The Worldvolume Hybrid Monte Carlo (WV-HMC) method [arXiv:2012.08468] is a reliable and versatile algorithm for solving the sign problem. This method eliminates the ergodicity problem inherent in methods based on Lefschetz thimbles at low cost. In this talk, I will report recent results on the application of the WV-HMC method to lattice field theories. The discussion will focus on the Hubbard...
The femtoscopy technique has been recently used at the Large Hadron Collider to perform new studies on hadronic interactions in few-body systems. The method exploits high-energy collisions as sources of hadrons and analyse the momentum correlation among the emitted particles to pin down the effects induced by their final state interaction. The interpretation of three-particle correlation...
$\Omega-^{4}He (\alpha) $ two-particle momentum correlation functions are studied.
Such correlations as an alternative source of information can help us further understand the interaction between $ \Omega $ and nucleons (N).
$\Omega-\alpha $ potentials in the single-folding potential approach are constructed by employing two differents state-of-the-art $\Omega-N $ interactions in...
Understanding the non-perturbative confinement regime of quantum chromodynamics (QCD) necessitates identifying states within the hadronic spectrum. Recently, numerous new states have been discovered by various experimental collaborations. However, not all observed signals correspond to excitations of low-lying hadrons. Rigorous amplitude analysis techniques are essential to determine which...
In this study, we delve into nuclear forces governed by Quantum Chromodynamics (QCD) utilizing the HAL QCD method alongside Femtoscopy. These methodologies offer valuable insights into hadron-hadron interactions derived from Lattice QCD simulations and empirical data from collision experiments. I will present our approach of using neural networks to model potential functions, which are learned...
An elementary argument suggests that for the chiral phase transition, if the interactions which violate the anomalous axial $U(1)_A$ symmetry are induced by instantons, then for three flavors, the chiral transition is inescapably of first order in the chiral limit. Numerical simulations on the lattice indicate that the first order region is much smaller than expected. I consider the...
We mathematically show an equality between the index of a Dirac operator on a flat continuum torus and the $\eta$ invariant of the Wilson Dirac operator with a negative mass when the lattice spacing is sufficiently small. Unlike the standard approach, our formulation using the $K$-theory does not require the Ginsparg-Wilson relation or the modified chiral symmetry on the lattice. We prove that...
We report on the ongoing study of symmetry of $N_f=2$ QCD around the critical temperature. Our simulations of $N_f=2$ QCD employ the Mobius domain-wall fermion action with residual mass $\sim 1\mbox{MeV}$ or less, maintaining a good chiral symmetry. Using the screening masses from the two point spatial correlators we compare the mass difference between channels connected through symmetry...
We propose a new method to use Lee-Yang zeros to search for a critical point in numerical analyses. We show that the ratios of the Lee-Yang zeros calculated on various spatial volumes have a crossing at the critical parameter. We find that this property allows us to determine the location of a critical point that appears in a model in a straightforward manner. The method is adopted to locate...
Symmetry is one of the most fundamental principles in nature, but where does it come from? I will discuss recent efforts to understand origin of symmetry from the perspective of quantum information and consider two very different physical systems with emergent symmetries. The first involves non-relativistic neutron-proton scattering in low-energy QCD, where the suppression of spin entanglement...
While the phi meson vacuum properties, such as mass and width, are well known, it is not clear how these properties will change once it is put in a dense environment such as nuclear matter. To study how the phi meson behaves at finite density has been the goal of several past and near future experiments at KEK, COSY-ANKE and J-PARC. Recently, ALICE has also obtained novel experimental data...
Observations of the heaviest neutron stars, together with mass and radius measurements and gravitational wave signals from binary neutron star mergers, progressively tighten the constraints on the equation-of-state of dense baryonic matter. Using the presently available observational data base, results are presented of detailed Bayes inference analyses. A focus is on prerequisites and...
I will discuss quark mass-dependent operators in the Chiral Perturbation Theory, their effects on the equation of state of dense matter, and their implications for astrophysics. I highlight how these operators influence three-body forces and the possibility of pion and axion condensation in neutron stars.
The hyperon puzzle of neutron stars refers to the problem that most of the equations of state with hyperons are not sufficiently stiff to support the observed massive neutron stars. One promising solution to the puzzle is that the three-body forces between a hyperon and medium nucleons produces such strong repulsion that $\Lambda$'s do not appear in neutron stars. The $\Lambda$ single-particle...
We discuss the interplay between two first-principles calculations of QCD at high density: perturbative results in the weak-coupling regime and the recent lattice-QCD result at finite isospin density. By comparing these two results, we verify empirically that the weak-coupling calculations of the bulk thermodynamics and the gap parameter for Cooper pairing between quarks can be applicable down...
In many-body systems where continuous symmetry is spontaneously broken, gapless Nambu-Goldstone modes emerge, significantly influencing low-energy real-time dynamics. These dynamics are best described by hydrodynamic equations that incorporate the effects of these Nambu-Goldstone modes. In this talk, I will present a thermodynamic framework for deriving such hydrodynamic equations in...
By taking the nucleon-to-quark phase transition within a neutron star as an example, we present a thermodynamically consistent method to calculate the equation of state of ambient matter so that transitions that are intermediate to those of the familiar Maxwell and Gibbs constructions can be described. This method does not address the poorly known surface tension between the two phases...
What does the phase diagram of matter, such as matter in the interior of neutron stars, look like? How does matter evolve and thermalize after energetic processes such as after the Big Bang or in particle colliders? How do quarks and gluons and their interactions give rise to the complex structure of a proton or a nucleus, and their response to various probes? A successful lattice...
Gauge theories are fundamental to various areas of physics. In high-energy physics, the standard model, which is a gauge theory, explains three of the four fundamental forces of nature. While at high-energy scales quantum chromodynamics can be addressed perturbatively, this approach becomes ineffective at lower energies, necessitating nonperturbative techniques. This naturally leads to the...
Tensor renormalization group is expected to be a promising method to simulate lattice field theories at finite density since it does not suffer from the sign problem. We construct a Grassmann tensor network representing the partition function of 1+1D SU(2) lattice gauge theory coupled with staggered fermions. At finite couplings, a random sampling is applied to discretize the group...
We propose a new analytical nonperturbative formalism, in whcih a
dispersion relation obeyed by a correlation function is treated as an
inverse problem. Given the operator product expansion of the
correlation function in the deep Euclidean region as inputs, we solve
for resonance properties at low energy directly from the dispersion
relation. We demonstrate the power of this approach by...
Recent results on the QCD equation of state (EoS) with 2+1+1 flavors of highly improved staggered quarks (HISQ) are presented. The trace anomaly is computed on ensembles with temporal extent 6, 8, 10 and 12. The pressure is reconstructed from the trace anomaly with the integral method. The available temperature range extends up to about 960 MeV on the coarser ensembles. Along the line of...
I will shortly review recent lattice QCD results on the bulk thermodynamics of QCD at finite temperature and baryochemical potential. I will discuss calculations of the equation of state and fluctuations of conserved charges. I will also comment on the search for the coveted critical endpoint of QCD.
Three-body nuclear forces are essential for explaining the properties of light nuclei with a nucleon number greater than three. Building on insights from nuclear physics, we extract the form of quark three-body interactions and demonstrate that these terms are crucial for extending the quark model fit of the meson spectrum to include baryons using the same parameter set. We then discuss the...
Lattice constraints on the QCD phase diagram
A strong fermion sign problem prohibits direct lattice simulations of QCD at finite baryon density, so that knowledge of the phase diagram is limited to small chemical potentials. On the other hand, the phase diagram is severely constrained by information about the chiral limit.
I discuss recent lattice results at vanishing density, which show...
The LHC experiment has provided valuable insights into how charm and beauty quarks hadronize into various mesons and baryons under different collision systems. Contrary to our initial assumption that charm quarks hadronize independently of the collision system, with a universal fragmentation function that can be empirically parameterized, the LHC measurements suggest that additional...
We explore the phase diagram of (2+1)-flavour QCD through the fluctuations of conserved charges calculated with Möbius domain-wall Fermions (MDWF). We present quark number susceptibilities and conserved charge fluctuations at pion masses around 220 MeV and 135 MeV for aspect ratios of lattices LT=2 and LT=3, respectively. Results are compared with the previous works by HotQCD and...
Gravitational waves from binary-neutron-star mergers enable us to observe accurately the orbital evolution and postmerger dynamics. On the one hand, the orbital evolution tells us about intermediate-density matter characterizing premerger neutron stars. On the other hand, postmerger dynamics may reflect how hadrons transition to quarks at high density. In this talk, I will discuss the current...
In this talk, I discuss the statistically determined equation of state of dense matter that fulfills the multimessenger constraints and determine the properties of dense matter found in neutron stars. I demonstrate that the speed of sound and trace anomaly are driven towards their conformal values at the center of maximally massive NSs. I argue that the local peak of the speed of sound is...
Recent advances in multi-messenger astronomy have provided a key set of constraints on the equation of state (EoS) of QCD at high baryon density, via extraterrestrial observations of dense stellar objects such as neutron stars (NSs). It was suggested that the softening of the EoS at intermediate densities required to comply with the observed tidal deformability, together with the subsequent...
Elucidation of the QCD phase structure is an important topic in particle and nuclear physics. We construct a four-dimensional equation of state as a function of the temperature and the chemical potentials of net baryon (B), charge (Q), and strangeness (S) for the QCD matter created in nuclear collisions [1]. Lattice QCD simulations and a hadron resonance gas model are considered for the...
In this talk, I will introduce dense baryonic matter in the Sakai-Sugimoto (SS) model, a popular variant of holographic QCD, using a homogeneous Ansatz for isospin symmetric matter and then for nonvanishing isospin chemical potential. I will also show that the isospin contribution to the energy, directly proportional to the symmetry energy, can be computed formally as a moment of inertia of...
We derived equations of state for neutron stars using a bottom-up holographic QCD model. Our calculations include mass-radius relationships of neutron stars and the sound velocity in high-density QCD matter. We also obtained partial restoration of chiral symmetry in finite baryon density.
Two-color ($N_c=2$) QCD world is one of the useful testing grounds to delineate cold and dense QCD matter, since the lattice QCD simulation is straightforwardly applicable thanks to the disappearance of the sign problem. Motivated by recent numerical results from the lattice QCD activities, I am being investigating properties of dense two-color QCD by constructing the linear sigma model (LSM)....
The recent discovery of a central compact object (CCO) within the supernova remnant HESS J1731-347, characterized by a mass of approximately $0.77^{+0.20}_{-0.17} M_{\odot}$ and a radius of about $10.4^{+0.86}_{-0.78}$ km, has opened up a new window for the study of compact objects. This CCO is particularly intriguing because it is the lightest and smallest compact object ever observed,...
We study the effect of the isovector-scalar meson $a_0$(980) on the properties of nuclear matter and the neutron star (NS) matter by constructing a parity doublet model with including the $a_0$ meson based on the chiral SU(2)$_L\times$SU(2)$_R$ symmetry.
We also include the $\omega$-$\rho$ mixing contribution to adjust the slope parameter at the saturation.
We find that, when the chiral...
Breakthroughs in our treatment of nuclear forces constrained by QCD, the many-body problem, and AI/machine learning techniques are transforming modern nuclear theory into a true first-principles discipline. This allows us to now address some of the most exciting questions at the frontiers of nuclear structure, searches for physics beyond the standard model, and connections to nuclear...
Two recent applications of generative machine learning models to neutron star physics will be presented.
i) An anomaly detection framework based on normalizing flows (NF) models to detect the presence of a large (destabilizing) dense matter phase transition in neutron star (NS) observations of masses and radii, and relate the feasibility of detection with parameters of the underlying...
At finite densities of three-flavor QCD, a hadron (confinement) superfluid phase is expected to be realized at low densities, and a color superconducting (Higgs) phase at high densities. It is not well understood whether these two phases are connected with or without a phase transition. In this talk, we consider the Higgs-confinement transition with superfluidity in a $\mathrm{U}(1) \times...
A fermion representation with exact chiral symmetry can be obtained on a 5-dimensional lattice with a single boundary, circumventing the Nielsen-Ninomiya theorem. I discuss this as well as a proposal for gauging the theory, and objections that have been raised.
In the standard lattice domain-wall fermion formulation, two flat domain-walls are put where both of the left- and right-handed massless modes appear on the walls. In this work we investigate a single spherical domain-wall fermion mass term embedded into a flat square three-dimensional lattice. In the free fermion case, we find that a single Weyl fermion appears at the wall and it feels...
We discuss a single domain-wall system with a nontrivial curved background by considering a massive fermion on a 3D square lattice, where the domain-wall is a 2D sphere. In the presence of a topologically nontrivial U(1) link gauge field, we observe the emergence of a zero mode with opposite chirality localized at the center where the gauge field is singular. This results in the low-energy...
I'll discuss a Monte Carlo and analytic exploration of some simple lattice models that feature persistent order, namely that they are in an ordered phase at all temperatures. These models have BKT-like phase transitions that separate regions with spontaneous symmetry breaking and CFT phases. Understanding how to study such systems using Monte Carlo methods is a first step toward the study of...
Recently, lattice formulations of Abelian chiral gauge theory in two dimensions have been
devised on the basis of the Abelian bosonization. A salient feature of these 2D lattice for-
mulations is that the gauge invariance is exactly preserved for anomaly-free theories and thus
is completely free from the question of the gauge mode decoupling. In the present paper, we
propose a yet another...
CP(N-1) models in (1+1)-d have a global SU(N) symmetry and share many features with QCD. They are asyptotically free, have a non-perturbatively generated mass gap, and non-trivial theta-vacuum states. CP(N-1) models can be regularized unconventionally by using discrete SU(N) quantum spins forming a (2+1)-d spin ladder that consists of n transversely coupled quantum spin chains. The (1+1)-d...
I will discuss theories with the $Z_N$ 1-form symmetry and argue that theories in 4d generically have three phases: the spontaneously broken phase, the restored (confined) phase and the coulomb phase. Natural string-like objects appear in this analysis, which we associate with the center vortices of the corresponding $SU(N)$ gauge theory. In addition the discussion also reveals particle-like...
The two promising scenarios for quark confinement are monopole and center-vortex mechanisms. These mechanisms are realized in the weakly coupled semiclassical frameworks: monopole semiclassics on $\mathbb{R}^3 \times S^1$ and center-vortex semiclassics on $\mathbb{R}^2 \times T^2$. In this presentation, we will bridge two semiclassical descriptions, illustrating how the BPS and KK monopoles...
We will discuss general aspects of charge conjugation symmetry in Euclidean lattice field theories including its dynamical gauging. As an application, we construct O(2) gauge theory on the lattice using a non-abelian generalization of the Villain formulation. This lattice discretization preserves a myriad of generalized global symmetries of the continuum theory, and we describe how to...
A long standing problem in lattice QCD is to naturally define the Yang-Mills instanton on the lattice. I will show how this problem is, and has to be, resolved by higher category theory.
To resolve the problem, the notion of lattice Yang-Mills must be refined at a conceptual level, in a way similar to how Villainization refines XY model and $U(1)$ lattice gauge theory. The remarkable...
In this talk, I will discuss metastable vacua of 2d $\mathbb{C}P^{N-1}$ model in the large $N$ limit.In particular we will focus on the theta angle dependence of the metastable vacuum energy.We will see the vacua become unstable at large theta angles due to high decay rates.This work is in collaboration with Tsubasa Sugeno and Kazuya Yonekura.
Simulating dynamical properties of non-abelian gauge theories is considered to be an ideal target for quantum computers.
In this talk, I will present recent progress toward simulating a confining flux string and its breaking due to creation of dynamical charges in a minimal setup. Our proposal is based on a q-deformed formulation of SU(2) lattice gauge theory, truncating the gauge group to...
Full-fledged Quantum computation/simulation of lattice QCD is a long-term goal and requires developing a set of strategies starting from foundational level. This includes a convenient Hamiltonian framework for the theory along with the Hilbert space construction compatible with the principle of gauge invariance. The recently developed Loop-string-hadron approach is a promising framework for...
Quantum electrodynamics in 1+1 dimensions (the Schwinger model) exhibits a number of features similar to quantum chromodynamics in 3+1D, including confinement and a fermion condensate, making it the perfect sandbox during the NISQ era. In this talk, I will present new scalable algorithms that use the symmetries and hierarchy of length scales in the Schwinger model (and generally applicable to...
We present a couple of methods to compute the mass spectra of composite particles (hadrons) in gauge theories,
which can be implemented in quantum computing or tensor networks in the Hamiltonian formalism.
The hadron mass can be efficiently computed from the one-point function, combining the correlation function to deal with the operator mixing.
Alternatively, we can obtain the dispersion...
Current noisy quantum computers can be already used to investigate properties of quantum systems. Here we focus on lattice QED in (2+1)D including fermionic matter.
This complex quantum field theory with dynamical gauge and matter fields has similarities with QCD, in particular asymptotic freedom and confinement.
We define a suitable setup to measure the static potential between two static...
We review recent proposals to quantum simulate lattice gauge theories with configurable arrays of Rydberg atoms. We discuss possible implementations with remote access of facilities open to the general public. We discuss new methods to measure the entanglement entropy using a single copy of quantum systems.
We demonstrate the steps to study the dynamics of a field theory model using a digital computer, with an example of the SYK model. We present calculations on IBM's superconducting quantum computer and state-of-the-art results using various error mitigation techniques. Specifically, we compute the vacuum return probability and out-of-time-order correlators (OTOC) at different times, standard...
Motivated by recent developments in quantum computing, many efforts have been devoted to exploring their potential applications in high-energy physics, particularly in simulation of lattice gauge theories. However, the capability of present quantum computers is very limited due to noise, and simulating the physics problems is still challenging. In this presentation, we talk about a digital...
Complex quantum many-body dynamics spread initially localized quantum information across the entire system. Information scrambling refers to such a process, whose simulation is one of the promising applications of quantum computing. We demonstrate the Hayden-Preskill recovery protocol and the interferometric protocol for calculating out-of-time-ordered correlators to study the scrambling...
Quantum computers offer a promising new approach to studying real-time dynamics, which remains challenging for traditional methods like Monte Carlo simulations and tensor networks. In this talk, I will present progress on two key areas: simulating particle scattering and calculating parton distribution functions (PDFs) in 1+1 dimensions using digital quantum computing.
We propose a setup to...
Relativistic hydrodynamics has been used to study collective behavior of light particles produced in heavy ion collisions. It has been shown that hydrodynamic calculations with a small shear viscosity give results that agree well with experimental data. Furthermore, a holographic calculation showed that the ratio of shear viscosity and entropy density is as small as 1/(4pi) for strongly...
Quantum mechanical theories have an underlying convex geometry defined by the fact that the Hilbert-space norm is positive definite. Positivity is a surprisingly strong constraint, which when combined with other information (such as lattice data, Schwinger-Dyson relations, or equations of motion), allows one to establish qualitatively tight bounds on the behavior of many quantum systems,...
I discuss a quantum algorithm to compute the logarithm of the determinant of the staggered fermion matrix, assuming access to a classical lattice gauge field configuration. The algorithm uses the quantum eigenvalue transform, and quantum mean estimation, giving a query complexity that scales like O(V log(V)) in the matrix dimension V.
The infinite-dimensional Hilbert space of SU(3) gauge field makes the quantum simulation of QCD difficult. In this talk, I would like to propose Z3 lattice gauge theory as a toy model with the finite-dimensional Hilbert space. I will discuss the similarity and difference compared with QCD and the application to quantum simulation.
Non-abelian gauge theories play a pivotal role in our description of the universe, from low to high-energies, but their complexity hinders our understanding of their emergent phenomena. In this talk, we will consider a one-dimensional SU(2) lattice gauge theory with dynamical matter, the simplest theory supporting the existence of baryons and mesons. We will show how to build a quantum...
Real-time dynamics of Quantum Chromodynamics and other strongly coupled gauge theories present significant challenges for standard Monte Carlo methods due to severe sign problems. This limitation makes these problems ideal candidates for quantum simulation techniques. Identifying phenomena that can be tackled using near-term quantum simulators is crucial for understanding real-time dynamics in...
The recent advancements towards scalable fault-tolerant quantum computing have brought excitement about simulating lattice gauge theories on quantum computers. However, digital quantum computers require truncating the infinite-dimensional link Hilbert space to finite dimensions. In this talk, we focus on the $\mathrm{SU}(N)$ gauge theory coupled to $N_f$ flavor of quarks and propose a...
