Instantons, Holography, Strong Interactions and Nuclear Physics
Conference 2023 at Henan University
This conference aims at bringing together people from various areas of
physics to learn new methods, get new inspiration and finding new interesting problems to work on.
Low energy physics has faced the problems of strong coupling in the
QCD sector of the standard model, since the standard model was
established as the correct fundamental theory of physics.
Almost all nuclear physics models are phenomenological and data-driven
and do not "know anything" about QCD, directly.
Holographic methods have been developed in many groups in the past
couple of decades, but often in parallel with nuclear physicists’ work
with little communication between the communities.
The chiral Lagrangian has a geometric description of nuclei in terms
of Skyrmions, which are instantons in holographic models, like the
Witten-Sakai-Sugimoto model and this approach, in principle, fixes all
low-energy constants (LEC) in nuclear physics.
An alternative and possibly equivalent way to fix the LECs is by assuming hidden local symmetry.
The extraction of the nucleon-nucleon potential from such a model has
been nontrivial and has only been done successfully very recently.
Hopefully, this conference will provide an atmosphere for discussion
of many topics, and lead to new ideas and methods.
Markus Amano (河南大学)
Lorenzo Bartolini (河南大学)
Stefano Bolognesi (意大利比萨大学)
Josh Cork (英国莱斯特大学)
Chris Halcrow (瑞典皇家理工学院)
||Sven Bjarke Gudnason (summary)
(Henan University) - Modes of the Sakai Sugimoto SolitonAbstract→The instanton in the Sakai-Sugimoto model corresponds to the Skyrmion on the holographic boundary - which is asymptotically flat - and is fundamentally different from the flat Minkowski space Yang-Mills instanton. We use the Atiyah-Patodi-Singer index theorem and a series of transformations to show that there are 6k zeromodes - or moduli - in the limit of infinite 't Hooft coupling of the Sakai-Sugimoto model. The implications for the low-energy baryons - the Skyrmions - on the holographic boundary, is a scale separation between 2k "heavy" massive modes and 6k-9 "light" massive modes for k>1; the 9 global transformations that correspond to translations, rotations and isorotations remain as zeromodes. For k=1 there are 2 "heavy" modes and 6 zeromodes due to degeneracy between rotations and isorotations.
(国科大杭州高等研究院) - Baryons as Vortexes on the η' Domain WallAbstract→We demonstrate that the recent construction of N_f=1 baryons on the η' domain wall can be understood as vortexes of the principal effective theory on a 2+1-dimensional sheet. Essentially, this effective theory is identified as a complex scalar with a Higgs-type potential that is minimally coupled with the Level-N_c Chern-Simons theory, namely the Chern-Simons-Higgs theory. This theory has a series of vertex solutions, and the basic vortex carries unit topological charge and naturally spins N_c/2, which coincides with the one-flavor baryon. By virtue of the particle-vortex symmetry, the dual Zhang-Hansson-Kivelson theory indicates that the quark carrying 1/N_c topological charge and obeying fractional statistics. The generalization to arbitrary N_f is discussed.
(Henan University) - Neutron Stars and Isospin Asymmetric Nuclear Matter from HolographyAbstract→Description of nuclear matter in the core of neutron stars eludes the main tools of investigation of QCD, such as perturbation theory and the lattice formulation of the theory. Recently, the application of the holographic paradigm (both via top-down and bottom-up models) to this task has led to many encouraging results, both qualitatively and quantitatively. In this talk, we will present our approach to the description of neutron star cores, relying on a simple model of the (double) hard-wall type: we will discuss results concerning the nature of homogeneous nuclear matter at high density emerging from the model including a quarkyonic phase, the mass-radius relation for neutron stars, as well as the rather stiff equation of state we have found.
Moreover, we introduce a "Skyrmion inspired" quantization scheme for the Isospin quantum number, and we employ it to compute the symmetry energy of dense nuclear matter in both the (double) Hard-wall and the Witten-Sakai-Sugimoto models.
(Pisa University) - A class of strongly coupled chiral gauge theoriesAbstract→We study the dynamics of SU(N) chiral gauge theories with massless fermions belonging to various combinations of the symmetric, antisymmetric or fundamental representations. We limit ourselves to the gauge-anomaly-free and asymptotically free systems. 't Hooft anomaly-matching conditions severely limit the possible RG flows. In vectorlike theories such as the quantum chromodynamics, gauge-invariant ``quark-antiquark" condensates form and characterize the IR dynamics, and the anomaly matching involves the Nambu-Goldstone bosons. In some other special cases, such as the Bars-Yankielowicz (BY) or Georgi-Glashow (GG) models, a hypothetical solution was proposed in the literature, with no global symmetry breaking and with some simple set of composite massless fermions saturating all the anomalies. For the BY and GG systems, actually, a more plausible candidate for their IR physics is the dynamical Higgs phase, with a few simple bi-fermion color-flavor locked condensates.
(中国科学院大学) - First order phase transition and dynamic critical phenomena in holographyAbstract→First order phase transitions are very common phenomena in our real world. In this talk, I will introduce a universal physical picture of first order phase transitions, which can be most clearly seen from holography (applied AdS/CFT). This picture can be made precise by the so-called landscape, from which we can understand why critical behaviors are ubiquitous in systems with first order phase transitions, where the inhomogeneous cases are of special interest.
(Jiangxi Normal University) - N-particle irreducible actions for stochastic fluids Abstract→We present our work on constructing effective actions for stochastic fluid dynamics of a conserved density undergoing diffusive motion. We focus on the 1PI and 2PI actions, which we compute at one-loop and two-loop approximations, respectively. After solving the Schwinger-Dyson equations numerically for a non-critical fluid, we reveal that higher-loop effects lead to the renormalization of the non-linear coupling. In sum, our findings provide important insights into the behavior of conserved densities in stochastic fluid dynamics.
(Leicester University) - ADHM skyrmionsAbstract→Finding a suitable space on which to model all skyrmion configurations is a long-standing problem in the Skyrme model. We propose, via the Atiyah-Manton construction, that the moduli space of ADHM data for instantons is such a space; it provides enough controlled degrees of freedom to describe coalesced highly-symmetric configurations, as well as skyrmion clusters and paths between configurations. In this talk I shall discuss the key methods involved in the construction of skyrmions from ADHM data, and showcase its versality and potential for application to studying nuclear systems in the Skyrme model.
(KTH Royal Institute of Technology) - Classical and quantum nucleon dynamicsAbstract→I will try to motivate some open problems about classical and quantum nucleon dynamics from holography. This is motivated by recent work describing nuclei as skyrmions generated from instantons.
(Henan University) - Cut-Off KinksAbstract→We answer the question: If a vacuum sector Hamiltonian is regularized by an energy cutoff, how is the one-kink sector Hamiltonian regularized? We find that it is not regularized by an energy cutoff, indeed normal modes of all energies are present in the kink Hamiltonian, but rather the decomposition of the field into normal mode operators yields coefficients which lie on a constrained surface that forces them to become small for energies above the cutoff. This explains the old observation that an energy cutoff of the kink Hamiltonian leads to an incorrect one-loop kink mass. To arrive at our conclusion, we impose that the regularized kink sector Hamiltonian is unitarily equivalent to the regularized vacuum sector Hamiltonian. This condition implies that the two regularized Hamiltonians have the same spectrum and so guarantees that the kink Hamiltonian yields the correct kink mass.
(Beijing Normal University) - Covariant phase space and stability of charged fluid starsAbstract→Covariant phase space formalism plays a complementary role in addressing the quantum dynamics. In this talk, I will demonstrate its application in classical physics by establishing the criterion for both dynamic and thermodynamic stability of charged perfect fluid stars. To this end, I will introduce the Lagrangian description of Einstein-Maxwell-charged fluid system and the concept of canonical energy, etc. I will end my talk with some discussions.
(NAOC, Beijing) - Gravitational Holography and Bell InequalityAbstract→We construct the CHSH (Clauser–Horne–Shimony–Holt) form of Bell inequality, and find that its violation can also be implemented in the holographic model of EPR (Einstein–Podolsky–Rosen) pair. The holographic Schwinger–Keldysh correlators are used to denote the correlators in Bell inequality. [Phys.Lett.B 791 (2019) 73-79]
See the conference photos here
Sven Bjarke Gudnason（比亚科） (河南大学)
马永亮 (Hangzhou Institute for Advanced Study, UCAS)
Markus Amano (Henan University)
Hongbao Zhang (Beijing Normal University)
Baiyang Zhang (Henan University)
Lorenzo Bartolini (Henan University)
Yanan Liu (Henan University)
Meng xue (Henan University)
Ruifeng Zhang (Henan University)
Yun-Long Zhang (NAOC, Beijing)
Stefano Bolognesi (Pisa University)
Josh Cork (Leicester University)
Jingyi Chao (Jiangxi Normal University)
Chris Halcrow (KTH Royal Institute of Technology)
Guilherme Sadovski (Henan University)
Na-Na Ma (Lanzhou University)
stefano bolognesi (pisa)
In total 26 registered participants
External advisory committee