Overview of QCS 2017
Central density of dense and compact objects like neutron stars attains to several times the density of atomic nuclei. In such high densities, various phases of hadronic matter and/or quark matter may be realized.It is one of the fundamental issues in nuclear physics and astrophysics to obtain the equation of state (EOS) of matter at high densities and/or high temperatures including phase transitions and phase equilibrium between various phases and to understand the phase diagram on the basis of underlying properties of Quantum Chromodynamics (QCD), i.e., asymptotic freedom, confinement of quarks, and chiral symmetry.

In recent years, we have faced with novel developments of dense matter physics from both theoretical and observational viewpoints: Effects of magnetic fields have been taken into account in addition to temperature and density to theoretically obtain the EOS of dense matter and QCD phase diagram. Very recent observations of gravitational waves (GW) from merger of binary black holes opened gravitational-wave astronomy. Future detection of GW from neutron star mergers will provide us with important information on the EOS of dense matter. Also observations of massive neutron stars as large as two times the solar mass have imposed stringent constraints on the stiffness of the EOS.

The purpose of the workshop is to discuss present researches on various phases and EOS of dense matter and the QCD phase diagram in terms of hadron and quark degrees of freedom. We promote interdisciplinary cooperative works from various points of view in the fields of elementary particle and nuclear physics, astrophysics, and condensed matter physics, discussing consistency of theoretical results with observational and experimental information, and aim to share with each other the present reaching points and future directions of research. We also expand our scope to the hadron nuclear physics, particularly pursued at J-PARC, which are closely related to neutron-rich nuclei and nuclear matter, and dense strange matter in the neutron stars.

The first workshop of this series has been held as a bilateral meeting of China and Japan in Beijing, China in 2014. This time, the second one is going to be held as a trilateral meeting of Japan, China, and Korea. We expect that the workshop will not only contribute to further progress of research in each country but also promote international cooperation in Asia as a starting point for young researchers and newcomers in this field.

In the workshop, the following topics are to be covered:
(1) QCD phase diagram
- nonuniform chiral phase transition, color superconductivity, properties of QCD matter under strong magnetic fields, etc.

(2) Various phases of dense matter in terms of hadron and quark degrees of freedom
- crossover between hadron and quark phases, mixed phases ("pasta" phases) associated with quark-hadron phase transition, etc.

(3) Other topics related with dense matter
- EOS for hadron phases (kaon condensation, hyperon-mixing and three-body repulsive effects between baryons at high densities)
- dense matter and weak interaction (cooling mechanisms of neutron stars and cooling scenario consistent with observations), etc.

(4) Possible derivation of the EOS for dense matter through detection of gravitational waves from neutron-star mergers

(5) Origin, structure, and evolution of strong magnetic fields in magnetars, properties and EOS of dense matter in strong magnetic fields
- anti-glitch, quasi-periodic X-ray emission and relevance to baryon superfluidity, etc.

(6) Other topics related with physics of compact stars
- supernova explosion and EOS for hot and dense matter, neutrino transportation in supernova matter, relevant physics of heavy-ion collisions, etc.

We are planning to invite the following speakers for review talks on the above topics:

  1. Name (Affiliation); Title (tentative)
  2. T. Enoto (Kyoto U.); X- ray observation of neutron stars
  3. Y. Kim (Inst for Basic Sci.); Role of symmetry energy and dense matter physics with rare isotopes
  4. C.-H Lee (Pusan National U.); Strangeness in neutron star cooling
  5. A. Ohnishi (YITP); High-density matter and strangeness physics (Implications for QGP and heavy-ion collisions)
  6. Y. Sekiguchi(Toho U.); Gravitational wave astronomy:from numerical relativity
  7. H. Shen (Nankai U.); Equation of state for supernovae and neutron stars
  8. Y. Suwa (YITP); Supernova matter and neutrino transportation in supernovae
  9. T. Takatsuka (Iwate U.); Phase transition, phase equilibrium between hadron - quark phases and EOS
  10. T. Tatsumi (Kyoto U.); Inhomogeneous chiral phase in dense quark matter
  11. S. Tsuruta (Montana U.); Current topics about cooling of neutron stars
  12. P. Zhuang (Tsinhua U.); Quark matter in an external magnetic field

T. Tatsumi (Kyoto Univ.) (chair), T. Maruyama (JAEA), R. Xu (Peking Univ.), C.-H. Lee (Pusan Nat. Univ.), H. Sotani (NAOJ), T. Muto (Chiba Inst. Tech.), N. Yasutake (Chiba Inst. Tech.), G. Peng (Univ. Chinese Academy of Sci.), C.H. Hyun (Daegu Univ.), K. Kwak (Ulsan Nat. Inst. Of Sci. and Tech.)

Local organizing committee
T. Tatsumi (Kyoto Univ.) , T. Maruyama (JAEA) , H. Sotani (NAOJ), T. Muto (Chiba Inst. Tech.), N. Yasutake (Chiba Inst. Tech.), K. Nakazato (Kyushu Univ.), T.-G. Lee (Kochi Univ.)

Contact person
T. Maruyama, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan Tel: +81 29 282 5457