Quarkyonic Matter and Chiral Spirals

The nuclear matter, deconfined quark matter, and Quarkyonic matter in low temperature region are classified based on the 1/Nc expansion. The chiral symmetry in the Quarkyonic matter is investigated by taking into account condensations of chiral particle-hole pairs. It is argued that the chiral symmetry and parity are locally violated by the formation of chiral spirals, < psibar exp(2 i mu z gamma^0 gamma^z) psi >. An extension to multiple chiral spirals is also briefly discussed.Comment: Prepared for Hot Quark 2010, 4 page

Delineating the properties of matter in cold, dense QCD

The properties of dense QCD matter are delineated through the construction of equations of state which should be consistent with QCD calculations in the low and high density limits, nuclear laboratory experiments, and the neutron star observations. These constraints, together with the causality condition of the sound velocity, are used to develop the picture of hadron-quark continuity in which hadronic matter continuously transforms into quark matter (modulo small 1st order phase transitions). For hadronic matter (at baryon density nB > ~2n0 with n0 ~ 0.16 fm^(-3) being the nuclear saturation density) we use equations of state by Togashi et al. based on microscopic variational many-body calculations, and for quark matter (nB > ~5n0) we construct equations of state using a schematic quark model (with strangeness) whose interactions are motivated by the hadron phenomenology. The region between hadronic and quark matters (~2n0 < nB < ~5n0), which is most difficult to calculate, is treated by highly constrained interpolation between nuclear and quark matter equations of state. The resultant unified equation of state at zero temperature and beta-equilibrium, which we call Quark-Hadron-Crossover (QHC18 and QHC19), is consistent with the measured properties of neutron stars and in addition gives us microscopic insights into the properties of dense QCD matter. In particular to ~10n0 the gluons can remain as non-perturbative as in vacuum and the strangeness can be as abundant as up- and down-quarks at the core of two-solar mass neutron stars. Within our modeling the maximum mass is found less than ~2.35 times solar mass and the baryon density at the core ranges in ~5-8n0.Comment: 18 pages 11 figures, AIP Proceedings of the Xiamen-CUSTIPEN Workshop on the EOS of Dense Neutron-Rich Matter in the Era of Gravitational Wave Astronomy, Jan. 3-7, Xiamen, China; v2 references are adde

The quark mass gap in strong magnetic fields

Quarks in strong magnetic fields (|eB|>>Lambda_QCD^2 ~ 0.04 GeV^2) acquire enhanced infrared phase space proportional to |eB|. Accordingly they provide larger chiral condensates and stronger backreactions to the gluon dynamics. Confronting theories with lattice data at various values of |eB|, one can test theoretical ideas as well as validity of various approximations, domain of applicability of the effective models, and so on. The particularly interesting findings on the lattice are inverse magnetic catalysis and linear growth of the chiral condensate as a function of |eB|, which pose theoretical challenges. In this talk we propose a scenario to explain both phenomena, claiming that the quark mass gap should stay at around ~ Lambda_QCD, instead of ~|eB|^{1/2} which has been supposed from dimensional arguments and/or effective model calculations. The contrast between infrared and ultraviolet behaviors of the interaction is a key ingredient to obtain the mass gap of ~Lambda_QCD.Comment: 4 pages, proceedings of the XXIV Quark Matter conference, May 19-24 2014, Darmstadt (Germany

Diamonds are not forever : Botswana medium-term fiscal sustainability

This paper analyzes Botswana's medium-term fiscal sustainability in view of the expected depletion of diamonds in the future. The analysis shows that in the absence of policy adjustments, Botswana's current fiscal policy strategy is unsustainable over the longer term, which could endanger macroeconomic stability and Botswana's reputation as Africa's success story. Ensuring medium-term sustainability of Botswana's public finances requires stronger revenue collection, through improved revenue administration, greater tax enforcement, and the rationalization of tax exemptions in order to realize the full revenue potential. Opportunities also exist to generate more revenue from the non-mining sector through changes in the tax regime. At the same time, the government needs to maximize the effectiveness of public expenditure and bring down public spending to levels that are more in line with long-term revenue prospects. A greater control over the public sector wage bill is critically important. In-house capacity for macroeconomic monitoring and fiscal analysis also needs to be enhanced further. Looking ahead, growth of a dynamic non-mining sector is crucial for Botswana not only from the fiscal sustainability point of view, but from the point of view of achieving balanced development that will create jobs and deliver durable reduction in poverty and inequality. Fiscal policy will have to play a central role in this process.Debt Markets,Economic Theory&Research,Public Sector Expenditure Policy,Access to Finance,Public Sector Economics

QCD Sum Rules and 1/NcN_c expansion

The 1/$N_c$ arguments are developed to classify the hadronic states in the correlators. Arguments applied to the $\sigma$ meson correlator enable to separate the instanton, glueball, and, in particular, the $\pi\pi$ scattering states by $1/N_c$ from both 2q and 4q correlators. The bare resonance pole with no mixing effects are analyzed with the QCD sum rules (QSR). The results suggest the existence of nontrivial correlation for the mass reduction of 4q system.Comment: Presented at at YITP International Symposium Fundamental Problems in Hot and / or Dense QCD, Kyoto, Japan, 3-6 Mar 200

Phenomenological QCD equations of state for neutron star mergers

Thermal QCD equations of state at high baryon density are sensitive to the phase structure and the resulting excitation modes. The leading contribution at low temperature can be either ~p_F^2 T^2 (pF: Fermi momentum, T: temperature) for phases with gapless quarks, or ~T^4 for phases with gapped quarks. In the latter the thermal pressure is dominated by collective modes. Starting with a schematic quark model developed for neutron star structure, we estimate the thermal contributions and zero point energy from the Nambu-Goldstone modes by building them upon the mean field background for the color-flavor-locked quark matter. Applying the phase shift representation for thermodynamic potentials, we include not only the bound state pairs but also resonating pairs. According to the Levinson's theorem, the high energy contributions tend to cancel the pole contributions to the thermodynamics, tempering the UV behaviors in the zero point energy. Our primary target in this talk is the domain with baryon density nB as large as ~ 5-10n_0 (n_0 = 0.16 fm^{-3}: nuclear saturation density), and the temperature T of the order ~30-100 MeV. The insights into this domain may be obtained through the future detection of gravitational waves from neutron star merging events.Comment: 5 pages, 2 figures; prepared for quark matter 2017, Chicago, Illinois, US