The dependence of the QCD coupling constant with a strong magnetic field and the implications for the critical temperature of the chiral phase transition are investigated. It is found that the coupling constant becomes anisotropic in a strong magnetic field and that the quarks, confined by the field to the lowest Landau level where they pair with antiquarks, produce an antiscreening effect. These results lead to inverse magnetic catalysis, providing a natural explanation for the behavior of the critical temperature in the strong-field region.

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Thermodynamic formulas for investigating systems with density and/or temperature dependent particle masses are generally derived from the fundamental derivation equality of thermodynamics. Various problems in the previous treatments are discussed and modified. Properties of strange quark matter in bulk and strangelets at both zero and finite temperature are then calculated based on the new thermodynamic formulas with a new quark mass scaling, which indicates that low mass strangelets near β equilibrium are multi-quark states with an anti-strange quark, such as the pentaquark (u 2 d 2s ) for baryon nmber 1 and the octaquark (u 4 d 3s ) for dibaryon etc.

We propose a modification of the finite size effects due to the effective bag function in the extended quark quasiparticle model with a running coupling constant. The bag function is associated with the quark chemical potential and the radius of strangelets. Considering the medium effects, the surface tension should be redefined with an additional term described by the surface term of the bag function. With the increasing baryon number of stable strangelets, it is found that the coupling strength becomes stronger while the surface tension decreases in the vicinity of 35 MeV fm −2 for strangelets of the baryon number greater than 10 3 . The comparison with the bag model is shown and the distinction for smaller strangelets is very clear.

The quark quasiparticle model is extended to study the properties of color-flavor locked strange quark matter at finite chemical potential and in a strong magnetic field. We present a self-consistent thermodynamic treatment by employing a chemical potential dependent bag function. It is found that the magnetized color-flavor-locked (MCFL) matter is more stable than other phases within a proper magnitude of magnetic field. The stability window is graphically shown for the MCFL matter compared with ordinate magnetized matter. The anisotropic structure of MCFL matter is dominated by the magnetic field and almost independent of the energy gaps. A critical maximum magnetic field of about $1.56\times 10^{18}$ G is found, under which MCFL matter is absolutely stable with respect to nuclear matter.Comment: 10 pages, 5 figure

The quasiparticle model is extended to investigate the properties of strange quark matter in a strong magnetic field at finite densities. For the density-dependent quark mass, self-consistent thermodynamic treatment is obtained with an additional effective bag parameter, which depends not only on the density but also on the magnetic field strength. The magnetic field makes strange quark matter more stable energetically when the magnetic field strength is less than a critical value of the order 10 7 Gauss depending on the QCD scale Λ. Instead of being a monotonic function of the density for the QCD scale parameter Λ > 126 MeV, the effective bag function has a maximum near 0.3 ∼ 0.4 fm −3 . The influence of the magnetic field and the QCD scale parameter on the stiffness of the equation of state of the magnetized strange quark matter and the possible maximum mass of strange stars are discussed.

We report the synthesis and excellent two‐photon‐sensitized luminescence properties of a new complex [Eu(tta)3dmbpt] (tta = henoyltrifluoroacetonate; dmbpt = 2‐(N,N‐diethyl‐2,6‐dimethylanilin‐4‐yl)‐4,6‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,3,5‐triazine) that exhibits the highest efficiency of lanthanide luminescence when excited by near‐infrared (NIR) laser pulses (action cross section of two‐photon‐excited fluorescence δ × ΦF: 85 GM at 812 nm and 56 GM at 842 nm; 1 GM = 10–50 cm4 s photon–1 molecule–1). Compared to a previously reported [Eu(tta)3dpbt] complex, (dpbt = 2‐(N,N‐diethylanilin‐4‐yl)‐4,6‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,3,5‐triazine), [Eu(tta)3dmbpt] has two excess methyl groups at the 2,6‐positions of the phenyl ring. Crystallographic data of dmbpt show that the 2,6‐dimethyl substitutes bring about a significant twist in the conformation of the diethylamino group compared to that in dpbt, which severely influences the conjugation in the ground state between the electron lone pair of N in the –N(CH2–)2 moiety and the aromatic electron system in dmbpt. The large two‐photon absorption (TPA) cross section of dmbpt is mainly derived from its large static dipole moment difference between the S0 and the S1 states, which is partly responsible for the high capability of two‐photon‐sensitized luminescence of [Eu(tta)3dmbpt]. The broader two‐ and single‐photon excitation windows and the superior two‐photon‐sensitized luminescent properties in the long‐wavelength NIR region of [Eu(tta)3dmbpt] compared to [Eu(tta)3dpbt] are also explained according to the calculated results and twisted structure.

We report an alternative approach, that is, forming Eu(tta)3dpbt (dpbt = 2-( N, N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine, tta = thenoyltrifluoroacetonato) nanoparticles in water/methanol mixtures, to satisfy the combined requirements of good dispersibility in water solutions and efficient long-wavelength sensitization for Eu (III) complexes to be used in biological applications. The size of Eu(tta)3dpbt colloidal particles with very high luminescent capabilities can be modulated to some extent by changing the preparation conditions. The optical excitation window for the Eu (III) luminescence of Eu(tta)3dpbt nanoparticles, extending up to 475 nm, is wider than that of Eu(tta)3dpbt molecules dissolved in toluene. This is the first example for obviously extending the sensitization window of luminescent lanthanide materials to the long-wavelength region by forming nanoparticles of a lanthanide complex. Quantum yields of Eu (III) luminescence of the prepared Eu(tta)3dpbt colloidal particles, with an average diameter of 33.1 nm, are 0.27, 0.27, 0.24, 0.19, 0.14, and 0.01 upon excitation at 402, 420, 430, 440, 450, and 475 nm, respectively. The Eu(tta)3dpbt nanoparticles exhibited excellent two-photon sensitization performance with a highest delta Phi value of 3.2 x 10(5) GM (1 GM = 10(-50) cm4 s photo(-1) particle(-1)) at the excitation wavelength of 832 nm, which is about 7 times higher than the highest value reported for the CdSe/ZnS core-shell quantum dots. The favorable luminescent properties and the good dispersibility in water solutions of the Eu(tta)3dpbt nanoparticles are very promising for the development of new luminescent nanoprobes for bioanalysis.