Insulator-to-metal phase transition in Yb-based Kondo insulators

The periodic Anderson lattice model for the crystalline electric field (CEF)split 4f quartet states is used to describe the Yb-based Kondo insulators/semiconductors. In the slave-boson mean-field approximation, we derive the hybridized quasiparticle bands, and find that decreasing the hybridization difference of the two CEF quartets may induce an insulator-to-metal phase transition. The resulting metallic phase has a hole and an electron Fermi pockets. Such a phase transition may be realized experimentally by applying pressure, reducing the difference in hybridization of the two CEF quartets.Comment: 5 pages, 3 figure

Clinical observation of phacoemulsification in patients with previous trabeculectomy

AIM: To observe the clinical effect of transparent corneal incision phacoemulsification in cataract patients who had undergone different kinds of glaucoma filtration surgeries.<p>METHODS: Totally 43 cases(50 eyes), in which 23 patients with primary angle-closure glaucoma(group A, 26 eyes)and 20 patients with primary open angle glaucoma(group B, 24 eyes), all had undergone glaucoma filtration surgery for more than 6 months. Visual acuity, intraocular pressure, slit lamp, gonioscope, corneal endothelial cell counts, <i>etc</i>., were done before surgery.And transparent corneal incision phacoemulsification combined with artificial lens implantation operation were preformed, postoperative follow-up of 3 to 12 months, visual acuity, intraocular pressure, corneal endothelial cell counts and vision field, <i>etc</i>. were observed and recorded.<p>RESULTS: The visual acuity of 50 eyes(100%)increased with different degree postoperatively, 41 eyes(82%)with postoperative visual acuity ≥0.3; average preoperative intraocular pressure: group A 18.08±5.08mmHg(1mmHg=0.133kpa), group B 14.48±3.52mmHg; Postoperative follow-up average intraocular pressure: group A 13.65±3.51mmHg, group B 14.28±3.41 mmHg, intraocular pressure changed significantly pre and post-operation in group A(<i>P</i><0.05), there was no significant difference between pre and post-operation in group B(<i>P</i>>0.05); Postoperative intraocular pressure of 1 eye in group A and 3 eyes in group B rose within three days post-operation, the intraocular pressure fluctuated between 21-33mmHg, with drug therapy and drug withdral when intraocular pressure epistrophy; Intraocular pressure was stable in the follow-up process.Corneal endothelial cell density: pre-operation group A was 2 293.57±352.24(cells/mm²), group B 2 658.14±458.69(cells/mm²), post- operation group A 2 175.95±379.16(cells/mm²), group B 2 442.97±477.30(cells/mm²), cell loss rate: 5.13% in group A, and 8.10% in group B. Postoperative visual acuity was related to vision field damage in patients, the more visual field damage, the longer the duration. <p>CONCLUSION: Visual function restore is stable in transparent corneal incision phacoemulsification in cataract patients who underwent glaucoma filtration surgeries; the intraocular pressure can be controlled effectively, and can further reduce the intraocular pressure of angle-closure glaucoma. Preoperative comprehensive evaluation of the affected eye and appropriate technique selection are benefit to the improvement of operation effect and the reduction of complications

Search for C=+C=+ charmonium and XYZ states in e+e−→γ+He^+e^-\to \gamma+ H at BESIII

Within the framework of nonrelativistic quantum chromodynamics, we study the production of $C=+$ charmonium states $H$ in $e^+e^-\to \gamma~+~H$ at BESIII with $H=\eta_c(nS)$ (n=1, 2, 3, and 4), $\chi_{cJ}(nP)$ (n=1, 2, and 3), and $^1D_2(nD)$ (n=1 and 2). The radiative and relativistic corrections are calculated to next-to-leading order for $S$ and $P$ wave states. We then argue that the search for $C=+$ $XYZ$ states such as $X(3872)$, $X(3940)$, $X(4160)$, and $X(4350)$ in $e^+e^-\to \gamma~+~H$ at BESIII may help clarify the nature of these states. BESIII can search $XYZ$ states through two body process $e^+e^-\to \gamma H$, where $H$ decay to $J/\psi \pi^+\pi^-$, $J/\psi \phi$, or $D \bar D$. This result may be useful in identifying the nature of $C=+$ $XYZ$ states. For completeness, the production of $C=+$ charmonium in $e^+e^-\to \gamma +~H$ at B factories is also discussed.Comment: Comments and suggestions are welcome. References are update