Kondo frustration via charge fluctuations: a route to Mott localisation

We propose a minimal effective impurity model that captures the phenomenology of the Mott-Hubbard metal-insulator transition (MIT) of the half-filled Hubbard model on the Bethe lattice in infinite dimensions as observed by dynamical mean field theory (DMFT). This involves extending the standard Anderson impurity model Hamiltonian to include an explicit Kondo coupling $J$, as well as a local on-site correlation $U_b$ on the conduction bath site connected directly to the impurity. For the case of attractive local bath correlations ($U_{b}<0$), the extended Anderson impurity model (e-SIAM) sheds new light on several aspects of the DMFT phase diagram. For example, the $T=0$ metal-to-insulator quantum phase transition (QPT) is preceded by an excited state quantum phase transition (ESQPT) where the local moment eigenstates are emergent in the low-lying spectrum. Long-ranged fluctuations are observed near both the QPT and ESQPT, suggesting that they are the origin of the quantum critical scaling observed recently at high temperatures in DMFT simulations. The $T=0$ gapless excitations at the QCP display particle-hole interconversion processes, and exhibit power-law behaviour in self-energies and two-particle correlations. These are signatures of non-Fermi liquid behaviour that emerge from the partial breakdown of the Kondo screening.Comment: 49 pages, 17 figures, Supplementary Materials include

Efficacy and Safety of Duckbill Valve Voice Prosthesis in Comparison to Provox

Introduction Voice rehabilitation is the most important issue after total laryngectomy as source of vibration is removed. Three options are there like esophageal voice, electrolarynx and surgical prosthetic voice. Best is the prosthetic speech as voice is generated by lung powered air column. Provox prosthesis is the standard on and most commonly used. But it is costly for the class of patients presenting to our government hospitals. Duckbill prosthesis is very economical and may be helpful for them. There is very limited number of studies with duckbill prosthesis. Materials and Methods Twenty two  post-laryngectomy patients  was selected for this study. Proper counselling was done regarding cost, pros and cons of Provox and Duckbill prosthesis. Fifteen patient selected Duckbill where as seven patient have chosen Provox prosthasis. Voice analysis was done after one month of speech therapy by perceptual voice analysis protocol. Safety and complications arising from prosthesis were also noted. Results There was no significant difference in quality of voice.Both prosthesis are safe if prolong use is avoided. Conclusion There is no significant difference in the quality and safety of both the prosthesis, but huge difference in cost is present. More over it is recurrent cost as it should be changed every year or earlier. One Provox costs around rupees fifty thousand whereas a duckbill prosthesis costs rupees one thousand approximately in Indian market