Nucleon excited states on the lattice

We study the pion-nucleon system in s-wave in the framework of lattice QCD in order to gain new information on the nucleon excited states. We perform simulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266 MeV. The results show that including the two-particle states drastically changes the energy levels. The variational analysis and the distillation approach play an important role in the extraction of the energy levels. The phase shift analysis allows to extract information on the resonance nature of the observed states.Comment: 6 pages, 2 figures, talk presented at Excited QCD 2013, Bjelasnica Mountain, Sarajev

EDUCATION Elementary and Secondary Education: Authorize the Reading or Posting of Certain Writings, Documents, and Records Without Content-Based Censorship Thereof; Provide for Notice to Local School Superintendents; and for Other Purposes

The bill would have permitted state school boards to allow and encourage their teachers and administrators to read or post in their school building, classrooms, or at any event, documents or any portion of documents that relate to American heritage. The bill would have provided a list of documents, including the Constitution, the Declaration of Independence, the Mayflower Compact, and United States Supreme Court decisions. The bill would have prohibited content-based censorship of American history and heritage-based documents regarding any religious references

EDUCATION Elementary and Secondary Education: Authorize the Reading or Posting of Certain Writings, Documents, and Records Without Content-Based Censorship Thereof; Provide for Notice to Local School Superintendents; and for Other Purposes

The bill would have permitted state school boards to allow and encourage their teachers and administrators to read or post in their school building, classrooms, or at any event, documents or any portion of documents that relate to American heritage. The bill would have provided a list of documents, including the Constitution, the Declaration of Independence, the Mayflower Compact, and United States Supreme Court decisions. The bill would have prohibited content-based censorship of American history and heritage-based documents regarding any religious references

Equazioni di stato della materia in astrofisica

L'obiettivo del presente elaborato è quello di illustrare le equazioni di stato della materia, in particolare inserendole in un contesto astrofisico. Dopo una breve introduzione di carattere storico-scientifico, si procede con la presentazione delle principali funzioni ed equazioni di stato della meccanica statistica. In seguito, si enunciano le maggiori differenze fra sistemi degeneri e non degeneri e le rispettive statistiche da cui sono governati. Nella successiva sezione, si prosegue addentrandosi nell'ambito più specificatamente astrofisico in cui la trattazione si inserisce, con preciso riferimento al mondo delle stelle, interpretabili come sistemi in cui la materia si comporta come un gas perfetto o degenere. Per concludere, vengono riportati alcuni esempi di applicazione delle formule presentate nei paragrafi precedenti, facendo riferimento anche a semplici esercizi, con l'intento di giungere ad importanti conclusioni astrofisiche

Interface engineering for perovskite solar cells based on 2d‐materials: A physics point of view

The last decade has witnessed the advance of metal halide perovskites as a promising low-cost and efficient class of light harvesters used in solar cells (SCs). Remarkably, the efficiency of lab-scale perovskite solar cells (PSCs) reached a power conversion efficiency of 25.5% in just similar to 10 years of research, rivalling the current record of 26.1% for Si-based PVs. To further boost the performances of PSCs, the use of 2D materials (such as graphene, transition metal dichalcogenides and transition metal carbides, nitrides and carbonitrides) has been proposed, thanks to their remarkable optoelectronic properties (that can be tuned with proper chemical composition engineering) and chemical stability. In particular, 2D materials have been demonstrated as promising candidates for (i) accelerating hot carrier transfer across the interfaces between the perovskite and the charge extraction layers; (ii) improving the crystallization of the perovskite layers (when used as additives in the precursor solution); (iii) favoring electronic bands alignment through tuning of the work function. In this mini-review, we discuss the physical mechanisms underlying the increased efficiency of 2D material-based PSCs, focusing on the three aforementioned effects