Phonon-induced electron relaxation in weakly-confined single and coupled quantum dots

We investigate charge relaxation rates due to acoustic phonons in weakly-confined quantum dot systems, including both deformation potential and piezoelectric field interactions. Single-electron excited states lifetimes are calculated for single and coupled quantum dot structures, both in homonuclear and heteronuclear devices. Piezoelectric field scattering is shown to be the dominant relaxation mechanism in many experimentally relevant situations. On the other hand, we show that appropriate structure design allows to minimize separately deformation potential and piezolectric field interactions, and may bring electron lifetimes in the range of microseconds.Comment: 20 pages (preprint format), 7 figures, submitted to Physical Review

Topological invariants in interacting Quantum Spin Hall: a Cluster Perturbation Theory approach

Using Cluster Perturbation Theory we calculate Green's functions, quasi-particle energies and topological invariants for interacting electrons on a 2-D honeycomb lattice, with intrinsic spin-orbit coupling and on-site e-e interaction. This allows to define the parameter range (Hubbard U vs spin-orbit coupling) where the 2D system behaves as a trivial insulator or Quantum Spin Hall insulator. This behavior is confirmed by the existence of gapless quasi-particle states in honeycomb ribbons. We have discussed the importance of the cluster symmetry and the effects of the lack of full translation symmetry typical of CPT and of most Quantum Cluster approaches. Comments on the limits of applicability of the method are also provided.Comment: 7 pages, 7 figures: discussion improved, one figure added, references updated. Matches version published in New J. Phy

Entanglement dynamics of electron-electron scattering in low-dimensional semiconductor systems

We perform the quantitative evaluation of the entanglement dynamics in scattering events between two insistinguishable electrons interacting via Coulomb potential in 1D and 2D semiconductor nanostructures. We apply a criterion based on the von Neumann entropy and the Schmidt decomposition of the global state vector suitable for systems of identical particles. From the timedependent numerical solution of the two-particle wavefunction of the scattering carriers we compute their entanglement evolution for different spin configurations: two electrons with the same spin, with different spin, singlet, and triplet spin state. The procedure allows to evaluate the mechanisms that govern entanglement creation and their connection with the characteristic physical parameters and initial conditions of the system. The cases in which the evolution of entanglement is similar to the one obtained for distinguishable particles are discussed.Comment: 22 pages, 7 figures, submitted to Physical Review

On demand entanglement in double quantum dots via coherent carrier scattering

We show how two qubits encoded in the orbital states of two quantum dots can be entangled or disentangled in a controlled way through their interaction with a weak electron current. The transmission/reflection spectrum of each scattered electron, acting as an entanglement mediator between the dots, shows a signature of the dot-dot entangled state. Strikingly, while few scattered carriers produce decoherence of the whole two-dots system, a larger number of electrons injected from one lead with proper energy is able to recover its quantum coherence. Our numerical simulations are based on a real-space solution of the three-particle Schroedinger equation with open boundaries. The computed transmission amplitudes are inserted in the analytical expression of the system density matrix in order to evaluate the entanglement.Comment: 20 pages, 5 figure

Is there a role for dual PI3K/mTOR inhibitors for patients affected with lymphoma?

The activation of the PI3K/AKT/mTOR pathway is a main driver of cell growth, proliferation, survival, and chemoresistance of cancer cells, and, for this reason, represents an attractive target for developing targeted anti-cancer drugs. There are plenty of preclinical data sustaining the anti-tumor activity of dual PI3K/mTOR inhibitors as single agents and in combination in lymphomas. Clinical responses, including complete remissions (especially in follicular lymphoma patients), are also observed in the very few clinical studies performed in patients that are affected by relapsed/refractory lymphomas or chronic lymphocytic leukemia. In this review, we summarize the literature on dual PI3K/mTOR inhibitors focusing on the lymphoma setting, presenting both the three compounds still in clinical development and those with a clinical program stopped or put on hold

Electron interference and entanglement in coupled 1D systems with noise

We estimate the role of noise in the formation of entanglement and in the appearance of single- and two-electron interference in systems of coupled one-dimensional channels semiconductors. Two cases are considered: a single-particle interferometer and a two-particle interferometer exploiting Coulomb interaction. In both of them, environmental noise yields a randomization of the carrier phases. Our results assess how that the complementarity relation linking single-particle behavior to nonlocal quantities, such as entanglement and environment-induced decoherence, acts in electron interferometry. We show that, in a experimental implementation of the setups examined, one- and two-electron detection probability at the output drains can be used to evaluate the decoherence phenomena and the degree of entanglement.Comment: 12 pages, 6 figures. v2: added some references and corrected tex

Grice subtalar arthrodesis of bilateral adult flatfoot in a professional dancer: A case report

Background and aim: Adult acquired flatfoot deformity (AAFD) is a common pathology and an important cause of pain and disability. This deformity causes a progressive flattening of the foot arch which has traditionally been associated with posterior tibialis tendon (PTT) dysfunction. Operative treatment is indicated after the failure of conservative management aiming to achieve proper alignment of the hindfoot and to maintain as much flexibility as possible. If subtalar osteoarthritis is present, subtalar arthrodesis is usually the best therapeutic option. Grice-Green subtalar arthrodesis is a widely used procedure. Methods: This report describes a case of bilateral painful AAFD in a 39-years old female professional dancer treated with Grice-Green subtalar arthrodesis with an autologous corticocancellous graft harvested from the ipsilateral proximal tibia. Surgeries were performed 3 years apart from each other. Results: The patient had good clinical and radiological outcomes. She returned to dance 4 months after surgery with no referred pain or limitations. Conclusions: Due to its versatility and capability to restore the shape and thickness of the hindfoot Grice-Green procedure is a simple and effective technique for the treatment of AAFD with subtalar osteoarthritis and a valid option to solve professional disabilities as it happened in this case with a professional dancer. (www.actabiomedica.it)

Current Best Practices among Cultural Heritage Institutions when Dealing with Copyright Orphan Works and Analysis of Crowdsourcing Options

The purpose of this study is to establish the current state of best practices among Cultural Heritage Institutions (CHIs) when dealing with in-copyright orphan works in three countries: the United Kingdom, Netherlands and Italy. A baseline understanding of current practice provides a benchmark against which crowdsourcing (or any other proposal) to address the challenge posed by orphan works can be evaluated. The research team used a purposive sample to approach the ‘Big 3’ national libraries and film archives in each country, typically including the national library, the national archive and the national film archive. The researchers also aimed to include at least one institution from each jurisdiction that had used the EUIPO database, and one institution that digitized orphan works but opted not to use the database. 15 cultural institutions are included in the study. A semi-structured interview format was used to gather qualitative and quantitative data about the CHIs, their collections, their diligent search processes, the results of rights clearance for specific digitization projects, their thoughts on the potential of crowd-sourcing as a solution, and their views on the current legislative framework