1,721,129 research outputs found
RELIABILITY OF THE SKELETOCHRONOLOGICAL METHOD IN CARETTA CARETTA FROM THE ADRIATIC SEA.
No full textMicrowave photon detectors based on semiconducting double quantum dots
Full text linkDetectors of microwave photons find applications in different fields ranging from security to cosmology. Due to the intrinsic difficulties related to the detection of vanishingly small energy quanta ̄hω, significant portions of the microwave electromagnetic spectrum are still uncovered by suitable techniques. No prevailing technology has clearly emerged yet, although different solutions have been tested in different contexts. Here, we focus on semiconductor quantum dots, which feature wide tunability by external gate voltages and scalability for large architectures. We discuss possible pathways for the development of microwave photon detectors based on photon-assisted tunneling in semiconducting double quantum dot circuits. In particular, we consider implementations based on either broadband transmission lines or resonant cavities, and we discuss how developments in charge sensing techniques and hybrid architectures may be beneficial for the development of efficient photon detectors in the microwave range
A density-functional study of heterometallic Cr-based molecular rings
No full textWe present a density-functional theoretical investigation of the electronic and magnetic properties of octametallic Cr-based molecular antiferromagnetic rings. The presence of the divalent magnetic ion M unbalances the charge and the spin of the parent Cr8 ring, leading to a finite total spin in the molecules. Results are presented for Cr8, i.e., [Cr8F 8(O2CH)16] (1), and for Cr7M rings belonging to two different derivatives, i.e., [Me2NH 2][Cr7MF8(O2CH)16], with M = Ni, Mn, Fe, and Cu, and Me=CH3 (2, "green" derivative), and [Cr7 NiF3(C6H10NO 5)(O2CH)15 (H2O)] (3, "purple" derivative). Exchange interaction parameters have been extracted from broken-symmetry calculations and compared with the available experiments; in agreement with them, we find that exchange parameters are rather similar in the two derivatives, although somewhat larger in the "purple" derivative. The analysis of the electronic properties shows some differences depending on M, in particular in the size of the highest occupied molecular orbital to lowest unoccupied molecular orbital (HOMO-LUMO) gaps. For all the "green" rings we observe that the HOMOs are localized on the divalent ion site, while the HOMOs for the "purple" Cr7Ni have a more delocalized nature; LUMOs, instead, are, except for "green" Cr7Cu, localized on the Cr atoms opposite to the M site. We discuss how these findings may show up in terms of an asymmetric I-V curve in molecular junctions working in the sequential tunneling regime, or help in discerning the orientation of the molecules with respect to a surface, in scanning tunneling experiments. © 2010 American Chemical Society
ANALISI SCHELETROCRONOLOGICA SU ESEMPLARI DI CARETTA CARETTA (REPTILIA, CHELONIA) CAMPIONATI NEL MARE ADRIATICO
No full text
Quantum sensing of magnetic fields with molecular spins
Full text linkSpins are prototypical systems with the potential to probe magnetic fields down to the atomic scale limit. Exploiting their quantum nature through appropriate sensing protocols allows to enlarge their applicability to fields not always accessible by classical sensors. Here we first show that quantum sensing protocols for AC magnetic fields can be implemented with molecular spin ensembles embedded into hybrid quantum circuits. We then show that, using only echo detection at microwave frequency and no optical readout, Dynamical Decoupling protocols synchronized with the AC magnetic fields can enhance sensitivity up to S ≈ 10^(−10) − 10^(−9) T Hz^(−1/2) with a low (4-5) number of applied pulses. These results paves the way for the development of strategies to exploit molecular spins as quantum sensors
Uncollapsed LaFe2 As2 phase: Compensated, highly doped, electron-phonon-coupled, iron-based superconductor
No full textThe recently discovered LaFe2As2 superconducting compound, member of the 122 family of iron pnictide superconductors, becomes superconducting below TcGëê13K, yet its nominal doping apparently places it in the extreme overdoped limit, where superconductivity should be suppressed. In this work, we investigate the normal state of magneto- and thermoelectric transport and specific heat of this compound. The experimental data are consistent with the presence of highly compensated electron and hole bands, with Gê+0.42 electrons per unit cell just above Tc, and high effective masses Gê+3m0. The temperature dependence of transport properties strongly resembles that of conventional superconductors, pointing to a key role of electron-phonon coupling. From this evidence, LaFe2As2 can be regarded as the connecting compound between unconventional and conventional superconductors
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
