Spin correlations in the electron-doped high-transition-temperature superconductor Nd{2-x}Ce{x}CuO{4+/-delta}

High-transition-temperature (high-Tc) superconductivity develops near antiferromagnetic phases, and it is possible that magnetic excitations contribute to the superconducting pairing mechanism. To assess the role of antiferromagnetism, it is essential to understand the doping and temperature dependence of the two-dimensional antiferromagnetic spin correlations. The phase diagram is asymmetric with respect to electron and hole doping, and for the comparatively less-studied electron-doped materials, the antiferromagnetic phase extends much further with doping [1, 2] and appears to overlap with the superconducting phase. The archetypical electron-doped compound Nd{2-x}Ce{x}CuO{4\pm\delta} (NCCO) shows bulk superconductivity above x \approx 0.13 [3, 4], while evidence for antiferromagnetic order has been found up to x \approx 0.17 [2, 5, 6]. Here we report inelastic magnetic neutron-scattering measurements that point to the distinct possibility that genuine long-range antiferromagnetism and superconductivity do not coexist. The data reveal a magnetic quantum critical point where superconductivity first appears, consistent with an exotic quantum phase transition between the two phases [7]. We also demonstrate that the pseudogap phenomenon in the electron-doped materials, which is associated with pronounced charge anomalies [8-11], arises from a build-up of spin correlations, in agreement with recent theoretical proposals [12, 13].Comment: 5 pages, 4 figure

Fine structure of alpha decay in odd nuclei

Using an alpha decay level scheme, an explanation for the fine structure in odd nuclei is evidenced by taking into account the radial and rotational couplings between the unpaired nucleon and the core of the decaying system. It is stated that the experimental behavior of the alpha decay fine structure phenomenon is directed by the dynamical characteristics of the system.Comment: 8 pages, 3 figures, REVTex, submitted to Physical Review

A Complexity View of Rainfall

We show that rain events are analogous to a variety of nonequilibrium relaxation processes in Nature such as earthquakes and avalanches. Analysis of high-resolution rain data reveals that power laws describe the number of rain events versus size and number of droughts versus duration. In addition, the accumulated water column displays scale-less fluctuations. These statistical properties are the fingerprints of a self-organized critical process and may serve as a benchmark for models of precipitation and atmospheric processes.Comment: 4 pages, 5 figure

Morpho-anatomical and microbiological analysis of kiwifruit roots with KVDS symptoms

Italy, one of the largest producers of kiwifruit in the world, has lost 10% of its production in recent years because of the spread of the kiwifruit vine decline syndrome (KVDS). Although the aetiology of KVDS has not been characterized, root rot symptoms are often associated with water stagnation and root asphyxia. To investigate causal factors and potential solutions to counter this syndrome, an experimental trial was undertaken in a kiwifruit orchard affected by KVDS in Latina (central Italy) in 2020. Root samples from healthy plants were collected and compared with samples taken from plants affected by KVDS. Macroscopically, the roots affected by KVDS were rotting, showing a loss of rhizodermis and cortical parenchyma. Microscopic analysis revealed damage to the root system with tissue breakdown and decomposition, flaking of the rhizodermis, cortical area with a clear loss of cell turgor, initial decay of the stele and evident detachment of the cortex from the central conducting tissues. Light microscopy, morphological and molecular analyses were carried out on the rhizodermis of roots showing decay and death symptoms. Total DNA extracted from the pure fungal colonies was amplified by PCR with ITS primers, amplicons directly sequenced, and the obtained nucleotide sequences were compared with those present in the GenBank database (NCBI) through BLAST analysis. Genomic analysis allowed the identification of three abundant fungi namely Ilyonectria vredenhoekensis, Fusarium oxysporum and Paraphaeosphaeria michotii. Further investigation is required to determine the role of these fungi in KVDS, whether they are species favoured by water stagnation and root asphyxia; their abundance and presence in other regions, orchards, and kiwifruit species; if they compromise roots functionality individually or conjunction with other microbial pathogens or abiotic factors; and if they contribute to plant death associated with KVDS

Evidence for a Soft Nuclear Equation-of-State from Kaon Production in Heavy Ion Collisions

The production of pions and kaons has been measured in Au+Au collisions at beam energies from 0.6 to 1.5 AGeV with the Kaon Spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.Comment: 14 pages, 2 figures, accepted for publication in Phys. Rev. Let

Production of Charged Pions, Kaons and Antikaons in Relativistic C+C and C+Au Collisions

Production cross sections of charged pions, kaons and antikaons have been measured in C+C and C+Au collisions at beam energies of 1.0 and 1.8 AGeV for different polar emission angles. The kaon and antikaon energy spectra can be described by Boltzmann distributions whereas the pion spectra exhibit an additional enhancement at low energies. The pion multiplicity per participating nucleon M(pi+)/A_part is a factor of about 3 smaller in C+Au than in C+C collisions at 1.0 AGeV whereas it differs only little for the C and the Au target at a beam energy of 1.8 AGeV. The K+ multiplicities per participating nucleon M(K+)/A_part are independent of the target size at 1 AGeV and at 1.8 AGeV. The K- multiplicity per participating nucleon M(K-)/A_part is reduced by a factor of about 2 in C+Au as compared to C+C collisions at 1.8 AGeV. This effect might be caused by the absorption of antikaons in the heavy target nucleus. Transport model calculations underestimate the K-/K+ ratio for C+C collisions at 1.8 AGeV by a factor of about 4 if in-medium modifications of K mesons are neglected.Comment: 19 pages, 14 figures, accepted for publication in Eur. Phys. J.

Strength of Correlations in electron and hole doped cuprates

High temperature superconductivity was achieved by introducing holes in a parent compound consisting of copper oxide layers separated by spacer layers. It is possible to dope some of the parent compounds with electrons, and their physical properties are bearing some similarities but also significant differences from the hole doped counterparts. Here, we use a recently developed first principles method, to study the electron doped cuprates and elucidate the deep physical reasons why their behavior is so different than the hole doped materials. We find that electron doped compounds are Slater insulators, e.g. a material where the insulating behavior is the result of the presence of magnetic long range order. This is in sharp contrast with the hole doped materials, where the parent compound is a Mott charge transfer insulator, namely a material which is insulating due to the strong electronic correlations but not due to the magnetic order.Comment: submitted to Nature Physic

An interferometric complementarity experiment in a bulk Nuclear Magnetic Resonance ensemble

We have experimentally demonstrated the interferometric complementarity, which relates the distinguishability $D$ quantifying the amount of which-way (WW) information to the fringe visibility $V$ characterizing the wave feature of a quantum entity, in a bulk ensemble by Nuclear Magnetic Resonance (NMR) techniques. We primarily concern on the intermediate cases: partial fringe visibility and incomplete WW information. We propose a quantitative measure of $D$ by an alternative geometric strategy and investigate the relation between $D$ and entanglement. By measuring $D$ and $V$ independently, it turns out that the duality relation $D^{2}+V^{2}=1$ holds for pure quantum states of the markers.Comment: 13 page, 5 PS figure