1,805 research outputs found
Anomalous Josephson effect in semiconducting nanowires as a signature of the topologically nontrivial phase
We study Josephson junctions made of semiconducting nanowires with Rashba
spin-orbit coupling, where superconducting correlations are induced by the
proximity effect. In the presence of a suitably directed magnetic field, the
system displays the anomalous Josephson effect: a nonzero supercurrent in the
absence of a phase bias between two superconductors. We show that this
anomalous current can be increased significantly by tuning the nanowire into
the helical regime. In particular, in a short junction, a large anomalous
current is a signature for topologically nontrivial superconductivity in the
nanowire.Comment: 10 pages, 9 figures; published versio
3,5-Bis(4-chlorobenzylidene)-1-methylpiperidin-4-one
In the title molecule, C20H17Cl2NO, the central heterocyclic ring adopts a flattened boat conformation. The dihedral angles between the planar part of this central heterocyclic ring [maximum deviation = 0.004 (1) Å] and the two almost planar side-chain fragments [maximum deviations = 0.015 (1) and 0.019 (1) Å], that include the aromatic ring and bridging atoms, are 18.1 (1) and 18.0 (1)°. In the crystal, pairs of weak intermolecular C—H⋯O hydrogen bonds link molecules into inversion dimers that form stacks along the a axis. The structure is further stabilized by weak intermolecular C—H⋯π interactions involving the benzene rings
1-Benzyl-3,5-bis(4-chlorobenzylidene)piperidin-4-one
The title compound, C26H21Cl2NO, crystallizes with two symmetry-independent molecules (A and B) in the asymmetric unit. In both molecules, the central heterocyclic ring adopts a sofa conformation. The dihedral angles between the planar part of this central heterocyclic ring [maximum deviations of 0.011 (1) and 0.036 (1) Å in molecules A and B, respectively] and the two almost planar [maximum deviations of 0.020 (1) and 0.008 (1) Å in A and 0.007 (1) and 0.011 (1) in B] side-chain fragments that include the aromatic ring and bridging atoms are 20.1 (1) and 31.2 (1)° in molecule A, and 26.4 (1) and 19.6 (1)° in molecule B. The dihedral angles between the planar part of the heterocyclic ring and the benzyl substituent are 79.7 (1) and 53.2 (1)° in molecules A and B, respectively. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link the two independent molecules into dimers
The coexistence of superconductivity and ferromagnetism in nano-scale metallic grains
A nano-scale metallic grain in which the single-particle dynamics are chaotic
is described by the so-called universal Hamiltonian. This Hamiltonian includes
a superconducting pairing term and a ferromagnetic exchange term that compete
with each other: pairing correlations favor minimal ground-state spin, while
the exchange interaction favors maximal spin polarization. Of particular
interest is the fluctuation-dominated regime where the bulk pairing gap is
comparable to or smaller than the single-particle mean level spacing and the
Bardeen-Cooper-Schrieffer theory of superconductivity breaks down.
Superconductivity and ferromagnetism can coexist in this regime. We identify
signatures of the competition between superconductivity and ferromagnetism in a
number of quantities: ground-state spin, conductance fluctuations when the
grain is weakly coupled to external leads and the thermodynamic properties of
the grain, such as heat capacity and spin susceptibility.Comment: 13 pages, 13 figures, Proceedings of the Conference on the Frontiers
of Quantum and Mesoscopic Thermodynamics (FQMT11
Study of High Energy Gamma-Quanta Beyond the Atmosphere
Measurements of primary cosmic radiation gamma quanta from Proton I and II satellite
Use of computers to exclude the influence of radiometer instability upon measurement results
A radiometer, practically insensitive to great fluctuations in the equipment amplification coefficient, was developed by dividing the useful signal by a reference signal and modulating the two signals at different frequencies. The signals are simultaneously separated by corresponding synchronous detectors and recorded over two channels. The operation is simplified by replacing the continuous signals by a sampling of discrete values, and using a digital computer. The four steps involved in the process are described and a block diagram is included. This technique not only directly connects the radiometer with the computer, but also records all data provided by the control and signal channels
Quantum search using non-Hermitian adiabatic evolution
We propose a non-Hermitian quantum annealing algorithm which can be useful
for solving complex optimization problems. We demonstrate our approach on
Grover's problem of finding a marked item inside of unsorted database. We show
that the energy gap between the ground and excited states depends on the
relaxation parameters, and is not exponentially small. This allows a
significant reduction of the searching time. We discuss the relations between
the probabilities of finding the ground state and the survival of a quantum
computer in a dissipative environment.Comment: 5 pages, 3 figure
Structural and Functional Organization of Photosynthetic Apparatus in Wild Halophites
The structural and molecular parameters of photosynthetic apparatus in plants with different strategies for the accumulation of salts were investigated. The objects of the study were euhalophytes (Salicornia perennans, Suaeda salsa, Halocnemum strobilaceum), a crynohalophyte (Limonium gmelinii) and a glycohalophyte (Artemisia santonica). The euhalophytes S. perennans and S. salsa belong to plants of the halosucculent type, while the other three species represent the xerophilic type. Larger cells with a great number of chloroplasts, a high content of membrane glycerolipids and unsaturated C18:3 fatty acid and smaller pigment and light-harvesting complexes characterize the features of euhalophytes with a succulent leaf type. Therefore, thefeatures of the halophyte photosynthetic apparatus structure are closely related to its functional indicators and are defined by a strategy in both the accumulation of salts and the method of water regime regulation.
Keywords: chlorophyll, lipids and fatty acids, photosynthetic apparatus, ultrastructure of chloroplast
How Abundant is Iron in the Core of the Perseus Cluster?
The analysis of Perseus data collected with the Medium Energy Concentrator
Spectrometer (MECS) on board Beppo-SAX shows that the ratio of the flux of the
8 keV line complex (dominated by Fe K emission) over the 6.8 keV line
complex (dominated by Fe K emission) is significantly larger than
predicted by standard thermal emission codes. Moreover the analysis of
spatially resolved spectra shows that the above ratio decreases with increasing
cluster radius. We find that, amongst the various explanations we consider, the
most likely requires the plasma to be optically thick for resonant scattering
at the energy of the Fe K line. We argue that if this is the case,
then measures of the iron abundance made using standard thermal emission codes,
that assume optically thin emission, can significantly underestimate the true
iron abundance. In the case of the core of Perseus we estimate the true
abundance to be 0.9 solar in a circular region with radius of
kpc and centered on NGC 1275. Finally we speculate that similar results may
hold for the core of other rich clusters.Comment: 19 pages, 3 Postscript figure
Assessment of psycho-emotional state of student with Mitral regurgitation and possible ways of its pharmacological correction
The article presents the results of psycho-emotional state assessment a person with Mitral regurgitation when he lies using the device for the physiological parameter record, and the possible ways of its pharmacological correction are offere
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