5,746 research outputs found
Excitonic ordering in strongly correlated spin crossover systems: induced magnetism and excitonic excitation spectrum
The effects associated with interatomic hoppings of excitons and the
excitonic Bose condensate formation in the strongly correlated spin crossover
systems are considered in the framework of the effective Hamiltonian for the
two-band Kanamori model. The appearance of antiferromagnetic ordering due to
the exciton order is found even in the absence of interatomic exchange
interaction. The spectrum of excitonic excitations is calculated at various
points of the "temperature vs. crystal field" phase diagram. Outside the region
of exciton ordering, the spectrum has a gap, which vanishes at the boundary of
the exciton condensate phase. The non-uniform spectral weight distribution over
the Brillouin zone is found. The role of electron-phonon interaction is
discussed as well.Comment: 10 pages, 10 figure
Density-of-states picture and stability of ferromagnetism in the highly-correlated Hubbard model
The problem of stability of saturated and non-saturated ferromagnetism in the
Hubbard model is considered in terms of the one-particle Green's functions.
Approximations by Edwards and Hertz and some versions of the self-consistent
approximations based on the 1/z-expansion are considered. The account of
longitudinal fluctuations turns out to be essential for description of the
non-saturated state. The corresponding pictures of density of states are
obtained. "Kondo" density-of-states singularities owing to spin-flip processes
are analyzed. The critical electron concentrations for instabilities of
saturated ferromagnetism and paramagnetic state are calculated for various
lattices. Drawbacks of various approximations are discussed. A comparison with
the results of previous works is performed.Comment: 16 pages, 7 eps figure
Polarization-dependent electric potential distribution across nanoscale ferroelectric Hf0.5Zr0.5O2 in functional memory capacitors
Special features of the Be2He fragmentation in emulsion at an energy of 1.2~A~GeV
The results of investigations of the relativistic Be nucleus
fragmentation in emulsion which entails the production of two He fragments of
an energy of 1.2~A~GeV are presented. The results of the angular measurements
of the Be2He events are analyzed.
The BeBe+n fragmentation channel involving the Be decay from
the ground (0) and the first excited (2) states to two
particles is observed to be predominant.Comment: 10 pages, 6 figures, conference: Conference on Physics of Fundamental
Interactions, Moscow, Russia, 5-9 Dec 2005 (Author's translation
Search for decays of the B nucleus and Hoyle state in N nucleus dissociation
First results of an analysis to determine contribution of decays of the
unstable Be and B nuclei and the Hoyle 3-state to
dissociation of N 3He (+H) are presented. As the research
material, layers of nuclear track emulsion longitudinally exposed to 2.9
GeV/ N nuclei with at the JINR Nuclotron. Under the assumption that
the He and H fragments retain momentum per nucleon of the primary nucleus,
these unstable states are identified by the invariant mass calculated from the
emission angles of the fragments.Comment: Article materials were presented in the report by A.A. Zaitsev at LXX
International conference Nucleus - 2020,
https://indico.cern.ch/event/839985/contributions/3985257 To be published in
journal "Physics of Particles and Nuclei
Hard Probes in Heavy Ion Collisions at the LHC: Jet Physics
We discuss the importance of high-pT hadron and jet measurements in
nucleus-nucleus collisions at the CERN Large Hadron Collider.Comment: The writeup of the working group "Jet Physics" for the CERN Yellow
Report on "Hard Probes in Heavy Ion Collisions at the LHC", 123 pages.
Subgroup convenors: R. Baier, X.N. Wang, U.A. Wiedemann (theory) and I.P.
Lokhtin, A. Morsch (experiment). Editor: U.A. Wiedeman
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