12,990 research outputs found
Magnetothermal properties of molecule-based materials
We critically review recent results obtained by studying the low-temperature
specific heat of some of the most popular molecular magnets. Perspectives of
this field are discussed as well.Comment: 12 pages text + 14 pages figures, Submitted as "feature article" to
Journal of Materials Chemistr
Topological responses from chiral anomaly in multi-Weyl semimetals
Multi-Weyl semimetals are a kind of topological phase of matter with discrete
Weyl nodes characterized by multiple monopole charges, in which the chiral
anomaly, the anomalous nonconservation of an axial current, occurs in the
presence of electric and magnetic fields. Electronic transport properties
related to the chiral anomaly in the presence of both electromagnetic fields
and axial electromagnetic fields in multi-Weyl semimetals are systematically
studied. It has been found that the anomalous Hall conductivity has a
modification linear in the axial vector potential from inhomogeneous strains.
The axial electric field leads to an axial Hall current that is proportional to
the distance of Weyl nodes in momentum space. This axial current may generate
chirality accumulation of Weyl fermions through delicately engineering the
axial electromagnetic fields even in the absence of external electromagnetic
fields. Therefore, this work provides a nonmagnetic mechanism of generation of
chirality accumulation in Weyl semimetals and might shed new light on the
application of Weyl semimetals in the emerging field of valleytronics.Comment: 13 pages, 2 tables, 2 figures, accepted by Physical Review
Chiral plasma instability and primordial Gravitational wave
It is known that cosmic magnetic field, if present, can generate anisotropic
stress in the plasma and hence, can act as a source of gravitational waves.
These cosmic magnetic fields can be generated at very high temperature, much
above electroweak scale, due to the gravitational anomaly in presence of the
chiral asymmetry. The chiral asymmetry leads to instability in the plasma which
ultimately leads to the generation of magnetic fields. In this article, we
discuss the generation of gravitational waves, during the period of
instability, in the chiral plasma sourced by the magnetic field created due to
the gravitational anomaly. We have shown that such gravitational wave will have
a unique spectrum. Moreover, depending on the temperature of the universe at
the time of its generation, such gravitational waves can have a wide range of
frequencies. We also estimate the amplitude and frequency of the gravitational
waves and delineate the possibility of its detection by future experiments like
eLISA.Comment: 8 pages, 2 figure
Primakoff Physics for CERN COMPASS Hadron Beam: Hadron Polarizabilities, Hybrid Mesons, Chiral Anomaly, Meson Radiative Transitions
We describe a hadron physics program attainable with a partially instrumented
CERN COMPASS spectrometer, involving tracking detectors and moderate-size
ECAL2/HCAL2 calorimeters. COMPASS can realize a state-of-the-art hadron beam
physics program based on hadron polarizability, hybrid mesons, chiral anomaly,
and meson radiative transition studies. We review here the physics motivation
for this hadron beam program. We describe the beam, detector, trigger
requirements, and hardware/software requirements for this program. The triggers
for all this physics can be implemented for simultaneous data taking. The
program is based on using a hadron beam (positive/negative pion, kaon, proton)
in COMPASS.Comment: Contribution to the Proceedings of the Charles U./JINR and
International U. (Dubna) CERN COMPASS Summer School, Charles University,
Prague, Czech Republic, August 1997, Eds. M. Chavleishvili and M. Finger Tel
Aviv U. Preprint TAUP TAUP-2473-98. 26 pages, 11 figures, late
Starspots and spin-orbit alignment for Kepler cool host stars
The angle between the spin axis of the host star and the orbit of its planets
(i.e., the stellar obliquity) is precious information about the formation and
evolution of exoplanetary systems. Measurements of the Rossiter-McLaughlin
effect revealed that many stars that host a hot-Jupiter have high obliquities,
suggesting that hot-Jupiter formation involves excitation of orbital
inclinations. In this contribution we show how the passage of the planet over
starspots can be used to measure the obliquity of exoplanetary systems. This
technique is used to obtain - for the first time - the obliquity of a system
with several planets that lie in a disk, Kepler-30, with the result that the
star has an obliquity smaller than 10 degrees. The implications for the
formation of exoplanetary systems, in particular the hot-Jupiter population,
are also discussed.Comment: To appear in special edition of AN, proceedings of the Cool Stars 17
conference, Barcelona June 201
How efficient is an integrative approach in archaeological geophysics? Comparative case studies from Neolithic settlements in Thessaly (Central Greece)
The geophysical prospection of Neolithic tells imposes specific challenges due to the preservation and nature of the architectural context and the multiple, usually disturbed, soil strata. Contrary to the usual application of a single method, this paper deals with the advantages of using an integrated geophysical approach through the employment of various methodologies to map the Neolithic cul-tural and environmental landscape of Thessalian tells (magoules) in Central Greece. The success and failure of each method in resolving the various features of the magoules are discussed in detail, and as a whole, they demonstrate the benefits of a manifold geophysical prospection of the sites
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