LG11546
Compressing stars
In this work, purely stellar matter was compressed for the first time.
"Pieces of star"» are exotic beam of 56 Nickel, created in laboratory.
Thanks to a revolutionary gaseous target called MAYA, they reach an
excited state, the giant monopole resonance, in which nuclei " breath"
through a compression-dilatation mode. This breakthrough, which is also
valid for neutron-rich exotic nuclei, paves the way to the exploration of
the equation of state of asymmetric nuclear matter, which plays a pivotal
role in compression-explosion scenarios of supernovae, or in the structure
of pulsars and neutrons stars compressed by the gravitational attraction.
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LA11137
Mechanism of Accelerating Hydrogen Kinetics in Hydrogen Storage
Materials Revealed
The origin of slow hydrogen (H) kinetics in a hydride-based hydrogen
storage material and the mechanism of accelerating it by doping of
transition metal catalysts has been revealed for the first time by a
novel technique of muon spin rotation. This discovery would have a
strong influence over the choice/design of practical materials for
the future H-storages. In this work, it is shown that interstitial
hydrogen atoms in sodium alanate (a prototype hydride considered as a
strong candidate material for practical H-storage) fall into a
bonding state with negatively charged alanate ions. Such a state is
understood as a new variant of hydrogen bonding that has never been
considered previously in H-storage materials. Moreover, the Ti-
doping, which has been known for a decade to accelerate H-kinetics
but without any clear knowledge on the microscopic mechanism, turns
out to reduce the kinetic barrier for hydrogen to move from the H-
bonding state to the octahedral interstitial site where H atoms are
mobile, thus accelerating the H-kinetics.
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LG11405
"Don’t disturb – it’s a classical correlation!"
Correlations are ubiquitous – both in classical and quantum worlds. Our work concerns with distinguishing these two. Consider Alice and Bob sharing a quantum state. When Alice performs measurement on her part of the system, Bob’s state is modified, in general. But if the correlation happens to be classical, Alice must be able to find an optimal measurement scheme leaving the overall state intact! In contrast, quantum correlated states are sensitive to partial measurements. Quantum discord proposed by Ollivier and Zurek (and an independently similar suggestion by Henderson and Vedral), as a measure of quantumness, aims towards quantifying the minimum disturbance upon an optimized partial measurement by Alice. However, such a scheme leads to a conflicting result: quantum discord (and another variant, quantum deficit, proposed by Rajagopal and Rendell) yield non-zero values for a large class of separable states - traditionally considered to be classically correlated. This raises a question on the division of composite states into separable and non-separable (quantum entangled) and even on whether quantumness of correlation is more general than quantum entanglement. Since quantum entanglement is considered to be an important resource in quantum communication and computation, this question needs a clear answer. We approach this issue by introducing a third party Charlie - but leaving the original shared state between Alice and Bob unaltered - in defining a new measure. This is designed to quantify the least disturbance on the state of Alice-Bob when an optimal partial measurement is performed at Alice-Charlie end. Strikingly, our quantumness vanishes if Alice-Bob system is separable - unlike the other measures mentioned above – as Alice and Charlie together can always end up with an optimal measurement scheme under which the Alice-Bob state remains insensitive! Another remarkable identification is that our measurement-based quantification is identically equal to relative entropy of entanglement - a well-known measure of quantum entanglement. Our proposal thus leads to a conflict free union of quantumness of correlation with quantum entanglement itself.
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LF11340
Effects of interactions in the spin-polarized transport through Aharonov-Bohm-Casher interferometers.
The Aharonov-Bohm (AB) effect, and its charge-spin dual, the Aharonov-Casher
(AC) effect, are purely quantum mechanical phenomena arising from the
interaction between the electromagnetic field and the electronic charge
or magnetic moment (spin), when the electron performs a closed path.
Experiments in mesoscopic rings pierced by a magnetic or electric field have
beautifully demonstrated these one-particle effects as oscillations in
the conductance through rings.
In this work, we investigate theoretically the situation when the AB and
AC effects take place simultaneously in a ring with embedded quantum
dots (QDs). Due to strong Coulomb repulsion, a QD can have a localized
magnetic moment with an odd number of electrons. At very low
temperatures, the antiferromagnetic exchange interaction between the
magnetic moment and the spin of conduction electrons leads to the total
screening of local moment, a highly non-trivial many-body phenomenon
known as Kondo effect. As a consequence of the interplay between Kondo
and interference effects. very modest electric and magnetic fields can lead
to high spin polarizations. This can be useful in the search for
electronic devices controlled by the spin instead of the charge of the
electrons (spintronics).
