5,848 research outputs found
Evidence for entanglement at high temperatures in an engineered molecular magnet
The molecular compound
[Fe(-oxo)(CHN)(CO)]
was designed and synthesized for the first time and its structure was
determined using single-crystal X-ray diffraction. The magnetic susceptibility
of this compound was measured from 2 to 300 K. The analysis of the
susceptibility data using protocols developed for other spin singlet
ground-state systems indicates that the quantum entanglement would remain at
temperatures up to 732 K, significantly above the highest entanglement
temperature reported to date. The large gap between the ground state and the
first-excited state (282 K) suggests that the spin system may be somewhat
immune to decohering mechanisms. Our measurements strongly suggest that
molecular magnets are promising candidate platforms for quantum information
processing
Final state interaction in with I=1/2 and 3/2 channels
The final state interaction contribution to decays is computed for the
channel within a light-front relativistic three-body model for
the final state interaction. The rescattering process between the kaon and two
pions in the decay channel is considered. The off-shell decay amplitude is a
solution of a four-dimensional Bethe-Salpeter equation, which is decomposed in
a Faddeev form. The projection onto the light-front of the coupled set of
integral equations is performed via a quasi-potential approach. The S-wave
interaction is introduced in the resonant isospin and the
non-resonant isospin channels. The numerical solution of the light-front
tridimensional inhomogeneous integral equations for the Faddeev components of
the decay amplitude is performed perturbatively. The loop-expansion converges
fast, and the three-loop contribution can be neglected in respect to the
two-loop results for the practical application. The dependence on the model
parameters in respect to the input amplitude at the partonic level is exploited
and the phase found in the experimental analysis, is fitted with an appropriate
choice of the real weights of the isospin components of the partonic amplitude.
The data suggests a small mixture of total isospin to the dominant
one. The modulus of the unsymmetrized decay amplitude, which presents a deep
valley and a following increase for masses above GeV, is fairly
reproduced. This suggests the assignment of the quantum numbers to the
isospin 1/2 resonance
Characterization and Glass Formation of JSC-1 Lunar and Martian Soil Simulants
The space exploration mission of NASA requires human and robotic presence for long duration beyond the low earth orbit (LEO), especially on Moon and Mars. Developing a human habitat or colony on these planets would require a diverse range of materials, whose applications would range from structural foundations, (human) life support, (electric) power generation to components for scientific instrumentations. A reasonable and cost-effective approach for fabricating the materials needed for establishing a self-sufficient human outpost would be to primarily use local (in situ) resources on these planets. Since ancient times, glass and ceramics have been playing a vital role on human civilization. A long term project on studying the feasibility of developing glass and ceramic materials has been undertaken using Lunar and Martian soil simulants (JSC-1) as developed by Johnson Space Center. The first step in this on-going project requires developing a data base on results that fully characterize the simulants to be used for further investigations. The present paper reports characterization data of both JSC-1 Lunar and JSC Mars-1 simulants obtained up to this time via x-ray diffraction analysis, scanning electron microscopy, thermal analysis (DTA, TGA) and chemical analysis. The critical cooling rate for glass formation for the melts of the simulants was also measured in order to quantitatively assess the glass forming tendency of these melts. The importance of the glasses and ceramics developed using in-situ resources for constructing human habitats on Moon or Mars is discussed
Influence of the external pressure on the quantum correlations of molecular magnets
The study of quantum correlations in solid state systems is a large avenue
for research and their detection and manipulation are an actual challenge to
overcome. In this context, we show by using first-principles calculations on
the prototype material KNaCuSiO that the degree of quantum
correlations in this spin cluster system can be managed by external hydrostatic
pressure. Our results open the doors for research in detection and manipulation
of quantum correlations in magnetic systems with promising applications in
quantum information science
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