14,511 research outputs found
Maximal entanglement of two spinor Bose-Einstein condensates
Starting with two weakly-coupled anti-ferromagnetic spinor condensates, we
show that by changing the sign of the coefficient of the spin interaction,
, via an optically-induced Feshbach resonance one can create an
entangled state consisting of two anti-correlated ferromagnetic condensates.
This state is maximally entangled and a generalization of the Bell state from
two anti-correlated spin-1/2 particles to two anti-correlated spin atomic
samples, where is the total number of atoms.Comment: 5 pages, 3 figures, accepted for publication in PR
Universality of Brunnian (-body Borromean) four and five-body systems
We compute binding energies and root mean square radii for weakly bound
systems of and identical bosons. Ground and first excited states of
an -body system appear below the threshold for binding the system with
particles. Their root mean square radii approach constants in the limit of weak
binding. Their probability distributions are on average located in
non-classical regions of space which result in universal structures. Radii
decrease with increasing particle number. The ground states for more than five
particles are probably non-universal whereas excited states may be universal
Structure of exotic three-body systems
The classification of large halos formed by two identical particles and a
core is systematically addressed according to interparticle distances. The
root-mean-square distances between the constituents are described by universal
scaling functions obtained from a renormalized zero-range model. Applications
for halo nuclei, Li and Be, and for atomic He are briefly
discussed. The generalization to four-body systems is proposed.Comment: Contribution to the International workshop "Critical Stability of
Few-Body Quantum Systems". To be published in "Few-Body Systems
A doorway to Borromean halo nuclei: the Samba configuration
We exploit the possibility of new configurations in three-body halo nuclei -
Samba type - (the neutron-core form a bound system) as a doorway to Borromean
systems. The nuclei Be, B, N and F are of such
nature, in particular N with a half-life of 37.7 s and a halo radius of
6.07 fm is an excellent example of Samba-halo configuration. The fusion below
the barrier of the Samba halo nuclei with heavy targets could reveal the so far
elusive enhancement and a dominance of one-neutron over two-neutron transfers,
in contrast to what was found recently for the Borromean halo nucleus He +
U.Comment: Accepted for publication in Modern Physics Letters
Four-boson scale near a Feshbach resonance
We show that an independent four-body momentum scale drives the
tetramer binding energy for fixed trimer energy (or three-body scale
) and large scattering length (). The three- and four-body forces
from the one-channel reduction of the atomic interaction near a Feshbach
resonance disentangle and . The four-body independent
scale is also manifested through a family of Tjon-lines, with slope given by
for . There is the possibility of a new
renormalization group limit cycle due to the new scale
Understanding the tsunami with a simple model
In this paper, we use the approximation of shallow water waves (Margaritondo
G 2005 Eur. J. Phys. 26 401) to understand the behaviour of a tsunami in a
variable depth. We deduce the shallow water wave equation and the continuity
equation that must be satisfied when a wave encounters a discontinuity in the
sea depth. A short explanation about how the tsunami hit the west coast of
India is given based on the refraction phenomenon. Our procedure also includes
a simple numerical calculation suitable for undergraduate students in physics
and engineering
Superconducting pi qubit with a ferromagnetic Josephson junction
Solid-state qubits have the potential for the large-scale integration and for
the flexibility of layout for quantum computing. However, their short
decoherence time due to the coupling to the environment remains an important
problem to be overcome. We propose a new superconducting qubit which
incorporates a spin-electronic device: the qubit consists of a superconducting
ring with a ferromagnetic pi junction which has a metallic contact and a normal
Josephson junction with an insulating barrier. Thus, a quantum coherent
two-level state is formed without an external magnetic field. This feature and
the simple structure of the qubit make it possible to reduce its size leading
to a long decoherence time.Comment: 4 pages, 3 figure
Role of the Calcium Plateau in the Neuronal Injury and Behavioral Morbidities Following Organophosphate Intoxication
Organophosphate (OP) chemicals include nerve agents and pesticides, and there is a growing concern of OP based chemical attacks against civilians. Current antidotes are essential in limiting immediate mortality associated with OP exposure. However, further research is needed to identify molecular mechanisms underlying long-term neurological deficits following survival of OP toxicity in order to develop effective therapeutics. We have developed rat survival models of OP induced status epilepticus (SE) that mimic chronic mortality and morbidity following OP intoxication. We have observed significant elevations in hippocampal calcium levels after OP SE that persisted for weeks following initial survival. Drugs inhibiting intracellular calcium-induced calcium release such as dantrolene, levetiracetam, and carisbamate lowered OP-SE mediated protracted calcium elevations. Given the critical role of calcium signaling in modulating behavior and cell-death mechanisms, drugs targeted at preventing the development of the calcium plateau could enhance neuroprotection, help reduce morbidity and improve outcome following survival of OP SE
Characterization of the regulatory region of bovine mucin 2 (MUC2) gene.
Na publicação: E. O. Melo
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