20,721 research outputs found
Two Higgs doublets to explain the excesses and
The two Higgs doublet model emerges as a minimal scenario in which to
address, at the same time, the excess at 750 GeV and the lepton
flavour violating decay into of the 125 GeV Higgs boson.
The price to pay is additional matter to enhance the rate, and a
peculiar pattern for the lepton Yukawa couplings. We add TeV scale vector-like
fermions and find parameter space consistent with both excesses, as well as
with Higgs and electroweak precision observables.Comment: 15 pages, 1 figure; v2: discussion of tau-->mu gamma added, leading
to an additional constraint. v3: references added, figure 1 recovered and
figure 2 adde
Suppression of Dephasing of Optically Trapped Atoms
Ultra-cold atoms trapped in an optical dipole trap and prepared in a coherent
superposition of their hyperfine ground states, decohere as they interact with
their environment. We demonstrate than the loss in coherence in an "echo"
experiment, which is caused by mechanisms such as Rayleigh scattering, can be
suppressed by the use of a new pulse sequence. We also show that the coherence
time is then limited by mixing to other vibrational levels in the trap and by
the finite lifetime of the internal quantum states of the atoms
Scotland, Catalonia and the “right” to self-determination: a comment suggested by Kathryn Crameri’s “Do Catalans Have the Right to Decide?
No abstract available
Storing images in warm atomic vapor
Reversible and coherent storage of light in atomic medium is a key-stone of
future quantum information applications. In this work, arbitrary
two-dimensional images are slowed and stored in warm atomic vapor for up to 30
s, utilizing electromagnetically induced transparency. Both the intensity
and the phase patterns of the optical field are maintained. The main limitation
on the storage resolution and duration is found to be the diffusion of atoms. A
techniqueanalogous to phase-shift lithography is employed to diminish the
effect of diffusion on the visibility of the reconstructed image
Regions of beta 2 and beta 4 responsible for differences between the steady state dose-response relationships of the alpha 3 beta 2 and alpha 3 beta 4 neuronal nicotinic receptors
We constructed chimeras of the rat beta 2 and beta 4 neuronal nicotinic subunits to locate the regions that contribute to differences between the acetylcholine (ACh) dose-response relationships of the alpha 3 beta 2 and alpha 3 beta 4 receptors. Expressed in Xenopus oocytes, the alpha 3 beta 2 receptor displays an EC50 for ACh approximately 20-fold less than the EC50 of the alpha 3 beta 4 receptor. The apparent Hill slope (n(app)) of alpha 3 beta 2 is near one whereas the alpha 3 beta 4 receptor displays an n(app) near two. Substitutions within the first 120 residues convert the EC50 for ACh from one wild-type value to the other. Exchanging just beta 2:104-120 for the corresponding region of beta 4 shifts the EC50 of ACh dose-response relationship in the expected direction but does not completely convert the EC50 of the dose- response relationship from one wild-type value to the other. However, substitutions in the beta 2:104-120 region do account for the relative sensitivity of the alpha 3 beta 2 receptor to cytisine, tetramethylammonium, and ACh. The expression of beta 4-like (strong) cooperativity requires an extensive region of beta 4 (beta 4:1-301). Relatively short beta 2 substitutions (beta 2:104-120) can reduce cooperativity to beta 2-like values. The results suggest that amino acids within the first 120 residues of beta 2 and the corresponding region of beta 4 contribute to an agonist binding site that bridges the alpha and beta subunits in neuronal nicotinic receptors
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