In this experiment, BECs absorb X-rays. *Rydberg excitation of a Bose-Einstein condensate* <http://www.freerepublic.com/focus/f-chat/3024348/posts> *arxiv.org ^ <http://www.freerepublic.com/%5Ehttp://arxiv.org/pdf/1203.1261v1.pdf> * | March 2012 | M. Viteau1, M. Bason1, J. Radogostowicz2;3, N. Malossi1;2, O. Morsch1, D. Ciampini1;2;3, and E. Arim
Posted on *Mon 27 May 2013 10:56:04 AM PDT* by *Kevmo * <http://www.freerepublic.com/%7Ekevmo/> Rydberg excitation of a Bose-Einstein condensate http://arxiv.org/pdf/1203.1261v1.pdf We have performed two-photon excitation via the 62P3=2 state to n=50-80 S or D Rydberg state in Bose-Einstein condensates of rubidium atoms. The Rydberg excitation was performed in a quartz cell, where electric fields generated by plates external to the cell created electric charges on the cell walls. Avoiding accumulation of the charges and realizing good control over the applied electric field was obtained when the fields were applied only for a short time, typically a few microseconds. Rydberg excitations of the Bose-Einstein condensates loaded into quasi one-dimensional traps and in optical lattices have been investigated. The results for condensates expanded to different sizes in the one-dimensional trap agree well with the intuitive picture of a chain of Rydberg excitations controlled by the dipole-dipole interaction. The optical lattice applied along the one-dimensional geometry produces localized, collective Rydberg excitations controlled by the nearest-neighbour blockade. PACS numbers: 03.65.Xp, 03.75.Lm ………………… V. CONCLUSIONS We have demonstrated the controlled preparation of Rydberg excitations in large ensembles of ultracold atoms forming structures of localized collective excita- tions, either self-generated by the long-range interactions between Rydberg atoms or imposed by an optical lattice. Our results can straightforwardly be extended to two- and three-dimensional lattice geometries and to even larger lattice spacings that will allow selective Rydberg excitation on a single site. Furthermore, appropriate detection techniques such as microchannel plates should allow direct observation of the distribution of Rydberg excitations in the lattice. Classical and quantum correlations, and highly en- tangled collective states are expected to be created, as pointed out in [42] for one dimensional Rydberg gases and in [43] for one-dimensional optical lattices. Our results pave the way towards their controlled creation. On Thu, Jul 24, 2014 at 3:31 PM, Jones Beene <[email protected]> wrote: > Downshifting of gammas- all the way to phonons, without going through > the x-ray level (which is detectable) is especially absurd, when one > realizes that there is not a single experiment in all of physics that > demonstrates any significant level of downshifting at all. > > > > It is complete science fiction. Bad science fiction. > > > > > > *From:* Bob Higgins > > > > I did not think I originated it, but I am convinced of it. This came up > in particular for the proposed shielding effect by WL. It is a similar > issue. Once the atom is excited with high energy to be released very > quickly, it is difficult for pretty much any de-excitation mechanism to be > 100% effective in reducing the energy to low level quanta. In the WL case, > I doubt that such a mechanism could be even 50% effective from geometry > alone. > > > > But you are correct that this argument may not apply in all such cases. > > > > I haven't seen a case yet where I believe that the downshifting mechanism > or blocking mechanism could be 100% effective. That doesn't at all prove > there isn't a scenario which could be 100% effective - I just can't see it. > > > > Bob > > > > On Thu, Jul 24, 2014 at 3:14 PM, Axil Axil <[email protected]> wrote: > > The problem is that after the high energy gamma is created, it is not > plausible that 100% of the quanta are downshifted - some will fail in this > post-fusion downshifting and be released as high energy. > > > > > > Where dis this assumption come from? > > >
