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Organ biobanking is the pending subject of cryopreservation. Although the problem is multifaceted, advances in recent decades have largely related it to achieving rapid and uniform rewarming of cryopreserved samples. This is a physical challenge largely investigated in past in addition to cryoprotectant toxicity studies, which have also shown a great amount of advancement. This paper presents a proof-of-principle, based on the nematode Caenorhabditis elegans, of a technology capable of performing such a function: high intensity focused ultrasound. Thus, avoiding the problem of recrystallization, this worm, in its adult state, preserved at − $$80\;^\circ{\rm C}$$ 80 ∘ C , has been systematically brought back to life after being heated with High Intensity Focused Ultrasound (HIFU) waves. The great advantage of this technology is that it is scalable; in addition, rewarming can be monitored in real time by MRI thermography and can be controlled by acoustic interferometry. We anticipate that our findings are the starting point for a possible approach to rewarming that can be used for cryopreservation of millimeter scale systems: either alone or in combination with other promising ways of heating, like nanowarming or dielectric heating, the present technology provides new ways of solving the physical aspects of the problem of recrystallization in cryopreservation, opening the door for the long-term storage of larger samples.

We continue the study of parametric down conversion within the framework of the Wigner representation, by using a Maxwellian approach developed in a recent paper [A. Casado et al., Eur. Phys. J. D 11, 465 (2000)]. This gives a mechanism, inside the crystal, for the production of the down-converted radiation. We obtain the electric field to second order in the coupling constant by using the Green's function method, and compare our treatment with the standard Hamiltonian approach. The spectrum of the down-converted radiation is calculated as a function of the parameters of the nonlinear crystal (in particular the length) and the radius of the pumping beam.

By following the analysis of De Caro and Garuccio [Phys. Rev. A 54, 174 (1996)], we show that the factorable state vector produced with a beam-splitter set on the paths of parametric down-converted photons violates some new inequalities that we deduce from local realism. These inequalities are more stringent than those used up to now in the discussion of such phenomena.

The conceptual problems that quantum mechanics poses has been noticed by numerous authors [1]. From the early beginnings it has been questioned even by some of its creators: Planck, Eherenfest, Einstein, Schrodinger and de Broglie [2-9]. The problem of the collapse of the wave function, its compatibility with special relativity, the question of its completeness, the meaning of the uncertainty relations, etc., are some of the points that have still not received a satisfactory answer. Certainly a large part of these problems would not exist if the theory could get a realistic and local formulation. On the other hand, quantum mechanics has proven to be extremely good from a pragmatic point of view. It seems to make sense to create a theory that at the same time is realistic and local and close to quantum mechanics, without coinciding exactly with it, because Bell's theorem [10] forbids explicitly this possibility. The hope of a realistic and local explanation of the world has not been excluded experimentally. However, since the most extended opinion in the scientific community is just the opposite, we shall explain once more where lies the error of their arguments. Section 1 deals with the weak and strong Bell's inequalities, quoting the different approaches to solve the EPR paradox. In Sec. 2 one of these approaches is developed, the one usually called “Enhancement” or “Variable-Detection-Probability Model.” In Sec. 3, and with the same approach, we display one of these models that is basically an enrichment of the Einstein-de Broglie's version of quantum mechanics.

We report here the results obtained by applying a local and realistic theory to photon intereference phenomena [1], recently observed in a set of experiments performed by Mandel and co-workers [4,6]. In these papers Mandel discarded the possibility of a rational explanation of his results, in the sense that the high visibility obtained was according to him far above the maximum allowed by a “classical” theory. We shall see how a small set of hypotheses, highly plausible for a realistically minded physicist, drives us to a large visibility in agreement with these experiments.