Data	Titolo	Relatore
7 febbraio ore 10 ed.A p.2	Backward Causation and Odd values revealed by Weak Quantum Measurements sunto >>> An EPR (Einstein-Podolsky-Rosen) experiment is studied where each particle undergoes a few weak measurements along some pre-set spin orientations, whose outcomes are individually recorded. Then the particle undergoes a strong measurement along a spin orientation freely chosen at the last moment. Bell-inequality violation is expected between the two final strong measurements within each EPR pair. At the same time, agreement is expected between these measurements and the earlier weak ones within the pair. A contradiction thereby ensues: i) Bell's theorem forbids spin values to exist prior to the choice of the spin-orientation to be measured; ii) A weak measurement cannot determine the outcome of a successive strong one; and iii) Indeed no disentanglement is inflicted by the weak measurements; yet iv) The weak measurements' outcomes agree with those of the strong ones. The most reasonable resolution seems to be that of the Two-State-Vector Formalism (TSVF), namely, that the experimenter's choice has been encrypted within the weak measurement's outcomes, even before the experimenter themselves knows what their choice will be. These results are complemented by another choices of pre- and post-selection within quantum setups, where the detectors are shown to receive extraordinary momenta from individual photons. I review some alternative interpretations for these experiments and show that the TSVF gives the simplest and most self-consistent account. I close with a few comments on the applicability of these results for quantum cryptography and some experimental suggestions. Follow-up materials	Eliahu Cohen Tel-Aviv University, Israel
15 febbraio ore 10 ed.D p.1	Transition metal based magnetocaloric materials for cooling applications: a fundamental approach sunto >>> Solid state cooling technology as alternative to gas compression is being studied for years. Research on the magnetocaloric effect has flourished due to the observation of high entropy changes around a variety of first order magnetic phase transitions. More than that, the discovery of materials in which the phase transition can be tuned through chemical substitutions to temperatures around and above room temperature made commercial prototypes feasible and competitive. Amongst potential working materials, transition metal-based compounds hold special interest due to their low cost and the variety of physical phenomena giving rise to magneto-structural couplings and phase transitions. During my talk I will present my research on several transition-metal based materials which are promising for applications. In these compounds the different types of magneto-structural coupling which give rise to giant magnetocaloric effects have been studied. The use of several standard and non-standard characterization techniques, such as high pressure X-ray diffraction and magnetometry, has provided not only a better understanding of the physical phenomena behind the magnetocaloric effect but has also revealed new features of interest for applications.	Luana Caron Fundamental Aspects of Materials and Energy Group Faculty of Applied Sciences Delft University of Technology (TU Delft), The Netherlands
12 marzo ore 14:30 ed.D p.1	Probabilistic aspects of magnetization relaxation in single-domain nanomagnets sunto >>> A single-domain nanomagnet is a basic example of system where relaxation from high to low energy is probabilistic in nature even when thermal fluctuations are neglected. The reason is the presence of multiple stable states combined with extreme sensitivity to initial conditions. It is demonstrated that for this system the probability of relaxing from high energies to one of the stable magnetization orientations can be tuned to whatever desired value between 0 and 1 by applying a small transverse magnetic field of appropriate amplitude. In particular, exact analytical predictions are derived for the conditions under which the probability of reaching one of the stable states becomes exactly 0 or 1. Under these conditions, magnetization relaxation is totally insensitive to initial conditions and the final state can be predicted with certainty, a feature that could be exploited to devise novel magnetization switching strategies or novel methods for the measurement of the magnetization damping constant.	Giorgio Bertotti INRIM

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