The superfluid insulator transition of ultra-cold bosons in disordered 1d traps

We derive an effective quantum Josephson array model for a weakly interacting one-dimensional condensate that is fragmented into weakly coupled puddles by a disorder potential. The distribution of coupling constants, obtained from first principles, indicate that weakly interacting bosons in a disorder potential undergo a superfluid insulator transition controlled by a strong randomness fixed point [Phys. Rev. Lett. 93, 150402 (2004)]. We compute renormalization group flows for concrete realizations of the disorder potential to facilitate finite size scaling of experimental results and allow comparison to the behavior dictated by the strong randomness fixed point. The phase diagram of the system is obtained with corrections to mean-field results.Comment: 10 pages, 6 figures, expanded version including a calculation of a global phase diagra

HUMAN CLONING AND FDA REGULATION

In the February 27, 1997 issue of the journal Nature scientists from Scotland's Roslin Institute reported their successful efforts to clone an adult sheep using differentiated somatic cells from the animal. The clone, named Dolly, was the first instance of the successful cloning of an adult mammal. The shock waves created by the possible ramifications of this development were immediately felt around the world. For the first time, the cloning of an adult human being was no longer being considered an impossibility in mainstream scientific circles. Scientists, governments and laymen around the world were now forced to began considering the consequences of utilizing this new technology to clone adult human beings

Forensic metrology: its importance and evolution

Measurements play a fundamental role in nowadays forensic activities, especially in criminal justice. Guilt or innocence and the severity of a sentence do often depend upon the results of measurements. On the other hand, it is well-known that measurement results are always affected by uncertainty, so that any decision based on measurement results carries an implicit risk of being wrong: uncertainty helps in estimating this risk. If this concept is translated into the juridical world, it is quite immediate to recognize that uncertainty may quantify how reasonable is the doubt with which a verdict is rendered by the trier of facts. Unfortunately, forensic disciplines are still largely unaware of the basic, fundamental concepts of metrology. This paper is aimed at showing how forensic metrology is developing in different countries and reporting a few cases where metrology played a key role

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Abstract The conditions of indirect destructive oxidation of formic acid to CO 2 and H 2 O by OH · and HO 2 · intermediates generated from water and hydrogen peroxide in an electrolyzer without a membrane in the electrolytes with different pH are described. The effect of cathode current density and pH of the medium on the conversion of formic acid is investigated. It is shown that the conversion of formic acid in acidic electrolytes is higher than in alkaline ones and accounts for 99 % at pH 3.2. 766 IRINA S. VASILIEVA a nd VASILIY L. KORNIENKO decreases ecological attraction of this process for practical implementation. for A An an alog of the above-presented system can be the process in a membrane-free electrolyzer combining generation of radicals from water at the anode with the generation of H 2 O 2 from O 2 in the carbon-black gas diffusion cathode. It is known that under the conditions existing in electrochemical cell the radicals can be generated by means of anode oxidation of water in acidic medium according to reaction and in alkaline media according to reaction In addition, the generation of HO 2 radicals is possible via reactions [6] So, destructive oxidation of formic acid is possible without introducing Fe(II) salt in an electrochemical cell without a membrane, equi pped with gas diffusion carbon-black electrode, with anodic generation of highly reactive intermediates and . The goal of the present work is the investigation of destructive oxidation of formic acid by and intermediates generated in situ from H 2 O and H 2 O 2 in a membrane-free cell with electrolytes characterized by different pH values. EXPERIMENTAL A two-chamber glass electrolyzer cell with non-separated cathode and anode space consisting of the gas and electrolyte chambers was used to carry out electrolysis and to obtain H 2 O 2 . The cathode was a carbon-black gas diffusion hydrophobized electrode, and the anode was a platinum plate. The procedure of manufacturing gas diffusion electrodes was described in and in alkaline medium [10]: Model solutions with the initial concentration of formic acid in electrolyte 0.5 g/l were used for oxidation. The concentration of formic acid was determined by back titration with potassium permangan at

Theory of the many-body localization transition in one dimensional systems

We formulate a theory of the many-body localization transition based on a novel real space renormalization group (RG) approach. The results of this theory are corroborated and intuitively explained with a phenomenological effective description of the critical point and of the "badly conducting" state found near the critical point on the delocalized side. The theory leads to the following sharp predictions: (i) The delocalized state established near the transition is a Griffiths phase, which exhibits sub-diffusive transport of conserved quantities and sub-ballistic spreading of entanglement. The anomalous diffusion exponent $\alpha < 1/2$ vanishes continuously at the critical point. The system does thermalize in this Griffiths phase. (ii) The many-body localization transition is controlled by a new kind of infinite randomness RG fixed point, where the broadly distributed scaling variable is closely related to the eigenstate entanglement entropy. Dynamically, the entanglement grows as $\sim\log t$ at the critical point, as it also does in the localized phase. (iii) In the vicinity of the critical point the ratio of the entanglement entropy to the thermal entropy, and its variance (and in fact all moments) are scaling functions of $L/\xi$, where $L$ is the length of the system and $\xi$ is the correlation length, which has a power-law divergence at the critical point.Comment: Clarified presentation. 14 pages, 6 figure

Observation of many-body localization of interacting fermions in a quasi-random optical lattice

We experimentally observe many-body localization of interacting fermions in a one-dimensional quasi-random optical lattice. We identify the many-body localization transition through the relaxation dynamics of an initially-prepared charge density wave. For sufficiently weak disorder the time evolution appears ergodic and thermalizing, erasing all remnants of the initial order. In contrast, above a critical disorder strength a significant portion of the initial ordering persists, thereby serving as an effective order parameter for localization. The stationary density wave order and the critical disorder value show a distinctive dependence on the interaction strength, in agreement with numerical simulations. We connect this dependence to the ubiquitous logarithmic growth of entanglement entropy characterizing the generic many-body localized phase.Comment: 6 pages, 6 figures + supplementary informatio