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We discuss a number of suggested explanations for observed discrepancies between theories of the quantum corrections to conduction, and recent magnetoresistance experiments on bulk metallic glasses. We emphasize the importance of competing effects, particularly the influence of magnetic impurities. Data showing these effects are presented and analyzed using a theory of Béal-Monod and Weiner to account for the direct magnetoresistance from the spin scattering and the magnetic field dependence of the spin-flip dephasing rate. Throughout, we provide useful numerical procedures for the efficient evaluation of the theoretical expressions used in analyzing such data, and point out that some theoretical expressions must be altered when considering strongly enhanced paramagnetic systems

The violation of baryon number, B , is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron–antineutron oscillation ( n → n ̄ ) via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state ( n → [ n ′ , n ̄ ′ ] → n ̄ ), and neutron disappearance (n → n′); the effective Δ B = 0 process of neutron regeneration ( n → [ n ′ , n ̄ ′ ] → n ) is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.

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This report, prepared for the Community Planning Study -Snowmass 2013 -summarizes the theoretical motivations and the experimental efforts to search for baryon number violation, focussing on nucleon decay and neutron-antineutron oscillations. Present and future nucleon decay search experiments using large underground detectors, as well as planned neutron-antineutron oscillation search experiments with free neutron beams are highlighted. OverviewBaryon Number, B, is observed to be an extremely good symmetry of Nature. The stability of ordinary matter is attributed to the conservation of baryon number. The proton and the neutron are assigned B = +1, while their antiparticles have B = −1, and the leptons and antileptons all have B = 0. The proton, being the lightest of particles carrying a non-zero B, would then be absolutely stable if B is an exactly conserved quantum number. Hermann Weyl formulated the principle of conservation of baryon number in 1929 primarily to explain the stability of matter [1]. Weyl's suggestion was further elaborated by Stueckelberg [2] and Wigner [3] over the course of the next two decades. The absolute stability of matter, and the exact conservation of B, however, have been questioned both on theoretical and experimental grounds. Unlike the stability of the electron which is on a firm footing as a result of electric charge conservation

The development of qualitatively new measurement capabilities is often a prerequisite for critical scientific and technological advances. The dramatic progress made by modern probe techniques to uncover the microscopic structure of matter is fundamentally rooted in our control of two defining traits of quantum mechanics: discreteness of physical properties and interference phenomena. Magnetic Resonance Imaging, for instance, exploits the fact that protons have spin and can absorb photons at frequencies that depend on the medium to image the anatomy and physiology of living systems. Scattering techniques, in which photons, electrons, protons or neutrons are used as probes, make use of quantum interference to directly image the spatial position of individual atoms, their magnetic structure, or even unveil their concomitant dynamical correlations. None of these probes have so far exploited a unique characteristic of the quantum world: entanglement. Here we introduce a fundamentally new quantum probe, an entangled neutron beam, where individual neutrons can be entangled in spin, trajectory and energy. Its tunable entanglement length from nanometers to microns and energy differences from peV to neV will enable new investigations of microscopic magnetic correlations in systems with strongly entangled phases, such as those believed to emerge in unconventional superconductors. We develop an interferometer to prove entanglement of these distinguishable properties of the neutron beam by observing clear violations of both Clauser-Horne-Shimony-Holt and Mermin contextuality inequalities in the same experimental setup. Our work opens a pathway to a future era of entangled neutron scattering in matter. Text:A most amazing aspect of quantum reality is the possibility to share information non-locally between two or more spacelike separated subsystems, a "spooky action at a distance", as Einstein liked to call it and Bell epitomized in an inequality 1,2 . The fact that measuring compatible observables does not unveil predetermined physical properties, as pointed out by Kochen and Specker 3,4 , reveals the contextual nature of quantum measurements. Behind all these non-classical statistical correlations is the property of entanglement wherein "the state of the whole is more than the sum of its [constituent] parts'' 5 . Developing novel quantum probes that exploit these correlations as a means for investigating entanglement in matter could lead to novel insight into some of the most interesting materials studied today, such as frustrated magnets hosting quantum spin liquids and unconventional superconductors with strange metallic behavior 6 .

The electronic matrix element responsible for electron exchange in a series of metal dimers was calculated using ab initio wave functions. The distance dependence is approximately exponential for a large range of internuclear separations. A localized description, where the two nonorthogonal structures characterizing the electron localized at the left and right sites are each obtained self-consistently, is found to provide the best description of the electron exchange process. We find that Gaussian basis sets are capable of predicting the expected exponential decay of the electronic interactions even at quite large internuclear distances.926

A series of novel precursors for MOCVD of metallic copper have been synthesized and structurally characterized. These precursors are composed of Cu(hfacac)(2), which serves as a volatile source of Cu, and amino alcohols, which act as reductants and anchor firmly to the copper center through the amine unit. In some cases, a proton transfer from the coordinated alcohol to the hfacac ligand results in the formation of an alkoxide unit and the release of the free Hhfacac. Metallic copper films can be deposited by MOCVD at 300 degrees C without any external reductant. Crystal data: Cu(hfacac)(2).C(7)H(8) (-103 degrees C), a = 6.510(6) Å, b = 8.594(7) Å, c = 18.478(15) Å, orthorhombic space group Pmnn, Z = 2; Cu(hfacac)(2)(H(2)NCH(2)CH(2)OH) (-158 degrees C), a = 13.145(1) Å, b = 13.418(1) Å, c = 11.245(1) Å, alpha = 110.39(1) degrees, beta = 99.12(1) degrees, gamma = 97.90(1) degrees, triclinic space group P&onemacr;, Z = 4; [Cu(hfacac)(Me(2)NCH(2)CH(2)O)](2) (-153 degrees C), a = 9.259(2) Å, b = 12.011(3) Å, c = 6.304(1) Å, alpha = 91.19(1) degrees, beta = 106.66(1) degrees, gamma = 74.83(1) degrees, triclinic space group P&onemacr;, Z = 1; Cu(hfacac)[N(CH(2)CH(2)OH)(2)(CH(2)CH(2)O)].MeOH (-168 degrees C), a = 10.075(4) Å, b = 8.611(4) Å, c = 19.259(9) Å, beta = 99.82(2) degrees, monoclinic space group P2(1)/m, Z = 4.