Resource
2016 EN
PANDA Collaboration · B. Singh · W. Erni
+502 more
Simulation results for future measurements of electromagnetic proton formfactors at \PANDA (FAIR) within the PandaRoot software framework are reported.The statistical precision with which the proton form factors can be determinedis estimated. The signal channel $\bar p p \to e^+ e^-$ is studied on the basisof two different but consistent procedures. The suppression of the mainbackground channel, $\textit{i.e.}$ $\bar p p \to \pi^+ \pi^-$, is studied.Furthermore, the background versus signal efficiency, statistical andsystematical uncertainties on the extracted proton form factors are evaluatedusing two different procedures. The results are consistent with those of aprevious simulation study using an older, simplified framework. However, aslightly better precision is achieved in the PandaRoot study in a large rangeof momentum transfer, assuming the nominal beam conditions and detectorperformance.
Resource
2016 EN
Simone Giombi
In these lectures we give an overview of the duality between gravitationaltheories of massless higher spin fields in AdS and large N vector models. Wefirst review the original higher spin/vector model duality conjectured byKlebanov and Polyakov, and then discuss its generalizations involving vectormodels coupled to Chern-Simons gauge fields. We proceed to review some aspectsof the theory of massless higher spins, starting with the Fronsdal equationsfor free fields and moving on to the fully non-linear Vasiliev equations infour dimensions. We end by reviewing some recent tests of the higherspin/vector model duality at the level of correlation functions and one-looppartition functions.
Resource
2016 EN
J. Järvinen · J. Ahokas · S. Sheludyakov
+5 more
We present the results of experiments on dynamic nuclear polarization andrelaxation of 75As in silicon crystals. Experiments are performed in strongmagnetic fields of 4.6 T and temperatures below 1 K. At these conditions donorelectron spins are fully polarized, and the allowed and forbidden ESRtransitions are well resolved. We demonstrate effective nuclear polarization of75As nuclei via the Overhauser effect on the time scale of several hundredseconds. Excitation of the forbidden transitions leads to a polarizationthrough the solid effect. The relaxation rate of donor nuclei has strongtemperature dependence characteristic of Orbach process.
Resource
2016 EN
Petr V. Borisyuk · Oleg S. Vasiliev · Yaroslav V. Zhumagulov
+4 more
The technique is presented of restoring the electronic density of states ofthe valence band from data of X-ray photoelectron spectroscopy. The originalityof the technique consists in using a stochastic procedure to solve an integralequation relating the density of states and the experimental X-rayphotoelectron spectra. The results are presented for bulk sample of gold andnanoclusters of tantalum; the possibility of using the results to determine thedensity of states of low-dimensional structures, including ensembles of metalnanoclusters, is demonstrated.
Resource
2016 EN
Farid Ablayev · Sergey Andrianov · Danila Fetisov
+4 more
We propose a model of a programmable quantum processing device realizablewith existing nanophotonic technologies and which can be viewed as a basis fornew high performance hardware architectures. We present protocols and theirphysical implementation on the controlled photon transfer for executing basicsingle-qubit and multi-qubit gates. The possible operation of this quantumcomputer scheme is analyzed. The physical architecture is then formalized by amathematical model of the Quantum Processing Unit (QPU), which is used as abasis for the Quantum Programming Framework that makes it possible to performuniversal quantum computations in a multitasking environment.
Resource
2016 EN
Mansur Ziatdinov
The notion of quantum hashing formalized by F. Ablayev and A. Vasiliev in2013. F. Ablayev and M. Ablayev in 2014 introduced the notion of quantum hashgenerator which is convenient technical tool for constructing quantum hashfunc- tions. M. Ziatdinov in 2014 presented group approach for constructingquantum hash functions. All these mentioned above results present constructionsof quan- tum hash functions based on abelian groups. This paper continue theresearch on quantum hashing. Our approach allows us to construct quantum hashfunction working on any (finite) group. Also our approach allows us toconstruct quantum hash functions based on classical hash function from $NC^1$.
Journals
2015 EN
Kazak N. V. · Platunov M. S. · Knyazev Yu. V.
+10 more
Single‐crystalline MgFeBO 4, Mg 0.5 Co 0.5 FeBO 4 , and CoFeBO 4 have been grown by the flux method. The samples have been characterized by X‐ray spectral analysis, X‐ray diffraction, and X‐ray absorption spectroscopy. The X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) spectra have been measured at the Fe and Co K ‐edges over a wide temperature range (6.5–300 K). The composition, the charge state, and local environment of both Fe and Co atoms have been determined. The effects of Co substitution for Mg on the local structural distortions have been revealed experimentally and the MO bond anisotropy has been found.
Journals
2015 EN
Ashwin Hegde · Per Kraus · Eric Perlmutter
We develop tools for the efficient evaluation of Wilson lines in 3D higherspin gravity, and use these to compute entanglement entropy in thehs$[\lambda]$ Vasiliev theory that governs the bulk side of the dualityproposal of Gaberdiel and Gopakumar. Our main technical advance is thedetermination of SL(N) Wilson lines for arbitrary $N$, which, in suitablecases, enables us to analytically continue to hs$[\lambda]$ via $N \rightarrow-\lambda$. We apply this result to compute various quantities of interest,including entanglement entropy expanded perturbatively in the background higherspin charge, chemical potential, and interval size. This includes a computationof entanglement entropy in the higher spin black hole of the Vasiliev theory.These results are consistent with conformal field theory calculations. We alsoprovide an alternative derivation of the Wilson line, by showing how it arisesnaturally from earlier work on scalar correlators in higher spin theory. Thegeneral picture that emerges is consistent with the statement that the SL(N)Wilson line computes the semiclassical $W_N$ vacuum block, and our resultsprovide an explicit result for this object.
Journals
2015 EN
Jun Bourdier · Nadav Drukker
We present a simple construction of solutions to the supersymmetric higherspin theory based on solutions to bosonic theories. We illustrate this for thecase of the Didenko-Vasiliev solution in arXiv:0906.3898, for which we havefound a striking simplification where the higher-spin connection takes thevacuum value. Studying these solutions further, we check under which conditionsthey preserve some supersymmetry in the bulk, and when they are compatible withthe boundary conditions conjectured to be dual to certain 3d SUSYChern-Simons-matter theories. We perform the analysis for a variety of theorieswith $\mathcal{N}$ = 2, $\mathcal{N}$ = 3, $\mathcal{N}$ = 4 and $\mathcal{N}$= 6 and find a rich spectrum of $1/4$, $1/3$ and $1/2$-BPS solutions.
Journals
2015 EN
Euihun Joung · Karapet Mkrtchyan
The higher-spin (HS) algebras so far known can be interpreted as thesymmetries of the minimal representation of the isometry algebra. Afterdiscussing this connection briefly, we generalize this concept to any classicalLie algebras and consider the corresponding HS algebras. For sp(2N) and so(N),the minimal representations are unique so we get unique HS algebras. For sl(N),the minimal representation has one-parameter family, so does the correspondingHS algebra. The so(N) HS algebra is what underlies the Vasiliev theory whilethe sl(2) one coincides with the 3D HS algebra hs[lambda]. Finally, we derivethe explicit expression of the structure constant of these algebras --- moreprecisely, their bilinear and trilinear forms. Several consistency checks arecarried out for our results.