Simplified models for photohadronic interactions in cosmic accelerators

We discuss simplified models for photo-meson production in cosmic accelerators, such as Active Galactic Nuclei and Gamma-Ray Bursts. Our self-consistent models are directly based on the underlying physics used in the SOPHIA software, and can be easily adapted if new data are included. They allow for the efficient computation of neutrino and photon spectra (from pi^0 decays), as a major requirement of modern time-dependent simulations of the astrophysical sources and parameter studies. In addition, the secondaries (pions and muons) are explicitely generated, a necessity if cooling processes are to be included. For the neutrino production, we include the helicity dependence of the muon decays which in fact leads to larger corrections than the details of the interaction model. The separate computation of the pi^0, pi^+, and pi^- fluxes allows, for instance, for flavor ratio predictions of the neutrinos at the source, which are a requirement of many tests of neutrino properties using astrophysical sources. We confirm that for charged pion generation, the often used production by the Delta(1232)-resonance is typically not the dominant process in Active Galactic Nuclei and Gamma-Ray Bursts, and we show, for arbitrary input spectra, that the number of neutrinos are underestimated by at least a factor of two if they are obtained from the neutral to charged pion ratio. We compare our results for several levels of simplification using isotropic synchrotron and thermal spectra, and we demonstrate that they are sufficiently close to the SOPHIA software.Comment: Treatment of high energy interactions refined, additional black body benchmark added (v2), some references corrected (v3). A Mathematica notebook which illustrates the implementation of one model can be found at http://theorie.physik.uni-wuerzburg.de/~winter/Resources/AstroModel/Sim-B.html . 46 pages, 14 (color) figures, 7 tables. Final version, accepted for publication in Ap

Remote Entanglement between a Single Atom and a Bose-Einstein Condensate

Entanglement between stationary systems at remote locations is a key resource for quantum networks. We report on the experimental generation of remote entanglement between a single atom inside an optical cavity and a Bose-Einstein condensate (BEC). To produce this, a single photon is created in the atom-cavity system, thereby generating atom-photon entanglement. The photon is transported to the BEC and converted into a collective excitation in the BEC, thus establishing matter-matter entanglement. After a variable delay, this entanglement is converted into photon-photon entanglement. The matter-matter entanglement lifetime of 100 $\mu$s exceeds the photon duration by two orders of magnitude. The total fidelity of all concatenated operations is 95%. This hybrid system opens up promising perspectives in the field of quantum information

Do CBCT scans alter surgical treatment plans? Comparison of preoperative surgical diagnosis using panoramic versus cone-beam CT images

Cone beam CT and/or panoramic images are often required for a successful diagnosis in oral and maxillofacial surgery. The aim of this study was to evaluate if 3D diagnostic imaging information had a significant impact on the decision process in six different classes of surgical indications. Material and methods: Records of all patients who had undergone both panoramic X-ray and CBCT imaging due to surgical indications between January 2008 and December 2012 were examined retrospectively. In February 2013, all surgically relevant diagnoses of both conventional panoramic radiographs and CBCT scans were retrieved from the patient's charts. It was recorded whether (1) 3D imaging presented additional surgically relevant information and (2) if the final decision of surgical therapy had been based on 2D or 3D imaging. Results: A total of 253 consecutive patients with both panoramic radiographs and CBCT analysis were eligible for the study. 3D imaging provided significantly more surgically relevant information in cases of implant dentistry, maxillary sinus diagnosis and in oral and maxillofacial traumatology. However, surgical strategies had not been influenced to any significant extent by 3D imaging. Conclusion: Within the limitations of this study it may be concluded that CBCT imaging results in significantly more surgically relevant information in implant dentistry, maxillary sinus diagnosis and in cases of oral and maxillofacial trauma. However, 3D imaging information did not alter significantly the surgical plan that was based on 2D panoramic radiography. Further studies are necessary to define indications for CBCT in detail

Photon-Photon Entanglement with a Single Trapped Atom

An experiment is performed where a single rubidium atom trapped within a high-finesse optical cavity emits two independently triggered entangled photons. The entanglement is mediated by the atom and is characterized both by a Bell inequality violation of S=2.5, as well as full quantum-state tomography, resulting in a fidelity exceeding F=90%. The combination of cavity-QED and trapped atom techniques makes our protocol inherently deterministic - an essential step for the generation of scalable entanglement between the nodes of a distributed quantum network.Comment: 5 pages, 4 figure

High Energy Neutrino Emission and Neutrino Background from Gamma-Ray Bursts in the Internal Shock Model

High energy neutrino emission from GRBs is discussed. In this paper, by using the simulation kit GEANT4, we calculate proton cooling efficiency including pion-multiplicity and proton-inelasticity in photomeson production. First, we estimate the maximum energy of accelerated protons in GRBs. Using the obtained results, neutrino flux from one burst and a diffuse neutrino background are evaluated quantitatively. We also take account of cooling processes of pion and muon, which are crucial for resulting neutrino spectra. We confirm the validity of analytic approximate treatments on GRB fiducial parameter sets, but also find that the effects of multiplicity and high-inelasticity can be important on both proton cooling and resulting spectra in some cases. Finally, assuming that the GRB rate traces the star formation rate, we obtain a diffuse neutrino background spectrum from GRBs for specific parameter sets. We introduce the nonthermal baryon-loading factor, rather than assume that GRBs are main sources of UHECRs. We find that the obtained neutrino background can be comparable with the prediction of Waxman & Bahcall, although our ground in estimation is different from theirs. In this paper, we study on various parameters since there are many parameters in the model. The detection of high energy neutrinos from GRBs will be one of the strong evidences that protons are accelerated to very high energy in GRBs. Furthermore, the observations of a neutrino background has a possibility not only to test the internal shock model of GRBs but also to give us information about parameters in the model and whether GRBs are sources of UHECRs or not.Comment: 14 pages, 17 figures, accepted for publication in PRD, with extended descriptions. Conclusions unchange

An Elementary Quantum Network of Single Atoms in Optical Cavities

Quantum networks are distributed quantum many-body systems with tailored topology and controlled information exchange. They are the backbone of distributed quantum computing architectures and quantum communication. Here we present a prototype of such a quantum network based on single atoms embedded in optical cavities. We show that atom-cavity systems form universal nodes capable of sending, receiving, storing and releasing photonic quantum information. Quantum connectivity between nodes is achieved in the conceptually most fundamental way: by the coherent exchange of a single photon. We demonstrate the faithful transfer of an atomic quantum state and the creation of entanglement between two identical nodes in independent laboratories. The created nonlocal state is manipulated by local qubit rotation. This efficient cavity-based approach to quantum networking is particularly promising as it offers a clear perspective for scalability, thus paving the way towards large-scale quantum networks and their applications.Comment: 8 pages, 5 figure

Propagation of ultra-high energy protons in the nearby universe

We present a new calculation of the propagation of protons with energies above $10^{19}$ eV over distances of up to several hundred Mpc. The calculation is based on a Monte Carlo approach using the event generator SOPHIA for the simulation of hadronic nucleon-photon interactions and a realistic integration of the particle trajectories in a random extragalactic magnetic field. Accounting for the proton scattering in the magnetic field affects noticeably the nucleon energy as a function of the distance to their source and allows us to give realistic predictions on arrival energy, time delay, and arrival angle distributions and correlations as well as secondary particle production spectra.Comment: 12 pages, 9 figures, ReVTeX. Physical Review D, accepte

The GZK horizon and constraints on the cosmic ray source spectrum from observations in the GZK regime

We discuss the GZK horizon of protons and present a method to constrain the injection spectrum of ultrahigh energy cosmic rays (UHECRs) from supposedly identified extragalactic sources. This method can be applied even when only one or two events per source are observed and is based on the analysis of the probability for a given source to populate different energy bins, depending on the actual CR injection spectral index. In particular, we show that for a typical source density of $4\times 10^{-5} Mpc^{-3}$, a data set of 100 events above $6\times 10^{19}$ eV allows one in 97% of all cases to distinguish a source spectrum $dN/dE\propto E^{-1.1}$ from one with $E^{-2.7}$ at 95% confidence level.Comment: v2: 5 pages, 3 figures; shortened, title changed, matches version to be publishe

Defining The Epichromatin Epitope

Epichromatin is identified by immunostaining fixed and permeabilized cells with particular bivalent anti-nucleosome antibodies (mAbs PL2-6 and 1H6). During interphase, epichromatin resides adjacent to the inner nuclear membrane; during mitosis, at the outer surface of mitotic chromosomes. By STED (stimulated emission depletion) microscopy, PL2-6 stained interphase epichromatin is ∼76 nm thick and quite uniform; mitotic epichromatin is more variable in thickness, exhibiting a “wrinkled” surface with an average thickness of ∼78 nm. Co-immunostaining with anti-Ki-67 demonstrates Ki-67 deposition between the PL2-6 “ridges” of mitotic epichromatin. Monovalent papain-derived Fab fragments of PL2-6 yield a strikingly different punctate “chromomeric” immunostaining pattern throughout interphase nuclei and along mitotic chromosome arms. Evidence from electrophoretic mobility shift assay (EMSA) and from analytical ultracentrifugation characterize the Fab/mononucleosome complex, supporting the concept that there are two binding sites per nucleosome. The peptide sequence of the Hv3 region (heavy chain variable region 3) of the PL2-6 antibody binding site strongly resembles other nucleosome acidic patch binding proteins (especially, LANA and CENPC), supporting that the nucleosome acidic patch is included within the epichromatin epitope. It is speculated that the interphase epichromatin epitope is “exposed” with favorable geometric arrangements for binding bivalent PL2-6 at the surface chromatin; whereas, the epitope is “hidden” within internal chromatin. Furthermore, it is suggested that the “exposed” nucleosome surface of mitotic epichromatin may play a role in post-mitotic nuclear envelope reformation