2,609 research outputs found
Intrinsic measurement errors for the speed of light in vacuum
No full textThe speed of light in vacuum, one of the most important and precisely measured natural constants, is fixed by convention to c = 299 792 458 m s(-1). Advanced theories predict possible deviations from this universal value, or even quantum fluctuations of c. Combining arguments from quantum parameter estimation theory and classical general relativity, we here establish rigorously the existence of lower bounds on the uncertainty to which the speed of light in vacuum can be determined in a given region of space-time, subject to several reasonable restrictions. They provide a novel perspective on the experimental falsifiability of predictions for the quantum fluctuations of space-time.OAIID:RECH_ACHV_DSTSH_NO:T201721132RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A078167CITE_RATE:3.283DEPT_NM:물리·천문학부EMAIL:[email protected]_YN:YN
Probing the Scale Invariance of the Inflationary Power Spectrum in Expanding Quasi-Two-Dimensional Dipolar Condensates
No full textWe consider an analogue de Sitter cosmos in an expanding quasi-two-dimensional Bose-Einstein condensate with dominant dipole-dipole interactions between the atoms or molecules in the ultracold gas. It is demonstrated that a hallmark signature of inflationary cosmology, the scale invariance of the power spectrum of inflaton field correlations, experiences strong modifications when, at the initial stage of expansion, the excitation spectrum displays a roton minimum. Dipolar quantum gases thus furnish a viable laboratory tool to experimentally investigate, with well-defined and controllable initial conditions, whether primordial oscillation spectra deviating from Lorentz invariance at trans-Planckian momenta violate standard predictions of inflationary cosmology.OAIID:RECH_ACHV_DSTSH_NO:T201721131RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A078167CITE_RATE:8.839DEPT_NM:물리·천문학부EMAIL:[email protected]_YN:YN
Amplification of the quantum superposition macroscopicity of a flux qubit by a magnetized Bose gas
No full textWe calculate a measure of superposition macroscopicity M for a superposition of screening current states in a superconducting flux qubit (SFQ), by relating M to the action of an instanton trajectory connecting the potential wells of the flux qubit. When a magnetized Bose-Einstein condensed (BEC) gas containing N-B similar to O (10(6)) atoms is brought into a O(1) mu m proximity of the flux qubit in an experimentally realistic geometry, we demonstrate the appearance of a twofold to fivefold amplification of M over the bare value without the BEC, by calculating the instanton trajectory action from the microscopically derived effective flux Lagrangian of a hybrid quantum system composed of the flux qubit and a spin-F atomic Bose gas. Exploiting the connection between M and the maximal metrological usefulness of a multimode superposition state, we show that amplification of M in the ground state of the hybrid system is equivalent to a decrease in the quantum Cramer-Rao bound for estimation of an externally applied flux. Our result therefore demonstrates the increased usefulness of the BEC-SFQ hybrid system as a sensor of ultraweak magnetic fields below the standard quantum limit.N
Quantum sine-Gordon dynamics on analogue curved spacetime in a weakly imperfect scalar Bose gas
No full textUsing the coherent state functional integral expression of the partition function, we show that the sine-Gordon model on an analogue curved spacetime arises as the effective quantum field theory for phase fluctuations of a weakly imperfect Bose gas on an incompressible background superfluid flow when these fluctuations are restricted to a subspace of the single-particle Hilbert space. We consider bipartitions of the single-particle Hilbert space relevant to experiments on ultracold bosonic atomic or molecular gases, including, e.g., restriction to high-or low-energy sectors of the dynamics and spatial bipartition corresponding to tunnel-coupled planar Bose gases. By assuming full unitary quantum control in the low-energy subspace of a trapped gas, we show that (1) appropriately tuning the particle number statistics of the lowest-energy mode partially decouples the low-and high-energy sectors, allowing any low-energy single-particle wave function to define a background for sine-Gordon dynamics on curved spacetime and (2) macroscopic occupation of a quantum superposition of two states of the lowest two modes produces an analogue curved spacetime depending on two background flows, with respective weights continuously dependent on the corresponding weights of the superposed quantum states.N
The Network of Innovators in Jena: An Application of Social Network Analysis
No full textWe apply social network analysis methods to describe the evolution of the innovator network of Jena, Germany in the period from 1995 to 2001. We find this evolution to be directed towards an increasing focus on core competencies of the local innovation system. Further we analyze the network resulting from R&D cooperations and explain - by means of network regression techniques - that the job mobility of scientists and the technological overlap between the actors, rather than past cooperations, can best predict the resulting structure. We also observe an increasing importance of the university while the former "Kombinate" begin to lose their prominent role.Innovator Networks, Network Regression, Local Innovation Systems, R+D Cooperation, Research University
„More and More“ oder Kannibalisierung? Eine empirische Analyse der Nutzungskonvergenz von Nachrichten- und Unterhaltungsangeboten in TV und WWW
No full textTrepte S, Baumann E. „More and More“ oder Kannibalisierung? Eine empirische Analyse der Nutzungskonvergenz von Nachrichten- und Unterhaltungsangeboten in TV und WWW. In: Hasebrink U, Mikos L, Prommer E, eds. Mediennutzung und Medienrezeption in konvergierenden Medienumgebungen. München: R. Fischer; 2004: 173-197
Yxilon – a Modular Open-Source Statistical Programming Language
No full textStatistical research has always been at the edge of available computing power. Huge datasets, e.g in DataMining or Quantitative Finance, and computationally intensive techniques, e.g. bootstrap methods, always require a little bit more computing power than is currently available. But the most popular statistical programming language R, as well as statistical programming languages like S or XploRe, are interpreted which makes them slow in computing intensive areas. The common solution is to implement these routines in low-level programming languages like C/C++ or Fortran and subsequently integrate them as dynamic linked libraries (DLL) or shared object libraries (SO) in the statistical programming language.statistical programming language, XploRe, Yxilon, Java, dynamic linked libraries, shared object libraries
Terrorism and jihad in Indonesia: Questions and possible ways forward
No full textWe critically examine the three papers on terrorism and jihad in Indonesia contained in this issue. First, we argue that thorough discussion and definition of key terms (including religious violence and jihad) would have led to a much stronger framework for understanding the voices of the activists and their supporters. Second, the authors could have engaged more systematically with the international literature on intergroup relations and conflict to discuss how psychological and social processes of radicalization are similar or different in the Indonesian context. Third, we highlight methodological and ethical shortcomings in the three papers that call into question a number of the conclusions drawn by the authors. We outline future research questions and provide suggestions to strengthen this important line of research. © 2013 Wiley Publishing Asia Pty Ltd with the Asian Association of Social Psychology and the Japanese Group Dynamics Association.Altemeyer B, 1998, ADV EXP SOC PSYCHOL, V30, P47; Baltes P. B., 2006, HDB CHILD PSYCHOL, V1, P569, DOI DOI 10.1002-9780470147658.CHPSY0111; Fischer R, 2008, BASIC APPL SOC PSYCH, V30, P167, DOI 10.1080-01973530802209202; Fischer R, 2012, JUSTICE AND CONFLICTS: THEORETICAL AND EMPIRICAL CONTRIBUTIONS, P345, DOI 10.1007-978-3-642-19035-3_21; Ginges J, 2011, AM PSYCHOL, V66, P507, DOI 10.1037-a0024715; International Crisis Group, 2012, 228 INT CRIS GROUP; Khomeini R., 2003, GREATEST JIHAD COMBA; Klandermans B, 2002, AM BEHAV SCI, V45, P887, DOI 10.1177-0002764202045005009; Klein O, 2007, PERS SOC PSYCHOL REV, V11, P28, DOI 10.1177-1088868306294588; Milla M. N., 2013, ASIAN J SOC PSYCHOL, V16, P88; Muluk H., 2013, ASIAN J SOC PSYCHOL, V16, P97; Noricks D., 2009, SOCIAL SCI COUNTERTE, P299; Putra I. E., 2013, ASIAN J SOC PSYCHOL, V16, P79; Qutb S., 1982, MILESTONES PATH; Ramadan T., 2008, RADICAL REFORM ISLAM; Ramadan T., 2009, ISLAM W CHALLENGES M; Reicher S, 2004, POLIT PSYCHOL, V25, P921, DOI 10.1111-j.1467-9221.2004.00403.x; Said E., 1981, COVERING ISLAM MEDIA; Sidanius J., 2001, SOCIAL DOMINANCE INT; Simon B, 1998, J PERS SOC PSYCHOL, V74, P646, DOI 10.1037--0022-3514.74.3.646; Simon B, 2001, AM PSYCHOL, V56, P319, DOI 10.1037--0003-066X.56.4.319; Stephan W.F., 2000, CLAR S APPL SOC PSYC, P23; Tetlock PE, 2003, TRENDS COGN SCI, V7, P320, DOI 10.1016-S1364-6613(03)00135-9; Tyler Tom R., 1997, SOCIAL JUSTICE DIVER; van de Vijver F. J. R., 1997, METHODS DATA ANAL CR; van Zomeren M, 2008, PSYCHOL BULL, V134, P504, DOI 10.1037-0033-2909.134.4.50411
2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopenten – Synthese und Reaktionen
No full textN,N'-Di-tert-butyl-1,4-diaza-1,3-butadiene reacts with elemental lithium under reduction to give a dilitbium salt, which forms with fluorosilanes the diazasilacyclopentenes 1-4; (HCNCMe3)2SiFR, R = F (1), Me (2), Me3C (3), N(CMe3)SiMe3 (4). As by-product in the synthesis of 1, the tert-butyl-aminomethylene-tert-butyliminomethine substituted compound 5 was isolated, R = N(CMe3)+CH2-CH = NCMe3. 5 is formed in the reaction of 1 with the monolithium salt of the 1,4-diaza-1,3-butadiene in an enamine-imine-tautomerism. 1 reacts with lithium amides to give (HCNCMe3)(2)SiFNHR, 6-12, R = H (6), Me (7), Me2CH (8), Me3C (9), H5C6 (10), 2,6-Me2C6H3 (11), 2,6-(Me2CH)(2)C6H3 (12). The reaction of 12 with LiNH-2.6-(Me2CH)(2)C6H3 leads to the formation of (HCNCMe3)(2)Si(NHR)(2), (13). In the presence of n-BuLi, 12 forms a lithium salt which looses LiF in boiling toluene. Lithiated 12 adds this LiF and generates a spirocychc tetramer with a central eight-membered LiF-ring (14), [(HCNCMe3)(2)Si(FLiFLiNR)](4), R = 2,6-(Me2CH)(2)C6H3. ClSiMe3 reacts with lithiated 12 to yield the substitution product (HCNCMe3)(2)SiFN(SiMe3) R, (15). The crystal structures of 1, 5, 6, 9, 11, 13, 14 are reported
Erratum to Fischer et al. "Inhibitor development in nonsevere haemophilia across Europe" (Thromb Haemost 2015; 114: 670-675).
No full text[This corrects the article DOI: 10.1160/TH14-12-1044.]. In the Original Article by Fischer et al. "Inhibitor development in non- severe haemophilia across Europe" (Thromb Haemost 2015; 114: 670-675), the author R. Hollingsworth was omitted by mistake. Please find the corrected list of authors here: Fischer K, Iorio A, Lassila R, Peyvandi F, Calizzani G, Gatt A, Lambert T, Windyga J, Gilman EA, Hollingsworth R, Makris M, on behalf of the EUHASS participants
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