1,120 research outputs found
A Finitary Treatment of the Closed Fragment of Japaridze's Provability Logic
No full textWe study a propositional polymodal provability logic GLP introduced by G. Japaridze. The previous treatments of this logic, due to Japaridze and Ignatiev (see [11, 7]), heavily relied on some non-finitary principles such as transfinite induction up to #0 or reflection principles. In fact, the closed fragment of GLP gives rise to a natural system of ordinal notation for #0 that was used in [1] for a proof-theoretic analysis of Peano arithmetic and for constructing simple combinatorial independent statements. In thi
Long-range spin chirality dimer order in the Heisenberg chain with modulated Dzyaloshinskii-Moriya interactions
No full textThe ground-state phase diagram of a spin S = 1 2 XXZ Heisenberg chain with spatially modulated Dzyaloshinskii-Moriya interaction H= n{J(Sx nSx n+1 +Sy nSy n+1 )+JzSz nSz n+1 +[D0 +(−1)nD1](Sx nSy n+1 −S y nSx n+1 )}is studied using the continuum-limit bosonization approach and extensive density-matrix renormalizationgroupcomputations.Itisshownthattheeffectivecontinuum-limitbosonizedtheoryofthemodelisgivenby the double-frequency sine-Gordon model (DSG) where the frequencies, i.e., the scaling dimensions of the two competing cosine perturbation terms, depend on the effective anisotropy parameter γ∗ =Jz/ J2 +D2 0 +D2 1. Exploring the ground-state properties of the DSG model we show that the zero-temperature phase diagram contains the following four phases: (i) the ferromagnetic phase at γ∗ −1; (ii) the gapless Luttinger-liquid (LL) phase at−1 γ∗ C2 > 1 the gapped composite (C2) phase characterized in addition to the coexisting spin dimerization and alternating chirality patterns, by the presence of LRO antiferromagnetic order. The transition from the LL to the C1 phase at γ∗ C1 belongs to the Berezinskii-Kosterlitz-Thouless universality class, while the transition at γ∗ = γ∗ C2 from C1 to C2 phase is of the Ising type.Fil: Avalishvili, N.. Ilia State University; Georgia. Andronikashvili Institute of Physics; GeorgiaFil: Japaridze, G. I.. Ilia State University; Georgia. Andronikashvili Institute of Physics; GeorgiaFil: Rossini, Gerardo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin
Phase diagram of the spin S = 1/2 extended XY model
No full textThe quantum phase transition in the ground state of the extended spin S=1/2
XY
model has been studied in detail. Using the exact solution of the model the low temperature thermodynamics,
as well as the ground state phase diagram of the model in the presence of applied uniform and/or
staggered magnetic field are discussed
Can We Give it Away? Transferability of Author’s Personal Rights via Contractual Agreement
No full textAuthor’s personal right – a right streaming from the vision that the work is the author’s “spiritual child”, declaring that the former shouldbe the one who always decides the non-economic fate of the latter, was a significant acquirement of last centuries’ legislation. However,international acknowledgement of this right in the Berne Convention and its incorporation in national laws created diversity in its applicationon a country to country basis. One of the most important issues about this right, debatable until today, is the question of its transferability.Civil and common law approaches disagree about the fact whether third persons should be able to acquire an author’s personalright via contractual agreement. The paper will address this issue, discuss the right from historical and comparative perspective, and try tocome up with the answer whether it is transferable by nature, and whether transferability via contractual arrangement should be allowed
Maximal Attainable Boost and Energy of Elementary Particles as a Manifestation of the Limit of Localizability of Elementary Quantum Systems
No full textI discuss an upper bound on the boost and the energy of elementary particles. The limit is derived utilizing the core principle of relativistic quantum mechanics stating that there is a lower bound for localization of an elementary quantum system and the assumption that when the localization scale reaches the Planck length, elementary particles are removed from the S-matrix observables. The limits for the boost and energy, MPlanck/m and MPlanck C 2 ? 8.6 1027 eV,are defined in terms of fundamental constants and the mass of elementary particle and does not involve any dynamic scale. These bounds imply that the cosmic ray flux of any flavor may stretch up to energies of order 1028 GeV and will cut off around this value
Improved Characterization of the Astrophysical Muon-Neutrino Flux with 9.5 Years of IceCube Data
No full textWe present a measurement of the high-energy astrophysical muon�neutrino flux with the IceCube Neutrino Observatory. The measurement uses a high-purity selection of 650k neutrino-induced muon tracks from the northern celestial hemisphere, corresponding to 9.5 yr of experimental data. With respect to previous publications, the measurement is improved by the increased size of the event sample and the extended model testing beyond simple power-law hypotheses. An updated treatment of systematic uncertainties and atmospheric background fluxes has been implemented based on recent models. The best-fit single power-law parameterization for the astrophysical energy spectrum results in a normalization of � f = � n n + - m m + - - -- - @100TeV 1.44 10 GeV cm s sr 0.26 0.25 18 1 2 1 1 and a spectral index g = - + 2.37 SPL 0.09 0.09, constrained in the energy range from 15 TeV to 5 PeV. The model tests include a single power law with a spectral cutoff at high energies, a log-parabola model, several source-class-specific flux predictions from the literature, and a model-independent spectral unfolding. The data are consistent with a single power-law hypothesis, however, spectra with softening above one PeV are statistically more favorable at a twosigma leve
Magnetic phase diagram of the dimerized spin S=1/2 ladder
No full text75.10.Jm Quantized spin models, 75.10.Pq Spin chain models,
Search for High-energy Neutrinos from Ultraluminous Infrared Galaxies with IceCube
No full textUltraluminous infrared galaxies (ULIRGs) have infrared luminosities LIR � 1012Le, making them the most luminous objects in the infrared sky. These dusty objects are generally powered by starbursts with star formation rates that exceed 100 Me yr?1 , possibly combined with a contribution from an active galactic nucleus. Such environments make ULIRGs plausible sources of astrophysical high-energy neutrinos, which can be observed by the IceCube Neutrino Observatory at the South Pole. We present a stacking search for high-energy neutrinos from a representative sample of 75 ULIRGs with redshift z � 0.13 using 7.5 yr of IceCube data. The results are consistent with a background-only observation, yielding upper limits on the neutrino flux from these 75 ULIRGs. For an unbroken E?2.5 power-law spectrum, we report an upper limit on the stacked flux ( ) � 3.24 10 TeV cm s 10 TeV E F= � 90% 14 1 2 1 2.5 n n + - - -- - m m at 90% confidence level. In addition, we constrain the contribution of the ULIRG source population to the observed diffuse astrophysical neutrino flux as well as model predictions
Search for Astrophysical Neutrinos from 1FLE Blazars with IceCube
No full textThe majority of astrophysical neutrinos have undetermined origins. The IceCube Neutrino Observatory has observed astrophysical neutrinos but has not yet identified their sources. Blazars are promising source candidates, but previous searches for neutrino emission from populations of blazars detected in GeV gamma rays have not observed any significant neutrino excess. Recent findings in multimessenger astronomy indicate that high-energy photons, coproduced with high-energy neutrinos, are likely to be absorbed and reemitted at lower energies. Thus, lower-energy photons may be better indicators of TeV�PeV neutrino production. This paper presents the first timeintegrated stacking search for astrophysical neutrino emission from MeV-detected blazars in the first Fermi Large Area Telescope low energy (1FLE) catalog using ten years of IceCube muon�neutrino data. The results of this analysis are found to be consistent with a background-only hypothesis. Assuming an E?2 neutrino spectrum and proportionality between the blazars MeV gamma-ray fluxes and TeV�PeV neutrino flux, the upper limit on the 1FLE blazar energy-scaled neutrino flux is determined to be 1.64 � 10?12 TeV cm?2 s ?1 at 90% confidence level. This upper limit is approximately 1% of IceCube�s diffuse muon�neutrino flux measurement
Searches for Neutrinos from Gamma-Ray Bursts Using the IceCube Neutrino Observatory
No full textGamma-ray bursts (GRBs) are considered as promising sources of ultra-high-energy cosmic rays (UHECRs) due to their large power output. Observing a neutrino flux from GRBs would offer evidence that GRBs are hadronic accelerators of UHECRs. Previous IceCube analyses, which primarily focused on neutrinos arriving in temporal coincidence with the prompt gamma-rays, found no significant neutrino excess. The four analyses presented in this paper extend the region of interest to 14 days before and after the prompt phase, including generic extended time windows and targeted precursor searches. GRBs were selected between 2011 May and 2018 October to align with the data set of candidate muon-neutrino events observed by IceCube. No evidence of correlation between neutrino events and GRBs was found in these analyses. Limits are set to constrain the contribution of the cosmic GRB population to the diffuse astrophysical neutrino flux observed by IceCube. Prompt neutrino emission from GRBs is limited to 1% of the observed diffuse neutrino flux, and emission on timescales up to 104 s is constrained to 24% of the total diffuse flux
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