5,417 research outputs found
Entanglement Entropy in the Two-Dimensional Random Transverse Field Ising Model
The scaling behavior of the entanglement entropy in the two-dimensional
random transverse field Ising model is studied numerically through the strong
disordered renormalization group method. We find that the leading term of the
entanglement entropy always scales linearly with the block size. However,
besides this \emph{area law} contribution, we find a subleading logarithmic
correction at the quantum critical point. This correction is discussed from the
point of view of an underlying percolation transition, both at finite and at
zero temperature.Comment: 4.3 pages, 4 figure
Analytic treatment of geodesics in five-dimensional Myers-Perry space--times
We present the complete set of analytical solutions of the geodesic equation
in the five-dimensional Myers-Perry space-time with equal rotation parameter in
terms of the Weierstra{\ss}' elliptic and Weierstra{\ss}' zeta and sigma
functions. We study the underlying polynomials in the polar and radial
equations which depend on the parameters of the metric and conserved quantities
of a test particle and characterize the motion by their zeros. We exemplify the
efficiency of the analytical method on the orbits of test particles.Comment: 15 pages, 7 figures, to be published in PRD. Version with improved
reference
Study of three-nucleon dynamics in the dp breakup collisions using the Wasa detector
An experiment to investigate the ^{1}H(d,pp)n breakup reaction using a deuteron beam of 300, 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Jülich. As a first step, the data collected at the beam energy of 340 MeV are analysed, with a focus on the proton–proton coincidences registered in the Forward Detector. Elastically scattered deuterons are used for precise determination of the luminosity. The main steps of the analysis, including energy calibration, particle identification (PID) and efficiency studies, and their impact on the final accuracy of the result, are discussed
Study of three-nucleon dynamics in the dp breakup collisions using the Wasa detector
An experiment to investigate the ^{1}H(d,pp)n breakup reaction using a deuteron beam of 300, 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Jülich. As a first step, the data collected at the beam energy of 340 MeV are analysed, with a focus on the proton–proton coincidences registered in the Forward Detector. Elastically scattered deuterons are used for precise determination of the luminosity. The main steps of the analysis, including energy calibration, particle identification (PID) and efficiency studies, and their impact on the final accuracy of the result, are discussed
Conductivity and Atomic Structure of Isolated Multiwalled Carbon Nanotubes
We report associated high resolution transmission electron microscopy (HRTEM)
and transport measurements on a series of isolated multiwalled carbon
nanotubes. HRTEM observations, by revealing relevant structural features of the
tubes, shed some light on the variety of observed transport behaviors, from
semiconducting to quasi-metallic type. Non Ohmic behavior is observed for
certain samples which exhibit "bamboo like" structural defects. The resistance
of the most conducting sample, measured down to 20 mK, exhibits a pronounced
maximum at 0.6 K and strong positive magnetoresistance.Comment: 4 pages, 4 eps figure
Deuteron-deuteron collision at 160 MeV
The experiment was carried out using BINA detector at KVI in Groningen. For
the first time an extensive data analysis of the data collected in back part of
the detector is presented, where a clusterization method is utilized for
angular and energy information. We also present differential cross-sections for
the (dddpn) breakup reaction within \textit{dp} quasi-free
scattering limit and their comparison with first calculations based on Single
Scattering Approximation (SSA) approach.Comment: 6 pages, 4 figures, presented at Jagiellonian Symposium 2015 in
Krakow, PhD wor
Experimental study of three-nucleon dynamics in proton-deuteron breakup reaction
Proton–deuteron breakup reaction can serve as a tool to test stateof-
the-art descriptions of nuclear interactions. At intermediate energies,
below the threshold for pion production, comparison of the data with exact
theoretical calculations is possible and subtle effects of the dynamics beyond
the pairwise nucleon–nucleon interaction, namely the three-nucleon force
(3NF), are significant. Beside 3NF, Coulomb interaction or relativistic
effects are also important to precisely describe the differential cross section
of the breakup reaction. The data analysis and preliminary results of the
measurement of proton-induced deuteron breakup at the Cyclotron Center
Bronowice, Institute of Nuclear Physics, Polish Academy of Sciences in
Kraków are presented
The disordered-free-moment phase: a low-field disordered state in spin-gap antiferromagnets with site dilution
Site dilution of spin-gapped antiferromagnets leads to localized free
moments, which can order antiferromagnetically in two and higher dimensions.
Here we show how a weak magnetic field drives this order-by-disorder state into
a novel disordered-free-moment phase, characterized by the formation of local
singlets between neighboring moments and by localized moments aligned
antiparallel to the field. This disordered phase is characterized by the
absence of a gap, as it is the case in a Bose glass. The associated
field-driven quantum phase transition is consistent with the universality of a
superfluid-to-Bose-glass transition. The robustness of the
disordered-free-moment phase and its prominent features, in particular a series
of pseudo-plateaus in the magnetization curve, makes it accessible and relevant
to experiments.Comment: 4 pages, 4 figure
Measuring nonclassicality of bosonic field quantum states via operator ordering sensitivity
We introduce a new distance-based measure for the nonclassicality of the
states of a bosonic field, which outperforms the existing such measures in
several ways. We define for that purpose the operator ordering sensitivity of
the state which evaluates the sensitivity to operator ordering of the Renyi
entropy of its quasi-probabilities and which measures the oscillations in its
Wigner function. Through a sharp control on the operator ordering sensitivity
of classical states we obtain a precise geometric image of their location in
the density matrix space allowing us to introduce a distance-based measure of
nonclassicality. We analyse the link between this nonclassicality measure and a
recently introduced quantum macroscopicity measure, showing how the two notions
are distinct
Towards a Macroscopic Modelling of the Complexity in Traffic Flow
We present a macroscopic traffic flow model that extends existing fluid-like
models by an additional term containing the second derivative of the safe
velocity. Two qualitatively different shapes of the safe velocity are explored:
a conventional Fermi-type function and a function exhibiting a plateau at
intermediate densities. The suggested model shows an extremely rich dynamical
behaviour and shows many features found in real-world traffic data.Comment: submitted to Phys. Rev.
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