1,928 research outputs found
The cosmic ray differential diurnal variation dependences on the zenith angle and the geomagnetic disturbance
Simultaneous and continuous muon measurements in two opposite azimuthal directions under equal zenith angles demonstrated the importance of this method for cosmic ray diurnal variation investigations. Lately these measurements were extended by means of improved telescopes. The obtained cosmic ray diurnal variations were presented as intensity differential curves. Theoretical investigations connected the properties of these curves with some interplanetary spece parameters. The harmonics of these curves were interpreted physically. Some order difference curves were introduced. In earlier works some dependences between the parameters characterizing the first and the second harmonics of the differential intensity curves and the geomagnetic activity were found. Then all measurements were carried out under only one zenith angle. The results of investigations of similar dependences using data of simultaneous measurements under three different zenith angles are presented
A Unified Conformal Field Theory Description of Paired Quantum Hall States
The wave functions of the Haldane-Rezayi paired Hall state have been
previously described by a non-unitary conformal field theory with central
charge c=-2. Moreover, a relation with the c=1 unitary Weyl fermion has been
suggested. We construct the complete unitary theory and show that it
consistently describes the edge excitations of the Haldane-Rezayi state.
Actually, we show that the unitary (c=1) and non-unitary (c=-2) theories are
related by a local map between the two sets of fields and by a suitable change
of conjugation. The unitary theory of the Haldane-Rezayi state is found to be
the same as that of the 331 paired Hall state. Furthermore, the analysis of
modular invariant partition functions shows that no alternative unitary
descriptions are possible for the Haldane-Rezayi state within the class of
rational conformal field theories with abelian current algebra. Finally, the
known c=3/2 conformal theory of the Pfaffian state is also obtained from the
331 theory by a reduction of degrees of freedom which can be physically
realized in the double-layer Hall systems.Comment: Latex, 42 pages, 2 figures, 3 tables; minor corrections to text and
reference
Computational equivalence of the two inequivalent spinor representations of the braid group in the Ising topological quantum computer
We demonstrate that the two inequivalent spinor representations of the braid
group \B_{2n+2}, describing the exchanges of 2n+2 non-Abelian Ising anyons in
the Pfaffian topological quantum computer, are equivalent from computational
point of view, i.e., the sets of topologically protected quantum gates that
could be implemented in both cases by braiding exactly coincide. We give the
explicit matrices generating almost all braidings in the spinor representations
of the 2n+2 Ising anyons, as well as important recurrence relations. Our
detailed analysis allows us to understand better the physical difference
between the two inequivalent representations and to propose a process that
could determine the type of representation for any concrete physical
realization of the Pfaffian quantum computer.Comment: 9 pages, 2 figures, published versio
The influence of massive stars in the interstellar medium of IC 1613: the supernova remnant S8 and the nebula S3 associated with a WO star
We present a detailed kinematical analysis of two selected nebulae in the
Local Group irregular galaxy IC 1613. The nebulae are: S8, the only known
supernova remnant in this galaxy, and S3, a Wolf-Rayet nebula associated with
the only WO star in this galaxy. For S8, we have obtained and analyzed its
radial velocity field, where we found complex profiles which can be fitted by
several velocity components. These profiles also show the presence of high
velocity, low density gas. From this, we have obtained the expansion velocity,
estimated the preshock density and calculated the basic kinematical parameters
of this SNR. We suggest that in S8 we are seing a SNR partially hidden by dust.
This suggestion comes from the fact that the SNR is located between two
superbubbles where a ridge of obscured material unveils the existence of dust.
Moreover, we show that this hypothesis prevails when energetic arguments are
taken into account. In the case of S3, this nebula shows bipolar structure. By
means of its kinematics, we have analyzed its two lobes, the ``waist'', as well
as its relation with the nearest superbubbles. For the first time we are able
to see closed the NW lobe, showing a clover leaf shape. This fact allows a
better quantitative knowledge of the nebula as a whole. Furthermore, we found
evidence of an expansion motion in the NW lobe. In the light of our results, we
can express that these nebulae are the product of very massive stellar
evolution. It is surprising the influence these stars still have in shaping
their surrounding gas, and on the energy liberation towards the interstellar
medium of this galaxy.Comment: Accepted for publication in the Astronomical Journal, July issue. 11
pages, 12 figures. High resolution figures can be found at
http://www.inaoep.mx/~mago/PAPERS/AJ
Chiral persistent currents and magnetic susceptibilities in the parafermion quantum Hall states in the second Landau level with Aharonov-Bohm flux
Using the effective conformal field theory for the quantum Hall edge states
we propose a compact and convenient scheme for the computation of the periods,
amplitudes and temperature behavior of the chiral persistent currents and the
magnetic susceptibilities in the mesoscopic disk version of the Z_k parafermion
quantum Hall states in the second Landau level. Our numerical calculations show
that the persistent currents are periodic in the Aharonov-Bohm flux with period
exactly one flux quantum and have a diamagnetic nature. In the high-temperature
regime their amplitudes decay exponentially with increasing the temperature and
the corresponding exponents are universal characteristics of non-Fermi liquids.
Our theoretical results for these exponents are in perfect agreement with those
extracted from the numerical data and demonstrate that there is in general a
non-trivial contribution coming from the neutral sector. We emphasize the
crucial role of the non-holomorphic factors, first proposed by Cappelli and
Zemba in the context of the conformal field theory partition functions for the
quantum Hall states, which ensure the invariance of the annulus partition
function under the Laughlin spectral flow.Comment: 14 pages, RevTeX4, 7 figures (eps
DeepX: A Software Accelerator for Low-Power Deep Learning Inference on Mobile Devices
© 2016 IEEE. Breakthroughs from the field of deep learning are radically changing how sensor data are interpreted to extract the high-level information needed by mobile apps. It is critical that the gains in inference accuracy that deep models afford become embedded in future generations of mobile apps. In this work, we present the design and implementation of DeepX, a software accelerator for deep learning execution. DeepX signif- icantly lowers the device resources (viz. memory, computation, energy) required by deep learning that currently act as a severe bottleneck to mobile adoption. The foundation of DeepX is a pair of resource control algorithms, designed for the inference stage of deep learning, that: (1) decompose monolithic deep model network architectures into unit- blocks of various types, that are then more efficiently executed by heterogeneous local device processors (e.g., GPUs, CPUs); and (2), perform principled resource scaling that adjusts the architecture of deep models to shape the overhead each unit-blocks introduces. Experiments show, DeepX can allow even large-scale deep learning models to execute efficently on modern mobile processors and significantly outperform existing solutions, such as cloud-based offloading
Gradient-free quantum optimization on NISQ devices
Variational Quantum Eigensolvers (VQEs) have recently attracted considerable
attention. Yet, in practice, they still suffer from the efforts for estimating
cost function gradients for large parameter sets or resource-demanding
reinforcement strategies. Here, we therefore consider recent advances in
weight-agnostic learning and propose a strategy that addresses the trade-off
between finding appropriate circuit architectures and parameter tuning. We
investigate the use of NEAT-inspired algorithms which evaluate circuits via
genetic competition and thus circumvent issues due to exceeding numbers of
parameters. Our methods are tested both via simulation and on real quantum
hardware and are used to solve the transverse Ising Hamiltonian and the
Sherrington-Kirkpatrick spin model.Comment: 13 pages, 6 figures, comments welcome
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