4,997 research outputs found
Phonon emission and absorption in the fractional quantum Hall effect
We investigate the time dependent thermal relaxation of a two-dimensional
electron system in the fractional quantum Hall regime where ballistic phonons
are used to heat up the system to a non-equilibrium temperature. The thermal
relaxation of a 2DES at can be described in terms of a broad band
emission of phonons, with a temperature dependence proportional to . In
contrast, the relaxation at fractional filling is characterized by
phonon emission around a single energy, the magneto-roton gap. This leads to a
strongly reduced energy relaxation rate compared to with only a weak
temperature dependence for temperatures 150 mK 400 mK.Comment: 4 pages, 3 figures; 14th International Conference on High Magnetic
Fields in Semiconductor Physics, September 24-29, 2000, Matsue, Japa
Low-Energy Charge-Density Excitations in MgB: Striking Interplay between Single-Particle and Collective Behavior for Large Momenta
A sharp feature in the charge-density excitation spectra of single-crystal
MgB, displaying a remarkable cosine-like, periodic energy dispersion with
momentum transfer () along the -axis, has been observed for the first
time by high-resolution non-resonant inelastic x-ray scattering (NIXS).
Time-dependent density-functional theory calculations show that the physics
underlying the NIXS data is strong coupling between single-particle and
collective degrees of freedom, mediated by large crystal local-field effects.
As a result, the small- collective mode residing in the single-particle
excitation gap of the B bands reappears periodically in higher Brillouin
zones. The NIXS data thus embody a novel signature of the layered electronic
structure of MgB.Comment: 5 pages, 4 figures, submitted to PR
Development of neural network-based electronic nose for herbs recognition
The ability to classify distinctive odor pattern for aromatic plants species provides significant impact in food industry especially for herbs. Each herbs species has a unique physicochemical and a distinctive odors. This project emphasizes on the techniques of artificial intelligence (AI) to distinguish distinctive odor pattern for herbs. Neural Network method has been exploited for the classification and optimization of various odor patterns. Based on AI techniques, Neural Network-based electronic nose system for herbs recognition has been developed. The system consist multi-sensor gas array which detects gas through an increase in electrical conductivity when reducing gases are absorbed on the sensor's surface. The output from individual sensors are collectively assembled and integrated to produce a distinct digital response pattern. A selected sensor array shows its relationship with the aroma of the herbs through the GC-MS test. By using five samples of herbs, the E-nose system has been tested with five different types of sensor. From the results, E-nose system with five sensors has the highest capability in classifying herbs sample. Accuracy in classifying the correct herbs increases with the number of sensors used. This investigation demonstrates that the neural network-based electronic nose technique promises a successful technique in the ability to classify distinctive odor pattern for aromatic herbs species
Gradient flows and instantons at a Lifshitz point
I provide a broad framework to embed gradient flow equations in
non-relativistic field theory models that exhibit anisotropic scaling. The
prime example is the heat equation arising from a Lifshitz scalar field theory;
other examples include the Allen-Cahn equation that models the evolution of
phase boundaries. Then, I review recent results reported in arXiv:1002.0062
describing instantons of Horava-Lifshitz gravity as eternal solutions of
certain geometric flow equations on 3-manifolds. These instanton solutions are
in general chiral when the anisotropic scaling exponent is z=3. Some general
connections with the Onsager-Machlup theory of non-equilibrium processes are
also briefly discussed in this context. Thus, theories of Lifshitz type in d+1
dimensions can be used as off-shell toy models for dynamical vacuum selection
of relativistic field theories in d dimensions.Comment: 19 pages, 1 figure, contribution to conference proceedings (NEB14);
minor typos corrected in v
Bendamustine: Safety and Efficacy in the Management of Indolent Non-Hodgkins Lymphoma
Bendamustine (Treanda, Ribomustin) was recently approved by the US Food and Drug Administration (FDA) for treatment of patients with rituximab refractory indolent lymphoma and is expected to turn into a frontline therapy option for indolent lymphoma. This compound with amphoteric properties was designed in the former Germany Democratic Republic in 1960s and re-discovered in 1990s with multiple successive well-designed studies. Bendamustine possesses a unique mechanism of action with potential antimetabolite properties, and only partial cross-resistance with other alkylators. Used in combination with rituximab in vitro, bendamustine shows synergistic effects against various leukemia and lymphoma cell lines. In clinical studies, bendamustine plus rituximab is highly effective in patients with relapsed-refractory indolent lymphoma, inducing remissions in 90% or more and a median progression-free survival of 23–24 months. The optimal dosing and schedule of bendamustine administration is largely undecided and varies among studies. Results of ongoing trials and dose-finding studies will help to further help ascertain the optimal place of bendamustine in the management of indolent NHL
All stationary axi-symmetric local solutions of topologically massive gravity
We classify all stationary axi-symmetric solutions of topologically massive
gravity into Einstein, Schr\"odinger, warped and generic solutions. We
construct explicitly all local solutions in the first three sectors and present
an algorithm for the numerical construction of all local solutions in the
generic sector. The only input for this algorithm is the value of one constant
of motion if the solution has an analytic centre, and three constants of motion
otherwise. We present several examples, including soliton solutions that
asymptote to warped AdS.Comment: 42 pages, 9 figures. v2: Changed potentially confusing labelling of
one sector, added references. v3: Minor changes, matches published versio
Critical solutions in topologically gauged N=8 CFTs in three dimensions
In this paper we discuss some special (critical) background solutions that
arise in topological gauged three-dimensional CFTs with SO(N)
gauge group. These solutions solve the TMG equations (containing the parameters
and ) for a certain set of values of obtained by varying the
number of scalar fields with a VEV. Apart from Minkowski, chiral round
and null-warped (or Schr\"odinger(z=2)) we identify also a more exotic
solution recently found in by Ertl, Grumiller and Johansson. We also
discuss the spectrum, symmetry breaking pattern and the supermultiplet
structure in the various backgrounds and argue that some properties are due to
their common origin in a conformal phase. Some of the scalar fields, including
all higgsed ones, turn out to satisfy three-dimensional singleton field
equations. Finally, we note that topologically gauged ABJ(M)
theories have a similar, but more restricted, set of background solutions.Comment: 34 pages, v2: minor corrections, note about a new solution added in
final section, v3: two footnotes adde
Statistical properties of stochastic 2D Navier-Stokes equations from linear models
A new approach to the old-standing problem of the anomaly of the scaling
exponents of nonlinear models of turbulence has been proposed and tested
through numerical simulations. This is achieved by constructing, for any given
nonlinear model, a linear model of passive advection of an auxiliary field
whose anomalous scaling exponents are the same as the scaling exponents of the
nonlinear problem. In this paper, we investigate this conjecture for the 2D
Navier-Stokes equations driven by an additive noise. In order to check this
conjecture, we analyze the coupled system Navier-Stokes/linear advection system
in the unknowns . We introduce a parameter which gives a
system ; this system is studied for any
proving its well posedness and the uniqueness of its invariant measure
.
The key point is that for any the fields and
have the same scaling exponents, by assuming universality of the
scaling exponents to the force. In order to prove the same for the original
fields and , we investigate the limit as , proving that
weakly converges to , where is the only invariant
measure for the joint system for when .Comment: 23 pages; improved versio
A compactness theorem for complete Ricci shrinkers
We prove precompactness in an orbifold Cheeger-Gromov sense of complete
gradient Ricci shrinkers with a lower bound on their entropy and a local
integral Riemann bound. We do not need any pointwise curvature assumptions,
volume or diameter bounds. In dimension four, under a technical assumption, we
can replace the local integral Riemann bound by an upper bound for the Euler
characteristic. The proof relies on a Gauss-Bonnet with cutoff argument.Comment: 28 pages, final version, to appear in GAF
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