294,425 research outputs found
Best possible densities of Dickson m-tuples, as a consequence of Zhang-Maynard-Tao
We determine for what proportion of integers one now knows that there are
infinitely many prime pairs as a consequence of the Zhang-Maynard-Tao
theorem. We consider the natural generalization of this to -tuples of
integers, and we determine the limit of what can be deduced assuming only the
Zhang-Maynard-Tao theorem.Comment: 9 pages. Final version. Some minor changes, Analytic Number Theory -
In Honor of Helmut Maier's 60th Birthday, Springer, 201
Problems of Clustering of Radiogalaxies
We present the preliminary analysis of clustering of a sample of 1157
radio-identified galaxies from Machalski & Condon (1999). We found that for
separations Mpc their redshift space autocorrelation function
can be approximated by the power law with the correlation length Mpc and slope . The correlation length for
radiogalaxies is found to be lower and the slope steeper than the corresponding
parameters of the control sample of optically observed galaxies. Analysis the
projected correlation function displays possible differences in the
clustering properties between active galactic nuclei (AGN) and starburst (SB)
galaxies.Comment: Submitted: Proceedings of IAUS 290 "Feeding Compact Objects:
Accretion on All Scales", C. M. Zhang, T. Belloni, M. Mendez & S. N. Zhang
(eds.
Exact Analysis of Level-Crossing Statistics for (d+1)-Dimensional Fluctuating Surfaces
We carry out an exact analysis of the average frequency
in the direction of positive-slope crossing of a given level
such that, , of growing surfaces in spatial
dimension . Here, is the surface height at time , and
is its mean value. We analyze the problem when the surface growth
dynamics is governed by the Kardar-Parisi-Zhang (KPZ) equation without surface
tension, in the time regime prior to appearance of cusp singularities (sharp
valleys), as well as in the random deposition (RD) model. The total number
of such level-crossings with positive slope in all the directions is then
shown to scale with time as for both the KPZ equation and the RD
model.Comment: 22 pages, 3 figure
On Real Solutions of the Equation Φ\u3csup\u3e\u3cem\u3et\u3c/em\u3e\u3c/sup\u3e (\u3cem\u3eA\u3c/em\u3e) = 1/\u3cem\u3en\u3c/em\u3e J\u3csub\u3e\u3cem\u3en\u3c/em\u3e\u3c/sub\u3e
For a class of n × n-matrices, we get related real solutions to the matrix equation Φt (A) = 1/n Jn by generalizing the approach of and applying the results of Zhang, Yang, and Cao [SIAM J. Matrix Anal. Appl., 21 (1999), pp. 642–645]. These solutions contain not only those obtained by Zhang, Yang, and Cao but also some which are neither diagonally nor permutation equivalent to those obtained by Zhang, Yang, and Cao. Therefore, the open problem proposed by Zhang, Yang, and Cao in the cited paper is solved
Quantum Dynamical Echoes in the Spin 'Diffusion' in Mesoscopic Systems
The evolution of local spin polarization in finite systems involves
interference phenomena that give rise to {\bf quantum dynamical echoes }and
non-ergodic behavior. We predict the conditions to observe these echoes by
exploiting the NMR sequences devised by Zhang et al. [Phys. Rev. Lett. {\bf %
69}, 2149 (1992)], which uses a rare C as {\bf local probe }for a
dipolar coupled H spin system. The non-ideality of this probe when testing
mesoscopic systems is carefully analyzed revealing the origin of various
striking experimental features.Comment: 4 pages, Revtex, 3 Figures available upon reques
Theory of Four-dimensional Fractional Quantum Hall States
We propose a pseudo-potential Hamiltonian for the Zhang-Hu's generalized
fractional quantum Hall states to be the exact and unique ground states.
Analogously to Laughlin's quasi-hole (quasi-particle), the excitations in the
generalized fractional quantum Hall states are extended objects. They are
vortex-like excitations with fractional charges in the total
configuration space CP. The density correlation function of the Zhang-Hu
states indicates that they are incompressible liquid.Comment: 4 page
The price Asian venture capitalists pay to work in Silicon Valley
They pay higher valuations due to their lower social status rather than social network disadvantages, write Jing Zhang, Poh-Kam Wong and Yuen-Ping H
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