arXiv subjects

Fei Hu

Publications and source records attributed to Fei Hu.

60 records · Page 4Linked to original sources

arXiv2015

Criteria for the existence of equivariant fibrations on algebraic surfaces and hyperkähler manifolds and equality of automorphisms up to powers - a dynamical viewpoint

Let $X$ be a projective surface or a hyperkähler manifold and $G \le Aut(X)$. We give a necessary and sufficient condition for the existence of a non-trivial $G$-equivariant fibration on $X$. We also show that two automorphisms $g_i$ of positive entropy and polarized by the same nef divisor are the same up to powers, provided that either $X$ is not an abelian surface or the $g_i$ share at least one common periodic point. The surface case is known among experts, but we treat this case together with the hyperkähler case using the same language of hyperbolic lattice and following Ratcliffe or Oguiso. This arXiv version contains proofs omitted in the print version.

math.AG↗

arXiv2015

Spatiotemporal Intermittency on the Growing Surface of Coupled Sandpiles

The surface of conservative coupled sandpiles in the self-organized cooperative critical state is found to exhibit intermittency in both time and space. The spatiotemporal intermittent structure is also found to be a multifractal. The probability density of sand grain heights on the surface is an asymptotic power law but with an exponential cut-off. The power spectra of the time series of sand grain heights show a diversity of low-frequency components over different sites on the surface and also over different ensemble samples. This means that the long-term prediction according to the nearby observations and the history experiences is very difficult in the world of coupled sandpiles. Unlike the low-frequency spectra, the high-frequency spectra seem to obey a universal $f^{-2}$ law.

nlin.AO↗

arXiv2014

Ampleness of canonical divisors of hyperbolic normal projective varieties

Let X be a projective variety which is algebraic Lang hyperbolic. We show that Lang's conjecture holds (one direction only): X and all its subvarieties are of general type and the canonical divisor K_X is ample at smooth points and Kawamata log terminal points of X, provided that K_X is Q-Cartier, no Calabi-Yau variety is algebraic Lang hyperbolic and a weak abundance conjecture holds.

math.AG↗

arXiv2013

Self-Organized Cooperative Criticality in Coupled Complex Systems

We show that the coupled complex systems can evolve into a new kind of self-organized critical state where each subsystem is not critical, however, they cooperate to be critical. This criticality is different from the classical BTW criticality where the single system itself evolves into a critical state. We also find that the outflows can be accumulated in the coupled systems. This will lead to the emergency of spatiotemporal intermittency in the critical state.

nlin.AO↗

arXiv2012

An Empirical Investigation of Scaling Behavior in the Atmospheric Turbulence for Understanding the Underlying Cascade Process

We study the scaling behaviors in the wind velocity time series collected at the atmospheric surface layer and compare them with two commonly used cascade models, the truncated stable distribution and the log-normal model. Results show that although both models can describe the change of probability density functions from non-Gaussian to Gaussian like distributions with the increase of time scale, they can not fit the scaling behaviors observed in the probability of return and in the moments at the same time. This work provides some clues on the understanding of cascade process in the atmospheric turbulence.

physics.flu-dyn↗

arXiv2009

Crossover from a continuum study of chiral susceptibility

We derive a model-independent integral formula for chiral susceptibility and attempt to present a continuum model study of it within the framework of Dyson-Schwinger Equations. An appropriate regularization is implemented to remove the temperature-independent quadratic divergence inherent in this quantity. While it demonstrates a second-order phase transition characteristic in the chiral limit, the result obtained supports a crossover at physical current quark masses, which is in good agreement with recent lattice studies.

hep-ph↗