1,678 research outputs found
Lyapunov exponent, universality and phase transition for products of random matrices
Products of i.i.d. random matrices of size are related to
classical limit theorems in probability theory ( and large ), to
Lyapunov exponents in dynamical systems (finite and large ), and to
universality in random matrix theory (finite and large ). Under the two
different limits of and , the local singular value
statistics display Gaussian and random matrix theory universality,
respectively.
However, it is unclear what happens if both and go to infinity. This
problem, proposed by Akemann, Burda, Kieburg \cite{Akemann-Burda-Kieburg14} and
Deift \cite{Deift17}, lies at the heart of understanding both kinds of
universal limits. In the case of complex Gaussian random matrices, we prove
that there exists a crossover phenomenon as the relative ratio of and
changes from to : sine and Airy kernels from the Gaussian Unitary
Ensemble (GUE) when , Gaussian fluctuation when ,
and new critical phenomena when . Accordingly,
we further prove that the largest singular value undergoes a phase transition
between the Gaussian and GUE Tracy-Widom distributions.Comment: Therems 1.1 stated in a more intuitive way; proofs extensively
revised; convergence in trace norm for the critical and subcritical cases
added; 35 pages, 3 figure
Connecting Software Metrics across Versions to Predict Defects
Accurate software defect prediction could help software practitioners
allocate test resources to defect-prone modules effectively and efficiently. In
the last decades, much effort has been devoted to build accurate defect
prediction models, including developing quality defect predictors and modeling
techniques. However, current widely used defect predictors such as code metrics
and process metrics could not well describe how software modules change over
the project evolution, which we believe is important for defect prediction. In
order to deal with this problem, in this paper, we propose to use the
Historical Version Sequence of Metrics (HVSM) in continuous software versions
as defect predictors. Furthermore, we leverage Recurrent Neural Network (RNN),
a popular modeling technique, to take HVSM as the input to build software
prediction models. The experimental results show that, in most cases, the
proposed HVSM-based RNN model has a significantly better effort-aware ranking
effectiveness than the commonly used baseline models
Universality for products of random matrices I: Ginibre and truncated unitary cases
Recently, the joint probability density functions of complex eigenvalues for
products of independent complex Ginibre matrices have been explicitly derived
as determinantal point processes. We express truncated series coming from the
correlation kernels as multivariate integrals with singularity and investigate
saddle point method for such a type of integrals. As an application, we prove
that the eigenvalue correlation functions have the same scaling limits as those
of the single complex Ginibre ensemble, both in the bulk and at the edge of the
spectrum. We also prove that the similar results hold true for products of
independent truncated unitary matrices.Comment: 41 pages; revised upon the suggestions of the anonymous referees; to
appear in International Mathematics Research Notices. in IMRN 201
Temperature dependence of circular DNA topological states
Circular double stranded DNA has different topological states which are
defined by their linking numbers. Equilibrium distribution of linking numbers
can be obtained by closing a linear DNA into a circle by ligase. Using Monte
Carlo simulation, we predict the temperature dependence of the linking number
distribution of small circular DNAs. Our predictions are based on flexible
defect excitations resulted from local melting or unstacking of DNA base pairs.
We found that the reduced bending rigidity alone can lead to measurable changes
of the variance of linking number distribution of short circular DNAs. If the
defect is accompanied by local unwinding, the effect becomes much more
prominent. The predictions can be easily investigated in experiments, providing
a new method to study the micromechanics of sharply bent DNAs and the thermal
stability of specific DNA sequences. Furthermore, the predictions are directly
applicable to the studies of binding of DNA distorting proteins that can
locally reduce DNA rigidity, form DNA kinks, or introduce local unwinding.Comment: 15 pages in preprint format, 4 figure
- …