arXiv subjects

Jorge Littin

Publications and source records attributed to Jorge Littin.

4 recordsLinked to original sources

arXiv2022

Existence of the zero temperature limit of equilibrium states on topologically transitive countable Markov shifts

Consider a topologically transitive countable Markov shift $Σ$ and a summable Markov potential $ϕ$ with finite Gurevich pressure and $\mathrm{Var}_1(ϕ) < \infty$. We prove existence of the limit $\lim_{t \to \infty} μ_t$ in the weak$^\star$ topology, where $μ_t$ is the unique equilibrium state associated to the potential $tϕ$. Besides that, we present examples where the limit at zero temperature exists for potentials satisfying more general conditions.

math.DS↗

arXiv2020

Time-fractional Birth and Death Processes

In this article, we provide different representations for a time-fractional birth and death process $N_α(t)$, whose transition probabilities are governed by a time-fractional system of differential equations. More specifically, we present two equivalent characterizations for its trajectories: the first one as a time-changed classic birth and death process, whereas the second one is a Markov renewal process. Also, we provide results for the asymptotic behavior of the process conditioned not to be killed. The most important is that the concept of quasi-limiting distribution and quasi-stationary distribution do not coincide, which is a consequence of the long-memory nature of the process. As an application example, we revisit the linear case to show the consequences of our main theorems.

math.PR↗

arXiv2017

Poisson Statistics in the Non-Homogeneous Hierarchical Anderson Model

In this article we study the problem of localization of eigenvalues for the non-homogeneous hierarchical Anderson model. More specifically, given the hierarchical Anderson model with spectral dimension $0<d<1$ with a random potential acting on the diagonal of non i.i.d. random variables, sufficient conditions on the disorder are provided in order to obtain the two main results: the weak convergence of the counting measure for almost all realization of the random potential and the weak convergence of the re-scaled eigenvalue counting measure to a Poisson point process. The technical part improves the already existing arguments of Kritchevski , who studied the hierarchical model with a disorder acting on the diagonal, with independent and identically distributed random variables, by using the argument of Minami . At the end of this article, we study an application example that allows us to understand some relations between the spectral dimension of the hierarchical Laplacian and the magnitude of the disorder.

math.PR↗

arXiv2010

R-positivity of matrices and Hamiltonians on nearest neighbors trajectories

We revisit the $R-$positivity of nearest neighbors matrices on ${\ZZ_+}$ and the Gibbs measures on the set of nearest neighbors trajectories on ${\ZZ_+}$ whose Hamiltonians award either visits to sites a or visits to edges. We give conditions that guarantee the $R-$positivity or equivalently the existence of the infinite volume Gibbs measure, and we show geometrical recurrence of the associated Markov chain. In this work we generalize and sharpen results obtained in [3] and [6].

math.PR↗