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Pabitra Barman

Publications and source records attributed to Pabitra Barman.

3 recordsLinked to original sources

Entropy and domination for quasi-Hitchin representations

Let $S$ be a closed oriented surface of genus $g\geq 2$. We consider an $n$-pleated representation $\rho: \pi_1(S) \to \mathrm{PSL}_n(\mathbb{C})$ obtained by bending a Hitchin representation $\rho_0:\pi_1(S) \to \mathrm{PSL}_n(\mathbb{R})$ along a maximal geodesic lamination. The space of such $n$-pleated representations was recently introduced by Maloni-Martone-Mazzoli-Zhang who provided a parametrization via shear-bend cocycles. Our first result is that $\rho_0$ dominates $\rho$ in the Hilbert length spectrum and the translation-length spectrum; this generalizes our earlier result for finite laminations on punctured surfaces. Using this, we prove entropy rigidity results: namely, the Hilbert entropy of a quasi-Hitchin representation in the bending fiber is strictly greater than that of $\rho_0$, and the same for the translation-length entropy in the case that $\rho_0$ is $n$-Fuchsian. The proof involves analyzing the weighted planar networks for finite approximants of the monodromy matrix, and establishing a strict domination for \emph{most} curves using the equidistribution of closed geodesics in the unit tangent bundle of $S$.

math.GT

On the domination of surface-group representations in $\mathrm{PU}(2,1)$

This article explores surface-group representations into the complex hyperbolic group $\mathrm{PU}(2,1)$ and presents domination results for a special class of representations called $T$-bent representations. Let $S_{g,k}$ be a punctured surface of negative Euler characteristic. We prove that for a $T$-bent representation $ρ: π_1(S_{g,k}) \rightarrow \mathrm{PU}(2,1)$, there exists a discrete and faithful representation $ρ_0: π_1(S_{g,k}) \rightarrow \mathrm{PO}(2,1)$ that dominates $ρ$ in the Bergman translation length spectrum, while preserving the lengths of the peripheral loops.

math.GT

Dominating surface-group representations via Fock-Goncharov coordinates

Let $S$ be a punctured surface of negative Euler characteristic. We show that given a generic representation $ρ:π_1(S) \rightarrow \mathrm{PSL}_n(\mathbb{C})$, there exists a positive representation $ρ_0:π_1(S) \rightarrow \mathrm{PSL}_n(\mathbb{R})$ that dominates $ρ$ in the Hilbert length spectrum as well as in the translation length spectrum, for the translation length in the symmetric space $\mathbb{X}_n= \mathrm{PSL}_n(\mathbb{C})/\mathrm{PSU}(n)$. Moreover, the $ρ_0$-lengths of peripheral curves remain unchanged. The dominating representation $ρ_0$ is explicitly described via Fock-Goncharov coordinates. Our methods are linear-algebraic, and involve weight matrices of weighted planar networks.

math.GT