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Weronika Wiesiolek

Publications and source records attributed to Weronika Wiesiolek.

2 recordsLinked to original sources

What is the group of a quantum group? From $SL_q(2)$ to MPO representations of $SL(2)$

Generalized symmetries realized by matrix product operators (MPOs) have so far been tied to discrete data leaving continuous symmetries outside the framework. Quantum groups fill this gap: starting from the RTT relations of $SL_q(2)$ at an odd root of unity $q^d=1$, we construct a three-parameter family of periodic-boundary MPOs of bond dimension $d^2$ that multiply according to the group law of $SL(2)$. This gives Lusztig's quantum Frobenius map a concrete operator form, and endows the XXZ chain on the ring at $Δ=(q+q^{-1})/2$ with an intrinsically non-local $SU(2)$ symmetry. Fusion of the local tensors is generically semisimple. On special loci it is non-semisimple, and yields reducible but indecomposable tensors with Jordan blocks. Differentiating $\mathcal{D}(g)$ at the identity produces the $\mathfrak{sl}(2)$ generators as $d$-body operators: the MPO algebra supplies the exponential map for quantum group algebras.

cond-mat.stat-mech↗

Les Houches Lecture Notes on Tensor Networks

Tensor networks provide a powerful new framework for classifying and simulating correlated and topological phases of quantum matter. Their central premise is that strongly correlated matter can only be understood by studying the underlying entanglement structure and its associated (generalised) symmetries. In essence, tensor networks provide a compressed, holographic description of the complicated vacuum fluctuations in strongly correlated systems, and as such they break down the infamous many-body exponential wall. These lecture notes provide a concise overview of the most important conceptual, computational and mathematical aspects of this theory.

cond-mat.str-el↗