arXiv subjects

Xiantong Chen

Publications and source records attributed to Xiantong Chen.

5 recordsLinked to original sources

arXiv2026

Long-range multipartite entanglement in holographic gapless systems

Gapless quantum systems support correlations over arbitrarily long distances, giving rise to power-law long-range entanglement. We investigate long-range entanglement at strong coupling for three-dimensional gapless systems using holography, asking whether multipartite entanglement can exhibit scale-growing behavior and become enhanced at large distances. We show that a broad class of multipartite entanglement quantities share the same leading large-distance scaling exponent determined by the IR geometry. To realize different scaling regimes, we consider hyperscaling-violating IR geometries. Depending on the parameters, long-distance multipartite entanglement can decay, become logarithmic, grow subextensively, or reach a volume law. We also analyze an anisotropic IR geometry $\mathrm{AdS}_{3}\times\mathbb{R}^{2}$, where long-range multipartite entanglement survives along one direction but becomes short-ranged in the transverse gapped directions. These results show that holographic gapless phases can support rich and enhanced long-range multipartite entanglement, providing a nonlocal characterization of the underlying IR physics.

hep-th↗

arXiv2026

Detecting Topological Transitions and Anisotropy through Multipartite Entanglement in Holographic Weyl Semimetals

We study multipartite entanglement structures in the zero-temperature holographic Weyl semimetal, focusing on tripartite and four-partite structures. For strip regions, we compute the conditional mutual information, the entanglement wedge cross section, tripartite measures $\kappa$ and the Markov gap, multi-EWCS, and two multi-EWCS based four-partite signals $\Delta$ and $g$. These quantities are studied as functions of the strip width $l$ and the tuning parameter across the topological transition. At large $l$, their $l$ dependence takes a power-law form governed by the IR scaling of the system. At fixed large $l$, all these entanglement quantities develop clear features near the critical point, showing that tripartite and four-partite entanglement structures can diagnose the topological quantum phase transition. We further study strips pointing in different directions to probe the anisotropy of the system. The anisotropic large l behavior distinguishes the nontrivial phase from the trivial phase. These results establish multipartite holographic entanglement as a sensitive, nonlocal probe of topological phase transitions and anisotropic IR physics.

hep-th↗

arXiv2026

Multipartite entanglement characterizing topological phase transitions in holographic nodal line semimetals

Topological states of matter are characterized by nonlocal structures that are naturally encoded in the quantum entanglement of many-body wavefunctions. Topological semimetals are short-range entangled states at weak coupling and their entanglement structure at strong coupling remains largely unexplored. In this work, we investigate the multipartite entanglement structure of strongly coupled holographic nodal line semimetals. Building on previous studies of entanglement entropy and the holographic c-function, we focus on multipartite entanglement measures, including the conditional mutual information, multi-entropy, and the Markov gap which is based on the entanglement wedge cross section. Our results demonstrate that while these multipartite measures vanish in the long-distance limit $l \to \infty$, which confirms that the holographic nodal line semimetal remains a short-range entangled state, their large $l$ scaling behavior remains highly sensitive to the underlying topology. The large $l$ power-law decay and scaling exponents serve as robust, non-local order parameters that exhibit sharp changes at the quantum critical point. This work establishes multi-partite entanglement as a powerful probe of quantum topological phase transitions in strongly coupled topological systems.

hep-th↗

arXiv2025

Topological invariant for holographic Weyl-Nodal line coexisting semimetal

The presence of a topological phase in a topological many-body system can be distinguished through the analysis of topological invariants. In the present study, the topological invariants for the strongly coupled holographic semimetals have been systematically computed, especially focusing on the holographic Weyl-Nodal line coexisting semimetal. The topological invariants that we calculate include the Weyl charge, the topological charges for a nodal ring $\zeta_0$, $\zeta_1$, $\zeta_2$ and an additional mirror symmetry protected topological invariant, $\widetilde{\zeta}_{2}$, that we herein introduce. In addition, the effective band structures and topological invariants in the critical phases of holographic semimetals are investigated, including the case of Weyl, nodal line and Weyl-Nodal line coexisting semimetals. The findings indicate the presence of notable and unique features inherent to strongly coupled topological semimetals, including band-crossing ordering interchange and multi Fermi surfaces, which provide a valuable platform for experimental investigations of strongly coupled semimetals in condensed matter physics.

hep-th↗

arXiv2025

Topological invariant for holographic Weyl-$\mathrm Z_2$ semimetal

The occurrence of a topological phase transition can be demonstrated by a direct observation of a change in the topological invariant. For holographic topological semimetals, a topological Hamiltonian method needs to be employed to calculate the topological invariants due to the strong coupling nature of the system. We calculate the topological invariants for the holographic Weyl semimetal and the holographic Weyl-$\mathrm Z_2$ semimetal, which correspond to the chiral charge and the spin-Chern number, respectively. This is achieved by probing fermions within the system and deriving the topological Hamiltonian from the zero-frequency Green's function. In both cases, we have identified an effective band structure characterized by an infinite number of Weyl or $\mathrm Z_2$ nodes, a distinctive feature of holographic systems different from weakly coupled systems. The topological invariants of these nodes are computed numerically and found to be nonzero, thereby confirming the topologically nontrivial nature of these nodes.

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