We study the entanglement entropy of gauged internal degrees of freedom in a two dimensional symmetric product orbifold CFT, whose configurations consist of N strands sewn together into ``long'' strings, with wavefunctions symmetrized under permutations. In earlier work a related notion of ``entwinement'' was introduced. Here we treat this system analogously to a system of N identical particles. From an algebraic point of view, we point out that the reduced density matrix on k out of N particles is not associated with a subalgebra of operators, but rather with a linear subspace, which we explain is sufficient. In the orbifold CFT, we compute the entropy of a single strand in states holographically dual in the D1/D5 system to a conical defect geometry or a massless BTZ black hole and find a result identical to entwinement. We also calculate the entropy of two strands in the state that represents the conical defect; the result differs from entwinement. In this case, matching entwinement would require finding a gauge-invariant way to impose continuity across strands.
Original languageEnglish
Article number190
Number of pages21
JournalJournal of High Energy Physics
Issue number1
Publication statusPublished - 24 Jan 2019

    Research areas

  • AdS-CFT Correspondence, Conformal Field Theory, Field Theories in Lower Dimensions, Gauge Symmetry

ID: 43924765