<p>We construct an asymptotically flat T-fold representative of a four-dimensional dyonic black-hole charge orbit in doubled type-IIB theory. Starting from the F1-P-NS5-KKM toroidal seed, an integral parabolic T-duality monodromy is imposed on an active doubled three-torus. The non-geometric data enter only through this global patching: the Reissner–Nordstrom-type term is sourced by conserved four-dimensional electric and magnetic field strengths in the doubled Kaluza–Klein/winding local system, not by an internal algebraic <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$Q$</EquationSource> <EquationSource Format="MATHML"><math> <mi>Q</mi> </math></EquationSource> </InlineEquation>-flux alone. Exact duality preserves the local equations, the BPS index and the <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$O(6,6)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>O</mi> <mo stretchy="false">(</mo> <mn>6</mn> <mo>,</mo> <mn>6</mn> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>-invariant of the NS–NS/<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$N=4$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>N</mi> <mo>=</mo> <mn>4</mn> </mrow> </math></EquationSource> </InlineEquation> charge sublattice governing the entropy. The minimal Einstein–Maxwell dilaton slice contains a running scalar branch and an equal-charge Reissner–Nordstrom limit; the extremal near-horizon region is locally <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\textrm{AdS}_2\times S^2$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>AdS</mtext> <mn>2</mn> </msub> <mo>×</mo> <msup> <mi>S</mi> <mn>2</mn> </msup> </mrow> </math></EquationSource> </InlineEquation>, with the compact factor globally T-duality patched.</p>

A T-fold black hole in doubled type IIB

期刊论文
发表日期：

2026年7月21日

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Mir Faizal,
Arshid Shabir

摘要

We construct an asymptotically flat T-fold representative of a four-dimensional dyonic black-hole charge orbit in doubled type-IIB theory. Starting from the F1-P-NS5-KKM toroidal seed, an integral parabolic T-duality monodromy is imposed on an active doubled three-torus. The non-geometric data enter only through this global patching: the Reissner–Nordstrom-type term is sourced by conserved four-dimensional electric and magnetic field strengths in the doubled Kaluza–Klein/winding local system, not by an internal algebraic $Q$ $Q$ -flux alone. Exact duality preserves the local equations, the BPS index and the $O(6,6)$ $O (6, 6)$ -invariant of the NS–NS/ $N=4$ $N = 4$ charge sublattice governing the entropy. The minimal Einstein–Maxwell dilaton slice contains a running scalar branch and an equal-charge Reissner–Nordstrom limit; the extremal near-horizon region is locally $\textrm{AdS}_2\times S^2$ ${AdS}_{2} \times S^{2}$ , with the compact factor globally T-duality patched.