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Fuat Berkin Altunkaynak

Publications and source records attributed to Fuat Berkin Altunkaynak.

2 recordsLinked to original sources

Computational Cosmic Censorship

We identify a two-gap complexity structure underlying a holographic obstruction to reaching extremality and to the black-hole-mediated route toward weak cosmic censorship violation. The complexity of formation of extremal AdS black holes diverges logarithmically, while it is finite for every subextremal member of the stationary family. We compute the on-shell Wheeler--DeWitt action of overcharged Reissner--Nordström--AdS in general dimension $D\geq4$. In the minimal prescription, defined by omission of the Maxwell boundary term, the individually divergent Maxwell bulk, on-shell Einstein--Hilbert, and Gibbons--Hawking--York terms cancel exactly. We also evaluate the null--timelike joints and null-boundary counterterms explicitly and show that their combined lower-endpoint contribution vanishes. Adding the Maxwell boundary term produces only a prescription-dependent, regulator-local power-law divergence; no prescription produces a logarithmic divergence, and the corresponding vacuum-subtracted complexity=volume complexity of formation is finite. In the complexity=action and complexity=volume prescriptions, the reverse triangle inequality for complexity distance then implies divergent relative complexity across each adjacent gap. Under a finite-complexity-growth assumption, this gives a conditional obstruction to traversing the stationary path from subextremal black holes through extremality to the superextremal naked-singularity sector.

hep-th↗

Area Monotonicity of Wormhole Throats and a Geometric Bound on Information Transfer

We develop a semiclassical geometric framework to constrain information transfer through traversable wormholes. This study is motivated by the growing intersection between spacetime geometry and quantum information theory, specifically the ER=EPR conjecture and the bit-thread formulation of holographic entropy. First, we prove a geometric monotonicity result for traversable wormhole throats, demonstrating that after a traversable window is established via an averaged null energy condition (ANEC) violating deformation, any subsequent signal-carrying matter satisfying the pointwise null energy condition (NEC) causes the throat cross-sectional area to be non-increasing. Second, we utilize this monotonicity to derive a semiclassical geometric upper bound on the number of independent quantum degrees of freedom (qubits) transmissible through the wormhole. This bound $Q_{\max} \leq A_{\min}/4G_N$, is motivated via the Max-Flow Min-Cut theorem for bit threads and interpreted as a geometric proxy for the holographic capacity of a quantum teleportation channel. We further discuss a holographic tensor-network analogy based on the HaPPY code, where the discrete max-flow/min-cut theorem provides an illustrative graph-theoretic counterpart of the bottleneck structure. Our results identify the wormhole throat as a natural geometric bottleneck, providing a geometric perspective on information-transfer limits in semiclassical gravity.

gr-qc↗