Quantum Spacetime: Gravity, Black Holes, Cosmology, and Information Program

Spring 2030: Black Holes, Holography, and Quantum Information

Black holes force gravity, quantum theory, thermodynamics, and information into the same calculation. Semiclassical Hawking radiation raises the information problem; holographic duality makes parts of gravitational physics accessible through nongravitational quantum systems; quantum-information language has clarified reconstruction, entanglement, and error-correction structures; island and replica-wormhole calculations provide controlled settings in which radiation entropies follow a unitary Page curve. The frontier is to determine which conclusions are structural, which depend on holography or semiclassical control, and how locality and spacetime emerge from the underlying quantum description.

  • A first cluster concerns entropy and subsystem structure in gauge and gravitational theories, where ordinary tensor-factor decompositions can fail.
  • A second concerns information recovery: what exactly is established by Page-curve, island, and replica calculations, and how far can those conclusions be extended?
  • A third concerns bulk reconstruction and emergent locality, including the relation between holographic reconstruction and quantum error-correcting structure. Entanglement and complexity provide further probes, but their geometric interpretation must be separated carefully from framework-dependent conjectures. Black-hole dynamics, semiclassical gravity, and quantum field theory supply benchmark calculations for these comparisons.

At TIAMS, working groups will focus on quantities that can be defined and computed: generalized entropy, reconstruction maps, algebra algebras of observables, relative entropy or related diagnostics, semiclassical saddle contributions, and controlled toy models. Tutorials will align gravity and information-theoretic vocabulary. Participants will test how conclusions change when assumptions about asymptotics, coupling, code subspaces, factorization, or semiclassical limits are modified. Progress may be a new entropy calculation, a sharper reconstruction theorem, a counterexample delimiting a conjecture, a bridge between relational observables and information algebras, or a precise account of which features of information recovery persist outside an idealized holographic setting. Comparing algebraic, semiclassical, and information-theoretic formulations on the same toy model can expose whether two statements are actually equivalent or only share suggestive language. This comparison also creates tractable questions for researchers entering from neighboring mathematical fields.

  • How should gravitational and entanglement entropy be defined when gauge constraints and dynamical geometry obstruct ordinary subsystem decompositions?
  • What do Page-curve, island, and replica-wormhole calculations establish about information recovery, and which assumptions are essential?
  • How is bulk information encoded and reconstructed in holographic theories, and what role does quantum error-correcting structure play?
  • Which notions of locality and relational observables survive in a fully gravitational quantum system?
  • What can entanglement and complexity reliably tell us about the emergence of semiclassical spacetime?
  • Which black-hole information statements remain meaningful beyond the most controlled holographic or semiclassical regimes?

  • Black-hole information
  • Gravitational and entanglement entropy
  • Page curves, islands, and replica methods
  • Holographic duality and bulk reconstruction
  • Quantum error-correcting structure
  • Relational observables and locality
  • Entanglement and complexity
  • Semiclassical gravity

  • Parampreet Singh — TIAMS scientific lead; LSU

The semester should open with joint tutorials in black-hole physics, holography, gravitational entropy, and quantum-information concepts. A focused workshop can then establish benchmark calculations and open problems. March and April should be reserved for working groups on entropy, reconstruction, observables, and semiclassical limits, with a smaller intensive selected from those groups. A final synthesis should compare which statements are framework independent, which rely on holography, and which remain conjectural.

Preliminary Workshops, Schools, or Focused Meetings

Opening tutorials on black holes, holography, and quantum information

dates TBA

Focused workshop on entropy, islands, reconstruction, and information recovery

dates TBA

Working-group intensive on observables, locality, and semiclassical emergence

dates TBA

Semester and year synthesis meeting

dates TBA

Seminars and Working Groups

  • Entropy and subsystem structure: generalized entropy, gauge constraints, factorization, and algebraic descriptions.
  • Page curves and islands: assumptions, semiclassical saddles, and regimes of control.
  • Bulk reconstruction: code-subspace structure, reconstructable regions, and limits of locality.
  • Relational observables and emergence: compare gravitational observables with information-theoretic descriptions of spacetime.

The semester is intended for researchers in quantum gravity, string theory, holography, black-hole physics, quantum field theory, quantum information, mathematical physics, and related parts of general relativity. Faculty, postdoctoral researchers, and graduate students are invited. Researchers in operator algebras, information theory, quantum error correction, geometry, and semiclassical analysis should participate when their tools sharpen subsystem structure, reconstruction, or observables. The program is designed to support serious comparison among holographic, canonical, information-theoretic, and other gravity viewpoints. Researchers developing solvable models or numerical experiments are also valuable when those models make assumptions and information flow especially transparent. Mathematicians working on operator algebras, constrained systems, or information geometry may find concrete entry points through subsystem and observable questions.

  • Extended residence around a benchmark problem.
  • One- to three-month research visits overlapping with active working groups.
  • Short technical visits for a calculation or comparison.
  • Tutorial/research-school and workshop participation.
  • Weekly seminars and informal working sessions.
  • Expression of interest through the TIAMS participation form.

Junior researchers should leave the tutorial period able to follow at least one benchmark calculation from both the gravity and information sides. Working groups will provide concrete tasks involving entropy, reconstruction, observables, or semiclassical approximations. Students and postdocs will be encouraged to reproduce known calculations before modifying assumptions, present partial results frequently, and develop the habit of distinguishing a controlled result from a persuasive analogy or conjecture. Cross-field mentoring should help them learn which technical steps are standard in one community but nontrivial or controversial in another.

Possible outcomes include entropy and Page-curve calculations, sharper reconstruction statements, controlled tests of island or replica methods, algebraic formulations of subsystem/observable questions, comparisons of relational and holographic observables, open-problem documents, computational tools, and collaborations linking gravity and information theory.

Use the TIAMS Program Participation form to describe the black-hole, holographic, or information-theoretic question you want to study, the framework you work in, preferred dates, and any support request.