REVIEW 30 cited by
Transcending the ensemble: baby universes, spacetime wormholes, and the order and disorder of black hole information
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
Signed reviews
abstract
In the 1980's, work by Coleman and by Giddings and Strominger linked the physics of spacetime wormholes to `baby universes' and an ensemble of theories. We revisit such ideas, using features associated with a negative cosmological constant and asymptotically AdS boundaries to strengthen the results, introduce a change in perspective, and connect with recent replica wormhole discussions of the Page curve. A key new feature is an emphasis on the role of null states. We explore this structure in detail in simple topological models of the bulk that allow us to compute the full spectrum of associated boundary theories. The dimension of the asymptotically AdS Hilbert space turns out to become a random variable $Z$, whose value can be less than the naive number $k$ of independent states in the theory. For $k>Z$, consistency arises from an exact degeneracy in the inner product defined by the gravitational path integral, so that many a priori independent states differ only by a null state. We argue that a similar property must hold in any consistent gravitational path integral. We also comment on other aspects of extrapolations to more complicated models, and on possible implications for the black hole information problem in the individual members of the above ensemble.
Forward citations
Cited by 30 Pith papers
-
Fundamental Complement of a Gravitating Region
A gravitating region's hologram is the spacelike complement of the hologram of its fundamental complement, generalizing entanglement-wedge complementarity to arbitrary spacetimes and recovering AdS/CFT.
-
An entropic puzzle in periodic dilaton gravity and DSSYK
Gauging a momentum shift symmetry in sine dilaton gravity yields the DSSYK spectrum, makes negative-length states null, and predicts a finite entropy S=2πθ−2θ² instead of the Bekenstein-Hawking area law.
-
Relational path integral, effective actions and quantum frame covariance in gravity
The gravitational path integral is reformulated with dynamical reference frames, producing gauge-invariant correlators, frame-dependent vacua, and effective actions, with sharpness of events becoming frame-relative.
-
Bootstrapping black holes at low impact parameter
After subtracting the eikonal carrier, the residual SDR spectrum in six dimensions organizes into a cap-saturated low-impact band, an empty gap, and Regge-like ridges whose weak-coupling edge is the G_N=0 baseline.
-
Evaporating Black Hole Interior and Complexity Evolution
In JT gravity with an end-of-the-world brane, the renormalized interior length — read as subsystem complexity — grows linearly, peaks around the Page time, and then decays exponentially, with growing relative fluctuat...
-
Observer complementarity for black holes and holography
The authors show that the observer rule of Harlow, Usatyuk, and Zhao yields a self-consistent black hole complementarity for both partially and fully evaporated black holes.
-
A Nonperturbative Toolkit for Quantum Gravity
A shell-state resolution of the identity, an infinite-overcompleteness limit, and geometric surgery are claimed to prove fine-grained factorization of the two-sided gravitational thermal partition function.
-
Further Evidence Against a Semiclassical Baby Universe in AdS/CFT
A bulk swap operator, reconstructed on the boundary, shows that the CFT state in the Antonini-Rath construction is dual to the spacetime without a semiclassical baby universe, forcing any encoded baby universe to have...
-
A microscopic realization of dS$_3$
Pure dS3 quantum gravity is claimed to be dual to the complex Liouville string's matrix integral, with integrated cosmological correlators equal to resolvent correlators and de Sitter entropy equal to 2 log of the eig...
-
QG from SymQRG: AdS$_3$/CFT$_2$ Correspondence as Topological Symmetry-Preserving Quantum RG Flow
A framework called SymQRG identifies 3D quantum gravity as the symmetry-preserving RG flow of 2D CFTs, realized discretely by U_q(SL(2,R)) 6j symbols.
-
A single geometry from an all-genus expansion in quantum gravity
The all-genus JT gravity path integral at beta ~ e^{2S0/3} is reproduced at leading order by a disk path integral with a cubic, nonlocal dilaton interaction.
-
Revisiting wormhole-induced global symmetry breaking
Ensemble averaging over wormhole α-parameters is dominated by the symmetric point α=0 for spontaneously broken U(1) p-form symmetries, so standard PQ models evade the wormhole-induced axion quality problem.
-
Matrix Multiverses Meet Multiple Mythologies
The authors construct a model where asymptotically de Sitter universes are finite-entropy subsystems inside black holes in a maximal-entropy p=ρ universe, decaying on timescales far shorter than recurrence times.
-
Holographic RG flows and wormholes from sinusoidal scalars
For d=3, Δ=2 Einstein-scalar gravity with sinusoidal sources on two R^3 boundaries, the large wormhole dominates the path integral whenever wormholes exist, and there is no Hawking-Page-like subdominant regime.
-
Ramp, Plateau, and Wormholes without Averaging, and Hyper-non-perturbative Structures in Gravity
Smooth filter projection of erratic spectral data reproduces random-matrix ramp and plateau in a single chaotic system, and predicts double-exponential hyper-nonperturbative effects in holographic gravity.
-
A Holographic Map from AdS$_3$ to CFT$_2$
Semiclassical pure AdS3 gravity states, labelled by fixed-area geodesic networks, are mapped to CFT2 primary states whose wavefunctions are networks of OPE coefficients.
-
The $\alpha$-states of a string worldsheet
The α-states of the Hurwitz worldsheet are symmetric-group characters weighted by the Poissonized Plancherel measure, so string amplitudes are ensemble averages whose weak-coupling limit is Kerov's central limit theorem.
-
Non-invertible symmetries in the axiverse, and the imaginary wormholes
Imaginary wormholes and the IDB imply that towers of BPS EFT instantons generate infinitely many superpotential terms that break non-invertible axion shift symmetries in N=1 axiverse models.
-
The many facets of a hyperbolic tetrahedron: open and closed triangulations of 3d gravity
Open Virasoro TQFT equals fixed-length/angle 3d gravity path integrals on compact regions and yields the CTV–scalar Virasoro relation via open-closed duality.
-
Baby Universes from Thermal Pure States in SYK
A JT-gravity baby universe is constructed with a microscopic dual given by a low-temperature thermal pure state of two coupled SYK models, and its bulk entanglement to the AdS region is O(N) below the phase transition.
-
Observing Spacetime
An asymptotic observer can check a proposed quantum gravity microstate with a probe tuned to the state's creating operator, because extra wormhole saddles make the response O(1) larger than any generic probe.
-
Observers and Timekeepers: From the Page-Wootters Mechanism to the Gravitational Path Integral
Metric summation produces the problem of time, topology summation produces the one-dimensional Hilbert space, and a timekeeper path integral gives observer-dependent holography.
-
How to Count States in Gravity
The Gibbons-Hawking Euclidean gravity path integral with periodic time equals an explicit thermal trace over the single-boundary quantum gravity Hilbert space.
-
Nonperturbative Quantum Gravity in a Closed Lorentzian Universe
In a closed universe with a one-dimensional Hilbert space per alpha-microstate, tracing out unobserved environmental degrees of freedom yields robust, einselected probabilities with errors exponentially suppressed by ...
-
Quantum mechanics and observers for gravity in a closed universe
An observer inside a closed universe gets an approximately standard quantum description on a Hilbert space of dimension about e^{their entropy}, accurate up to exponentially small errors.
-
Conformal Cores of Quantum Black Holes in Quadratic Gravity
Exact complex power-law solutions of pure quadratic gravity, named powerballs, can match a Schwarzschild black hole just outside its horizon and give a finite-action model of the quantum interior.
-
Junctions, strings, clocks and gravitational memory in three dimensional dS space
Transient closed-string fluctuations in dS3 are shown order by order to be encoded in gravitational junction shifts at I±, with the monotonic time shift forming an emergent clock.
-
The Baby Universe is Fine and the CFT Knows It: On Holography for Closed Universes
A closed universe in AdS/CFT is not ruled out by recent SWAP-test arguments; the one-dimensional Hilbert space seen from the CFT is external indistinguishability, and CFT data can reconstruct the closed universe's geometry.
-
Replica Wormholes, Modular Entropy, and Capacity of Entanglement in JT Gravity
In JT gravity toy models, late-time modular entropy and capacity of entanglement scale inversely with n times the inverse temperature, supporting a thermal reading of the replica parameter.
-
Half-Wormholes in a Supersymmetric SYK Model
Half-wormholes restore factorization in the one-time-point N=1 supersymmetric SYK model, and both wormholes and half-wormholes break supersymmetry.
Discussion (0). Continue with ORCID to comment.