Wormholes and the Fabric of Reality

Author: Denis Avetisyan


New research connects the geometry of wormholes to the mathematical structures of matrix models, offering insights into the holographic principle.

The geometry collapses to a conformal boundary defined by the limit of vanishing length <span class="katex-eq" data-katex-display="false">\ell \to 0</span>, ultimately manifesting as two four-spheres connected by a shared circle <span class="katex-eq" data-katex-display="false">S^1</span>-a space upon which the delta operator resides, hinting at the fragile nature of theoretical constructs facing absolute limits.
The geometry collapses to a conformal boundary defined by the limit of vanishing length \ell \to 0, ultimately manifesting as two four-spheres connected by a shared circle S^1-a space upon which the delta operator resides, hinting at the fragile nature of theoretical constructs facing absolute limits.

This review explores the construction of multi-cover bubbling wormholes within the AdS/CFT correspondence and their relation to spectral curves and conical singularities.

Establishing a precise connection between gravitational geometries and their quantum field theory duals remains a central challenge in holographic approaches to quantum gravity. This is addressed in ‘Bubbling wormholes and matrix models’, which explores a construction linking multi-cover wormhole geometries-analogous to multi-sheeted Riemann surfaces-to sums over representations in large $N$ gauge theory. The authors demonstrate that these sums define correlation functions for half-BPS Wilson loops in a matrix model, effectively encoding information about conical singularities and spectral curves within the bulk geometry. Could this framework provide a novel pathway towards understanding the emergence of spacetime from non-perturbative quantum field theory?


The Alluring Echo: Mapping Gravity to Quantum States

The AdS/CFT correspondence, a cornerstone of modern theoretical physics, posits a startling relationship between two seemingly disparate realms: gravity and quantum mechanics. Specifically, this duality proposes that a theory of gravity in a negatively curved, five-dimensional space – known as anti-de Sitter space, or AdS5 – is mathematically equivalent to a quantum field theory residing on the four-dimensional boundary of that space. This isn’t merely an analogy; the correspondence suggests these two descriptions are fundamentally the same, offering a powerful tool to study strongly coupled quantum systems-those intractable by traditional methods-through the more manageable framework of classical gravity. Essentially, phenomena in the quantum world can be ‘mapped’ onto gravitational phenomena, and vice-versa, opening avenues to explore concepts like black holes as holographic projections of quantum states and potentially resolving long-standing puzzles in both fields.

The remarkable AdS/CFT correspondence provides a powerful tool for investigating systems where interactions are exceptionally strong – conditions notoriously difficult to address with conventional quantum field theory techniques. This duality posits a precise equivalence between a gravitational theory in anti-de Sitter space and a quantum field theory residing on its boundary, effectively translating a complex many-body problem into a problem of classical gravity. Consequently, phenomena like quantum entanglement, which typically manifest as abstract quantum correlations, can be represented geometrically as features within the gravitational spacetime – specifically, as connections resembling wormholes. The size and properties of these ‘wormhole’ geometries are directly related to the degree of entanglement between particles in the dual quantum system, offering a novel pathway to understanding entanglement through the lens of gravity and potentially revealing insights into the emergence of spacetime itself from quantum information.

The intriguing connection between quantum entanglement and the fabric of spacetime is illuminated by the concept of bubbling wormholes, solutions derived from Einstein’s equations that propose a geometric representation of entangled particles. These aren’t the traversable wormholes of science fiction, but rather fleeting, microscopic structures that emerge from the mathematical framework of general relativity. Constructing these wormholes isn’t straightforward; they demand precise configurations of energy and matter to avoid collapsing into singularities or becoming unstable. Researchers are exploring how specific arrangements of AdS_5 space, coupled with careful consideration of boundary conditions, can yield these “bubbling” geometries, effectively providing a tangible, albeit theoretical, link between the seemingly disparate realms of quantum information and gravitational physics. This careful construction is essential because the wormhole’s geometry directly reflects the degree of entanglement between the quantum particles it connects, hinting at a deeper, holographic relationship between gravity and quantum mechanics.

The rotated Young diagram, described by rectangular blocks defining row and column counts <span class="katex-eq" data-katex-display="false">\{n_I, K_I\}\_{I=1}^{g+1}</span> and constrained by <span class="katex-eq" data-katex-display="false">n_{g+1} + \sum_{I=1}^{g} n_I = N</span>, projects to a Maya diagram representing cuts of the matrix model spectral curve <span class="katex-eq" data-katex-display="false">y(z)</span> and defining the genus and shape of the dual supergravity geometry.
The rotated Young diagram, described by rectangular blocks defining row and column counts \{n_I, K_I\}\_{I=1}^{g+1} and constrained by n_{g+1} + \sum_{I=1}^{g} n_I = N, projects to a Maya diagram representing cuts of the matrix model spectral curve y(z) and defining the genus and shape of the dual supergravity geometry.

Constructing the Invisible: A Mathematical Foundation for Wormholes

The geometric structure of bubbling wormholes is fundamentally defined by harmonic functions existing on a Riemann surface, denoted as Σ. These functions, satisfying Laplace’s equation on Σ, directly parameterize the wormhole’s metric. Specifically, a metric g_{ij} can be constructed from these harmonic functions \phi_i through a specific relation, determining the spatial curvature and topology of the wormhole throat. The Riemann surface Σ acts as the natural domain for these functions, providing the necessary complex structure to accommodate the required analytic properties for a consistent geometric interpretation. Variations in the harmonic functions then correspond to deformations of the wormhole geometry, allowing for a parameterized family of solutions.

The geometric form of a bubbling wormhole is directly determined by the regularity conditions imposed on the harmonic functions defining it. Specifically, these conditions-ensuring finite energy and smoothness at the wormhole throat-constrain the function’s behavior and its derivatives. Mathematical stipulations, such as requiring the functions to satisfy specific boundary conditions on the Riemann surface Σ, translate directly into physical characteristics like the wormhole’s radius, length, and connectivity. Violations of these regularity conditions would result in singularities or unstable configurations, rendering the wormhole physically implausible. Therefore, the precise shape and topological properties of the wormhole are not arbitrary but are rigorously dictated by the mathematical constraints placed upon these harmonic functions.

The Gaussian-Penner Matrix Model, a technique originating in two-dimensional quantum gravity and integrable systems, offers a computational framework for determining the spectral curve associated with bubbling wormhole geometries. This model involves integrating over the space of Hermitian matrices, yielding a partition function whose spectral density directly relates to the eigenvalues of these matrices, which define the spectral curve. Crucially, the spectral curve encodes the information necessary to reconstruct the harmonic functions \mathcal{H} that govern the wormhole’s geometry on the Riemann surface Σ. Specifically, the poles of the spectral curve correspond to the branch points of the harmonic functions, and the residues determine the associated residues, effectively establishing a precise link between matrix model calculations and the geometric properties of the wormhole.

The bulk geometry is determined by the Riemann surface and the arrangement of cuts and poles of the functions <span class="katex-eq" data-katex-display="false">h_1</span> and <span class="katex-eq" data-katex-display="false">h_2</span> on its boundary, as illustrated by a single <span class="katex-eq" data-katex-display="false">AdS_5 \times S^5</span> region with multiple cuts representing a backreacted Wilson loop in a large <span class="katex-eq" data-katex-display="false">N^2</span> representation with nontrivial cycles <span class="katex-eq" data-katex-display="false">\mathcal{C}_D</span>.
The bulk geometry is determined by the Riemann surface and the arrangement of cuts and poles of the functions h_1 and h_2 on its boundary, as illustrated by a single AdS_5 \times S^5 region with multiple cuts representing a backreacted Wilson loop in a large N^2 representation with nontrivial cycles \mathcal{C}_D.

Probing the Phantom: Wilson Loops as Wormhole Witnesses

The Wilson Loop, a gauge-invariant observable, functions as a primary tool for characterizing the geometry of bubbling wormholes within the AdS/CFT correspondence. Specifically, calculating the expectation value of a Wilson Loop – the trace of the parallel transport matrix for a gauge field around a closed loop – provides information about the string worldsheet area subtended by that loop. Deviations in the Wilson Loop expectation value from the value predicted by the background AdS5×S5 spacetime directly indicate modifications to the geometry induced by the wormhole. These deviations are sensitive to the wormhole’s size and internal structure, offering a measurable signature of non-trivial topology and allowing for quantitative comparison with theoretical predictions regarding wormhole formation and stability. The loop’s configuration, and thus the geometry probed, can be varied to map out the influence of the wormhole on the spacetime.

Calculating the on-shell action for a probe string traversing the wormhole geometry allows for quantitative assessment of deviations from the background AdS5×S5 spacetime. This involves determining the Nambu-Goto action, S = -T \in t d\tau d\sigma \sqrt{\det(\partial_\tau X \cdot \partial_\tau X)}, for a string embedded within the perturbed metric. Minimizing this action with respect to the string’s embedding coordinates yields the equations of motion, which, when solved, reveal how the wormhole geometry alters the string’s energy and tension. Analyzing the resulting on-shell action, particularly its dependence on the wormhole parameters, provides a precise measure of the geometric distortion and allows for comparison with theoretical predictions from the dual field theory.

The inclusion of a DGP (Dvali-Gabadadze-Porrati) term within the On-Shell Action accounts for contributions arising from induced gravity effects in the wormhole geometry. This term effectively modifies the gravitational dynamics near the wormhole throat, providing a more accurate description of its influence on the background spacetime. Quantitative analysis, specifically through free energy calculations, demonstrates that the contribution from the DGP term scales with N^2/\lambda^{1/2}, where N represents the rank of the gauge group and λ is the ‘t Hooft coupling. This scaling behavior confirms the theoretical prediction and validates the inclusion of the DGP term as a necessary refinement to the model of wormhole dynamics.

The on-shell action for a Wilson loop on a disk of radius <span class="katex-eq" data-katex-display="false">R</span> reveals a conical singularity at its origin.
The on-shell action for a Wilson loop on a disk of radius R reveals a conical singularity at its origin.

Beyond Simplicity: The Four-Cover Wormhole and its Implications

The introduction of the four-cover bubbling wormhole significantly amplifies the geometric intricacy inherent in these theoretical spacetime structures. This complexity isn’t merely visual; it’s mathematically underpinned by the Delta Operator, a tool demonstrating connections between seemingly unrelated Gaussian matrix models. This operator reveals a specific scaling behavior in the wormhole’s free energy – a value of -{80}/(3π²)N²/λ^(1/2) – where N represents the matrix size and λ governs the strength of interactions. This particular scaling provides crucial insights into the quantum properties of the wormhole, suggesting a deeper relationship between gravity, quantum mechanics, and the underlying mathematical structures governing spacetime itself, and indicating a more nuanced energy distribution than previously considered in simpler wormhole models.

The construction of this wormhole geometry, leveraging harmonic functions defined on a Riemann surface, dramatically expands the possibilities for investigating quantum entanglement. By mapping entanglement structures onto the geometric features of this surface, researchers gain access to a more nuanced and complex landscape than previously available. This approach allows for the exploration of entanglement in scenarios involving non-trivial topology and curvature, potentially revealing connections between entanglement and spacetime geometry. The richer structure facilitates the study of how entanglement manifests across different regions of spacetime, offering insights into the holographic principle and the nature of quantum gravity. Furthermore, the geometric representation provides a powerful tool for visualizing and calculating entanglement measures in highly complex systems, paving the way for a deeper understanding of quantum correlations in the universe.

The construction of the two-cover wormhole relies on a specific transformation – a Two-to-One Map – which intricately connects a Riemann surface, denoted as Σ, to the geometry defining the wormhole itself. This mapping, however, doesn’t produce a smooth spacetime; instead, the resulting geometry exhibits conical singularities at three distinct points on Σ. These singularities aren’t merely mathematical curiosities, but necessitate the presence of exotic matter possessing negative energy density to resolve. The degree of this ‘conical excess’ – the angular deficit around each singularity – is precisely , indicating a substantial requirement for this unusual form of energy to maintain the wormhole’s structure and prevent it from collapsing. This geometrical feature highlights a fundamental link between the topology of spacetime and the need for potentially unphysical energy conditions in traversable wormhole solutions.

The Riemann surface describing the BW2 solution can be visualized as a disk with two cuts and simple poles, representing a lower half-plane with conical singularities <span class="katex-eq" data-katex-display="false">\otimes</span> that indicate excess.
The Riemann surface describing the BW2 solution can be visualized as a disk with two cuts and simple poles, representing a lower half-plane with conical singularities \otimes that indicate excess.

The exploration of bubbling wormholes, as detailed in this work, reveals the inherent fragility of theoretical constructs. Just as light bends around a massive object, reminding one of limitations, so too do these models-maps attempting to chart the complexities of AdS/CFT-reveal their own boundaries. Mary Wollstonecraft observed, “The mind, when once enlightened, will never be fully extinguished.” This rings true; each conical singularity identified within the spectral curves isn’t a failure of the matrix model, but rather an invitation to refine understanding, to acknowledge the point where the map ceases to perfectly reflect the territory. The persistence in mapping these structures, despite their inevitable imperfections, mirrors a determined pursuit of knowledge, even beyond the event horizon of current comprehension.

Where Do the Ripples Lead?

The construction of these multi-cover bubbling wormholes, tied as they are to matrix models and the delicate geometry of spectral curves, feels less like a resolution and more like a careful charting of the shoreline. The AdS/CFT correspondence continues to offer a tantalizing glimpse beyond, but each revealed structure only highlights how much remains obscured. These ‘pocket black holes’ – simplified models capturing fragments of a far more complex reality – are useful, certainly, but their very utility is a reminder of the limits of reduction. Sometimes matter behaves as if laughing at the laws constructed to contain it.

The presence of conical singularities demands further scrutiny. They are not merely technical difficulties to be smoothed over, but potential windows into the breakdown of the classical approximations underpinning these calculations. To truly understand their implications requires a descent into the abyss – increasingly sophisticated simulations, pushing the boundaries of computational power, and a willingness to confront the possibility that the dual field theories are far stranger than anticipated.

The real challenge lies not in building more elaborate wormholes, but in recognizing when the map dissolves. Each successful connection between geometry and quantum field theory is a temporary reprieve, a fleeting moment of clarity before the horizon reasserts itself. The pursuit isn’t about finding the answer, but learning to navigate the fundamental unknowability at the heart of existence.


Original article: https://arxiv.org/pdf/2512.24891.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2026-01-03 10:29