Entangled Time: A New View of Quantum Reality

Author: Denis Avetisyan

A novel framework proposes that time isn’t a fundamental constant, but emerges from the quantum relationships between observers and the universe itself.

Local subsystems become entangled with a global clock, yet variations in spacetime geometry and relative motion modulate the rate of correlation, resulting in a distinct, observer-dependent flow of time that replicates relativistic time dilation within a quantum-relational framework.

This review presents a relational, emergent time framework unifying quantum mechanics and general relativity through entanglement, time dilation, and FLRW cosmology.

The persistent tension between quantum mechanics and general relativity stems, in part, from the assumption of a fundamental, universal time. This is addressed in ‘Relational Emergent Time for Quantum System: A Multi-Observer, Gravitational, and Cosmological Framework’, which proposes that temporal structure isn’t pre-existing but emerges from correlations within a global quantum state, effectively making time relational and observer-dependent. The framework successfully unifies diverse physical regimes – from relativistic motion and gravitational effects to cosmological expansion – by grounding time in the entanglement between subsystems and an overarching global clock. Could this relational view of time offer new avenues for understanding quantum gravity and the foundations of temporal physics, and potentially reveal measurable deviations from standard quantum evolution in highly entangled systems?

The Illusion of Absolute Time

For centuries, physics has operated under the assumption of an absolute, universal time – a steady, unchanging backdrop against which all events unfold. This notion, deeply ingrained in both Newtonian mechanics and early formulations of relativity, presents significant hurdles when attempting to reconcile gravity with quantum mechanics. The primary difficulty arises from the inherent conflict between a fixed temporal framework and the probabilistic, dynamic nature of quantum states. Attempts to quantize gravity, such as string theory and loop quantum gravity, repeatedly encounter mathematical inconsistencies and conceptual paradoxes precisely because they attempt to impose a quantum description onto a classically defined, absolute time. This foundational reliance on a pre-existing time dimension creates issues when describing the very origins of the universe – if time itself emerged with the universe, then a pre-existing time against which to describe its birth becomes logically problematic, suggesting the need for a radically different approach to understanding the cosmos.

The conventional understanding of physics rests upon time as a fundamental parameter against which change occurs, but the Hamiltonian Constraint, arising from the equations of quantum gravity, proposes a radically different picture. This constraint, essentially a consequence of demanding a consistent quantum description of gravity, implies the universe may not evolve through time at its most fundamental level. Instead, the universe is potentially described by a single, unchanging quantum state – a “Global Quantum State” – existing outside of temporal progression. This isn’t to say time doesn’t exist; rather, it suggests time is not a fundamental building block of reality, but an emergent property arising from relationships within this static, timeless state. The Wheeler-DeWitt equation, a key component of this framework, mathematically expresses this timelessness, treating time as merely a parameter used in calculation, not as a dynamic variable governing the universe’s behavior. This perspective necessitates a re-evaluation of how change and causality operate, suggesting they are illusory from a truly fundamental perspective, and that the perception of time is a consequence of how observers experience correlations within this unchanging quantum state.

If the universe operates at its most fundamental level without the need for time, the experienced flow from past to future becomes a profound puzzle. Current research explores the possibility that time isn’t a pre-existing dimension, but rather an emergent property arising from the relationships between the universe’s constituent parts. One leading hypothesis suggests that observers within the universe perceive time through correlations – changes in these correlations, or the ‘quantum entanglement’ between different regions of space, could be interpreted as the passage of time. Essentially, the universe may be a static, timeless ‘block’ described by a global quantum state, and the sensation of temporal flow is a consequence of how observers, themselves embedded within this block, register changes in these internal correlations. This perspective shifts the focus from a universe in time to a universe generating time through the dynamics of its interconnectedness, potentially resolving the conflicts between quantum mechanics and general relativity by eliminating time as a fundamental ingredient.

The universe can be modeled as a stationary, high-dimensional hypercube where observer-dependent time emerges from one-dimensional slices selected by their internal clock and influenced by relativistic effects.

Relational Time: A Universe Woven from Correlations

The Emergent Time Framework challenges the conventional understanding of time as a fundamental dimension, positing instead that it arises from the relationships between physical subsystems and a universal reference, termed the Global Clock. This framework doesn’t require a pre-existing temporal background; instead, time is considered a derived property resulting from correlations. Specifically, the temporal order and duration are not absolute quantities, but are defined by how a subsystem’s internal dynamics correlate with the state of the Global Clock. The degree of correlation between a subsystem and the Global Clock determines the subsystem’s experienced “time,” meaning that time is not uniform throughout the universe, but is relative to each system’s interactions and entanglement with the universal clock.

Hilbert Space Decomposition, as applied within the Emergent Time framework, mathematically separates the total Hilbert space, $H_{total}$, of the universe into two subspaces: $H_{clock}$ representing the degrees of freedom defining a global clock, and $H_{subsystem}$ encompassing all other degrees of freedom constituting subsystems. This decomposition is not physical separation, but a mathematical construct enabling the definition of a relational time variable. Any state vector $|\psi\rangle \in H_{total}$ can be expressed as a tensor product of states in these subspaces: $|\psi\rangle = |c\rangle \otimes |s\rangle$, where $|c\rangle \in H_{clock}$ and $|s\rangle \in H_{subsystem}$. The correlations between $|c\rangle$ and $|s\rangle$ then define the subsystem’s internal time, effectively treating the clock degrees of freedom as a reference frame against which the subsystem’s evolution is measured.

Within the Emergent Time framework, temporal relationships are not defined by a universal, absolute time, but are instead relational and subsystem-specific. Each subsystem possesses an internal clock, representing its intrinsic rate of change. Time, as experienced by that subsystem, is then determined by the correlations between its internal clock and the degrees of freedom of the universe as a whole. This means that different subsystems will experience time at different rates depending on the strength and nature of these correlations, leading to a fundamentally relational view of temporal evolution. The perceived duration of events is thus not a measure against a fixed external timeline, but a function of the subsystem’s internal dynamics and its entanglement with the global system, quantified through Hilbert Space Decomposition.

This plot demonstrates that, as entanglement between a clock and subsystem increases, local coherence of the subsystem decays monotonically, consistent with the standard model.

The Quantum Dance of Emergent Time

The dynamics of a quantum subsystem are not governed by a time-independent Hamiltonian, but by an effective Schrödinger evolution that is conditional on the state of a designated global clock system. This is formally described using a Conditional Quantum State, $ \rho_{subsystem|clock} $, representing the reduced density matrix of the subsystem given a specific state of the clock. The evolution of this conditional state is then given by a master equation derived from the interaction between the subsystem and the clock, effectively treating the clock state as a parameter defining the dynamics. This approach contrasts with standard quantum mechanics where time is an external parameter; here, the clock’s quantum state directly influences and determines the subsystem’s evolution, establishing a relational dynamic.

The observed temporal evolution of a quantum subsystem, described by Effective Schrödinger Evolution, does not originate from propagation within an externally defined, absolute time parameter. Instead, this dynamic is an emergent phenomenon. It arises directly from the relational structure between the subsystem and a global clock; the subsystem’s evolution is conditional on the state of the clock. This means the ‘time’ governing the subsystem is not a pre-existing coordinate but is defined by the correlations established through quantum entanglement. Consequently, the effective Schrödinger equation is not operating in time, but rather describes how the subsystem’s state changes relative to the state of the clock, effectively constructing a relational timescale.

The emergent temporal dynamic observed in subsystems is directly attributable to the entanglement shared between the subsystem and the global clock. This isn’t simply a correlation in time, but rather the foundational mechanism of time’s manifestation for that subsystem. Specifically, the quantum correlations-described by the density matrix $\rho_{CS}$ where C represents the clock and S the subsystem-define the conditional state and, consequently, the effective Schrödinger evolution. Changes in the clock state induce predictable changes in the subsystem’s state, and these correlations, measurable through quantum state tomography, establish the relational structure that gives rise to the perception of temporal progression within the subsystem. The stronger the entanglement-quantified by measures such as entanglement entropy-the more defined and predictable the emergent temporal behavior.

Spacetime’s Influence: Time as a Relational Landscape

The notion of time, within the Emergent Time Framework, isn’t absolute but rather a consequence of underlying correlations, and thus susceptible to external influences like relativistic effects. This model posits that the rate at which emergent time flows is directly impacted by both Special Relativity and the expansion of the universe. Specifically, velocities approaching the speed of light, as described by Special Relativity, cause a measurable slowing of emergent time, mirroring the phenomenon of time dilation. Simultaneously, the accelerating expansion of the cosmos introduces a similar suppression of the emergent temporal flow, particularly evident in regions approaching cosmological horizons. These aren’t merely analogous effects; the framework predicts these relativistic distortions as inherent features of how time emerges from the fundamental correlations, effectively weaving spacetime dynamics directly into the fabric of temporality itself. Consequently, the framework doesn’t simply accommodate relativistic predictions – it necessitates them as a natural outcome of its core principles, suggesting a deep connection between the geometry of spacetime and the experience of time’s passage.

The Emergent Time Framework doesn’t merely allow for gravitational time dilation – it actively reproduces the predictions of General Relativity concerning this phenomenon. This consistency arises from the framework’s inherent connection between the global correlations defining emergent time and the curvature of spacetime. Specifically, the rate at which emergent time flows is demonstrably altered by gravitational potential; stronger gravitational fields result in a slower flow of emergent time, precisely mirroring the well-established effects observed in experiments and astrophysical settings. Crucially, this isn’t a forced fit – the model accurately predicts gravitational time dilation across a range of spacetime geometries, from the weak-field approximations relevant to Earth-bound experiments to the strong-field regimes near black holes, validating its robustness and offering a new perspective on the relationship between time and gravity.

Investigations within the Emergent Time Framework reveal a compelling consistency with established principles of Special Relativity, specifically concerning kinematic time dilation. The model accurately predicts that time intervals will differ for observers in relative motion, aligning with the well-known Lorentz factor and its impact on temporal measurements. Furthermore, the framework extends these predictions to cosmological scales, demonstrating a suppressed flow of emergent time consistent with the presence of event horizons in accelerated expansion. This suppression isn’t a deviation from relativistic principles, but rather a natural consequence of considering time as arising from global correlations – effectively, the further an observer is, or the faster they recede, the weaker the correlations and the slower time appears to flow from a global perspective, mirroring the behavior predicted by horizon effects and the limitations on observable information.

The sensation of time’s passage, known as proper time, is fundamentally linked to, yet separate from, the emergent time established by correlations across a system. While proper time is locally defined by an observer’s experience – the ticking of a watch, for instance – emergent time arises from the global relationships between all constituent parts. This distinction suggests that proper time represents a specific, localized ‘slice’ of the more fundamental, globally-defined emergent time. Consequently, the rate at which proper time flows can be influenced by the overall dynamics of the system, including relativistic effects and cosmological expansion, which alter the correlations giving rise to emergent time. This implies that an observer’s individual experience of time isn’t absolute, but rather a consequence of their position within a larger, interconnected temporal structure, where $t_{proper}$ is a function of the globally-defined emergent time $t_{emergent}$.

Beyond the Standard Model: A Universe Woven from Relationships

The current framework represents a significant advancement over the foundational Page-Wootters mechanism for understanding time, not by replacing it, but by elaborating on its core principles. While the Page-Wootters approach initially posited that time emerges from correlations between static universes, this new model introduces a more nuanced perspective, allowing for a dynamic interplay of these correlations. It moves beyond a simple binary relationship, suggesting that time isn’t merely defined by the absence of correlation, but rather exists as a spectrum of relational degrees of freedom. This expanded view allows for the possibility of internal time within universes, and crucially, offers a potential resolution to the problem of time in quantum gravity by framing it not as something to be fixed, but as a property that emerges from the relationships between systems – a relational tapestry woven from the interactions of quantum states.

Investigations into emergent time offer potentially revolutionary insights into the most extreme environments in the universe, particularly within quantum cosmology and the interiors of black holes. Current cosmological models often struggle to reconcile general relativity with quantum mechanics at the very beginning of the universe; a framework where time itself arises from relational correlations could provide a novel approach to understanding the initial conditions and evolution of the cosmos. Similarly, the singularity at the heart of a black hole, where classical physics breaks down, may be resolved by recognizing that time, as traditionally understood, is not a fundamental property of spacetime in these regions. Instead, time could emerge from the entanglement of quantum degrees of freedom, offering a path toward a consistent quantum description of gravity and the information paradox. These avenues of research suggest that the nature of time is not merely a philosophical question, but a crucial component in resolving some of the deepest mysteries in physics.

The conventional understanding of time as a universal, absolute entity may be obscuring fundamental aspects of the universe’s architecture. Current theoretical work suggests that time isn’t a pre-existing dimension, but rather emerges from the correlations between physical systems. This perspective, moving away from a singular timeline, proposes that time is intrinsically linked to relationships – an event’s temporal definition is established by its connections to other events and the information exchanged between them. Consequently, a universe understood through relational time may resolve inconsistencies arising from attempts to reconcile general relativity and quantum mechanics, offering new avenues for exploring quantum cosmology and the enigmatic interiors of black holes. The very fabric of reality, therefore, could be less about ‘when’ things happen and more about how things are connected, potentially revealing a deeper, more unified structure underlying the cosmos.

The exploration of time as an emergent property, rather than a pre-existing dimension, echoes a deeper principle of complex systems. This research posits that time arises from the entanglement between subsystems and a global clock, a framework where relationality dictates perception. As Max Planck observed, “Anyone who is not convinced that quantum mechanics is strange enough should not be convinced at all.” This sentiment applies to the framework presented; the universe doesn’t require a central timekeeper, but instead generates the experience of time through interconnectedness. The study reinforces the idea that control is an illusion; influence – the entanglement driving emergent time – is the fundamental reality, aligning with the observation that order doesn’t need architects, but emerges from local rules.

The Horizon of Moments

The proposition that time itself is not a fundamental constituent of reality, but rather an emergent property of relational quantum mechanics, shifts the focus from measuring the universe to observing its inherent correlations. This framework, while elegantly uniting quantum mechanics and general relativity through entanglement and a global clock, does not erase the difficulty of defining ‘global’ within a dynamically evolving cosmos. The very notion of a universal clock, even relational, begs the question of its origins and stability across cosmological timescales-a question not fully addressed. The effect of the whole is not always evident from the parts.

Future work will likely center on refining the mathematical formalism to account for more complex cosmological scenarios, including the potential for time’s varying rates of emergence in regions of extreme gravitational curvature. A crucial test will be exploring how this relational emergent time interacts with quantum field theory, particularly in the context of particle creation and annihilation. The search for observational signatures-however subtle-that deviate from traditional notions of absolute time remains a daunting, but necessary, endeavor.

Perhaps the most profound implication lies not in solving existing paradoxes, but in accepting the inherent limitations of seeking a complete, objective description of reality. Sometimes it’s better to observe than intervene. The universe, after all, doesn’t require justification; it simply is, and its unfolding is a testament to the power of local rules giving rise to global complexity.

Original article: https://arxiv.org/pdf/2512.15789.pdf

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