Gravity Links Separate Objects Via Quantum Entanglement, Research Confirms

Researchers are increasingly focused on understanding how gravity impacts quantum entanglement, a fundamental problem in modern physics. Hazhir Dolatkhah from Farhangian University, Shahriar Salimi from University of Kurdistan, and Soroush Haseli from Urmia University of Technology, alongside their colleagues, present a novel analysis of gravitationally-induced entanglement using resource theory. Their work demonstrates that gravitational interaction functions as a channel which converts local coherence, present within individual systems, into shared, non-local entanglement between two spatially separated masses. By establishing precise analytical relationships, the team directly links the loss of local coherence to the creation of entanglement, validated through numerical simulations. This research clarifies the mechanism behind this conversion, positioning gravity as a genuine coherence-to-entanglement channel and providing a crucial theoretical foundation for future experimental verification.

Gravity mediates coherence-entanglement conversion in macroscopic systems

Researchers have demonstrated that gravity can directly convert local quantum coherence into shared entanglement between two masses. This work clarifies a fundamental mechanism underlying the quantum nature of gravity, establishing gravity as a unique coherence-to-entanglement conversion channel. Building upon previous interferometric work by Bose et al., the study reveals that gravitational interaction functions as a unitary process, effectively redistributing quantum resources between spatially superposed masses rather than destroying them.

Specifically, the research demonstrates that entanglement arises from the coherent conversion of local coherence, initially present within each mass, into non-local correlations. Through analytical calculations and numerical simulations, scientists derived exact complementarity relations that quantify this conversion, directly linking the decay of local coherence to the growth of entanglement.

These findings establish that initial coherence is not merely a prerequisite for entanglement generation but also fundamentally limits its maximum achievable degree; maximal entanglement necessitates initial maximal coherence. The investigation centres on two neutral test masses, each prepared in a superposition of spatially separated locations.

The gravitational interaction between these masses, governed by their mutual gravitational attraction, induces phase evolution that creates correlations between their quantum states. This process transforms the initial spatial superposition of each mass into an entangled state, where the properties of one mass are intrinsically linked to the other.

The resulting two-qubit system, encoding information in the spatial degrees of freedom, exhibits entanglement contingent upon specific phase differences arising from the gravitational interaction. Furthermore, the study utilizes the framework of quantum resource theory to analyse this process. By defining coherence as a quantum resource and identifying gravity as a coherence-preserving operation, researchers provide a refined interpretive basis for future experimental tests designed to probe the quantum nature of gravity. This work not only clarifies the mechanism of entanglement generation but also establishes a quantitative relationship between initial coherence and the resulting entanglement, offering a powerful tool for understanding and manipulating quantum correlations in gravitational systems.

Quantifying coherence to entanglement conversion via gravitational interaction

Researchers investigated the mechanism of gravitationally-induced entanglement by employing the framework of resource theory, building upon prior work by Bose et al. specifically examining the redistribution of resources between spatially superposed masses. The study demonstrated that gravitational interaction functions as a unitary channel, coherently converting local coherence initially present within each subsystem into shared, non-local correlations.

Exact analytical complementarity relations were derived to quantify this conversion, directly linking the decay of local coherence to the growth of entanglement, and these findings were validated through numerical simulations. Central to the methodology was the precise characterisation of coherence and entanglement dynamics.

The research established that initial coherence is a necessary condition for entanglement generation, with the degree of initial coherence directly bounding the maximum achievable entanglement. This work clarified that maximal entanglement necessitates initial maximal coherence, providing a fundamental constraint on the process.

The analytical complementarity relations derived offer a mathematical description of the trade-off between local coherence and shared entanglement, allowing for precise prediction of entanglement growth based on initial coherence levels. Furthermore, the study’s approach involved a detailed analysis of bipartite entanglement originating from the coherent conversion of local coherence.

This conversion was not merely observed but quantified through the derived complementarity relations, enabling a refined understanding of gravity as a coherence-to-entanglement conversion channel. The methodology’s strength lies in its ability to connect a measurable quantity, local coherence, to the emergence of a quantum correlation, entanglement, under the influence of gravity, offering a basis for future experimental verification of quantum gravity effects.

Gravitational coherence-to-entanglement conversion and complementarity relations

Researchers demonstrate that gravitational interaction functions as a unitary channel, dynamically redistributing resources between two spatially superposed masses. Specifically, the work establishes that bipartite entanglement arises from the coherent conversion of local coherence initially present within each subsystem into shared, non-local correlations.

Exact, analytical complementarity relations were derived to quantify this conversion, linking the decay of local coherence directly to the growth of entanglement, and these findings are supported by numerical simulations. This study clarifies the underlying mechanism of entanglement generation via gravity and defines gravity as a coherence-to-entanglement conversion channel.

Initial coherence is demonstrated to be a necessary condition for entanglement generation, with the degree of initial coherence bounding the maximum achievable entanglement. Maximal entanglement is attainable only when initial coherence reaches a maximal state. The gravitational interaction is shown to be a coherence-preserving operation, meaning the total quantum coherence of the system remains constant throughout gravitational transformation.

Consideration was given to two neutral test masses, A and B, with masses mA and mB respectively, becoming entangled through gravitational interaction. Each mass was initially prepared in a superposition state described by |ψ⟩A = 1/√2(|L⟩A + |R⟩A) and |ψ⟩B = 1/√2(|L⟩B + |R⟩B), resulting in an initial joint state of |ψ⟩AB = 1/√2(|L⟩A + |R⟩A) ⊗ 1/√2(|L⟩B + |R⟩B).

Following gravitational interaction over a time τ, the state evolves to |ψ(τ)⟩AB = eiφ/2 (|LL⟩AB + ei∆φLR|LR⟩AB + ei∆φRL|RL⟩AB + |RR⟩AB), where ∆φRL = φRL − φ, ∆φLR = φLR − φ, and φRL ∼ Gm1m2τ/h(d − ∆x), φLR ∼ Gm1m2τ/h(d + ∆x), and φ ∼ Gm1m2τ/hd. Entanglement exists between the qubits when the states 1/√2(|L⟩B + ei∆φLR|R⟩B) and 1/√2(ei∆φRL|L⟩B + |R⟩B) are not identical, occurring when ∆φLR + ∆φRL = 2nπ, where n is an integer. This non-factorizable state confirms entanglement, and the degree of entanglement is quantitatively determined and bounded by the initial coherence of the system.

Coherence depletion directly quantifies entanglement generation via gravitational interaction

Gravitational interaction functions as a mechanism for converting local coherence into shared entanglement between spatially separated masses. Researchers have demonstrated that when two test masses are initially prepared in superpositions, their gravitational interaction leads to the generation of bipartite entanglement.

This entanglement arises from a coherent conversion of the initial local coherence present in each mass into non-local correlations. Specifically, the study establishes exact analytical relationships quantifying this coherence-to-entanglement conversion. Numerical simulations corroborate these findings, demonstrating a direct link between the decay of local coherence and the growth of entanglement.

Initial coherence is identified as a necessary condition for entanglement generation, and its magnitude directly bounds the maximum achievable entanglement; maximal entanglement necessitates maximal initial coherence. These results clarify the underlying physical process and position gravitational interaction as a coherence-to-entanglement conversion channel, providing a basis for future experimental verification.

The authors acknowledge that the analysis relies on specific simplifications, such as neglecting short-range interactions like the Casimir-Polder force, which may become relevant under different conditions. Future research could explore the implications of these neglected effects and investigate the robustness of the observed coherence-to-entanglement conversion in more complex scenarios. Further investigation into the practical limitations of generating and maintaining the necessary initial coherence for observable entanglement is also warranted, alongside the development of experimental setups designed to test these theoretical predictions.