BLFQ Calculates Entanglement in Charmonium and Bottomonium

Wenyu Zhang and colleagues have demonstrated a surprising connection between quantum entanglement and measurable properties within heavy quarkonium particles. The study reveals that for spin-0 quarkonia, the calculated von Neumann entropy, a measure of entanglement, reduces to the Shannon entropy of the unpolarized transverse momentum dependent parton distribution, up to constant color and spin contributions. Researchers further derived the explicit polarization dependence of the entropy and connected it to polarized and tensor-polarized parton distributions. Evaluating entanglement entropy for both charmonium and bottomonium states using basis light-front quantization, the work shows a pronounced sensitivity to the polarization of these vector mesons, establishing entanglement entropy as a novel way to probe nonperturbative quarkonium structure. Ultimately, these results forge a direct link between quantum information measures and partonic observables. Quarkonium Entanglement via Light-Front Hamiltonian Framework A surprising link between quantum entanglement and the internal structure of heavy particles known as quarkonia has emerged from new theoretical work.

Researchers Wenyu Zhang of China and colleagues are demonstrating that the degree to which a quark and antiquark are quantumly linked within these particles directly correlates with measurable properties of their constituent parts, offering a novel way to probe the strong force. The study, leveraging a nonperturbative light-front Hamiltonian framework, establishes entanglement entropy as a potential new tool for understanding the complex dynamics governing these bound states.

The team extended this analysis to spin-1 quarkonia, deriving the explicit polarization dependence of the entropy and connecting it to polarized and tensor-polarized TMDs. This finding suggests that the entanglement within these particles isn’t static, but actively responds to changes in their polarization state. This change is linked to specific, measurable polarized TMDs, implying that entanglement measurements could serve as a sensitive probe of internal polarization states. They resolved the infrared parameter, allowing for more accurate predictions and strengthening the theoretical foundation of their approach. Spin-0 & Spin-1 Quarkonia and TMD Entropy Relationships The exploration of quarkonium structure has entered a new phase, leveraging tools from quantum information science to reveal connections previously obscured by traditional methods.

Researchers Wenyu Zhang, Yiyu Zhou, Yang Li, and Qun Wang explained to the author that they are moving beyond simply characterizing parton distributions to quantifying the entanglement inherent within these heavy quark-antiquark bound states, offering a more complete picture of their non-perturbative dynamics. This approach doesn’t merely describe the probability of finding a parton within a hadron; it delves into the quantum correlations that define its existence. This isn’t a simple correlation; the entanglement actively responds to changes in the meson’s polarization state. The study resolves the infrared parameter by matching the momentum-space entropy to a harmonic-oscillator representation. The implications extend beyond heavy quarkonia, hinting at a broader framework for understanding entanglement’s role in all hadronic systems. Researchers are increasingly leveraging quantum information science to dissect the complex internal structure of hadrons, and a team including Wenyu Zhang, Yiyu Zhou, Yang Li, and Qun Wang is developing a novel approach to quantify entanglement within heavy quarkonium, particles composed of heavy quarks and antiquarks.

The team’s investigation centers on charmonium and bottomonium states, utilizing a nonperturbative light-front Hamiltonian framework to analyze quark-antiquark entanglement. This is not merely a mathematical convenience, but suggests a fundamental connection between a complex quantum property and a more readily measurable quantity. This sensitivity was observed in both charmonium and bottomonium, indicating a consistent entanglement behavior across these heavy quarkonia.

The team employed basis light-front quantization (BLFQ) to evaluate the entanglement entropy for charmonium and bottomonium states, a technique that allows for the construction of light-front wave functions. This approach, they note, offers a rigorous field-theoretic definition of partons and facilitates analytic expressions for the entanglement entropy. They resolved the infrared parameter, establishing a connection between the momentum-space entropy and a harmonic-oscillator representation. Understanding the internal dynamics of particles like charmonium and bottomonium requires navigating the complexities of quantum chromodynamics, or QCD, in its non-perturbative regime. Recent work is refining calculations of entanglement within these heavy quarkonia, not merely as a theoretical exercise, but as a pathway to more accurately describe their fundamental structure and measurable properties. A key advancement lies in the ability to resolve the infrared parameter by matching the momentum-space entropy to a harmonic-oscillator representation. This parameter was resolved within the context of their work. This allows for analytic expressions, moving beyond treating partons as simple probabilistic densities. This work signifies a shift towards utilizing quantum information tools to unlock deeper insights into the fundamental building blocks of matter and their intricate interactions. The conventional picture of hadrons, like protons and neutrons, as simply collections of quarks and gluons is increasingly challenged by the realization that quantum entanglement plays a fundamental role in their structure. This work demonstrates a pronounced sensitivity of entanglement entropy to the polarization of vector mesons, suggesting that entanglement could be used as a probe for polarization states within these particles.

The team constructed a reduced density matrix of the quark subsystem and computed the associated von Neumann entropy, establishing a connection between spin polarization, the entanglement structure, and TMDs. Source: https://arxiv.org/abs/2607.24068 Stay currentSee today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals. Tags: