Particle Collisions Reveal New Entanglement Between Matter and Antimatter

João Barata and colleagues have performed the first real-time simulation of baryon scattering within a $(1+1)$-dimensional SU lattice gauge theory using tensor-network techniques. The simulation investigates collisions across sectors with varying baryon numbers, representing meson-meson, meson-baryon, and baryon-baryon interactions. Results at strong coupling show that some channels mimic established models, but the mixed baryon number sector exhibits novel behaviour, notably entanglement between colliding particles and differing propagation characteristics. The simulation characterises these complex processes through the use of local observables, entanglement entropy, and the information lattice, offering new insights into the dynamics of hadronic scattering. Real-time simulations demonstrate sustained entanglement in meson-baryon collisions across eighty Entanglement measures now reveal a previously unseen degree of correlation, increasing from isolated particle behaviour to sustained entanglement across 80 qubits during meson-baryon collisions. This represents the first instance of observing entanglement in real-time simulations of baryon scattering, a feat impossible with traditional computational methods limited by the strong coupling regime. Prior simulations, often reliant on Monte Carlo methods, were largely restricted to characterising static properties of hadrons or weakly interacting systems. This hindered a complete understanding of the dynamics of strongly coupled hadrons. The strong coupling regime, where perturbative calculations fail, necessitates non-perturbative approaches like those employed here. These advancements allow scientists to explore the complex interplay of forces within these particles with unprecedented detail. Tensor-network techniques, specifically designed to handle the exponential growth of Hilbert space dimensionality in quantum many-body systems, enabled the study of baryon number sectors B = 0, 1, and 2. The baryon number, a conserved quantity, dictates the number of quarks minus antiquarks; B = 0 corresponds to meson-meson interactions (quark-antiquark collisions), B = 1 to meson-baryon interactions (quark-antiquark and three-quark collisions), and B = 2 to baryon-baryon interactions (three-quark collisions). Revealing qualitatively new physics in the mixed B = 1 sector, where mesons and baryons become entangled, is a significant outcome. A slower wavepacket in meson-baryon collisions became spatially delocalized, extending across the simulation lattice, while the faster particle propagated predictably. This suggests a complex momentum transfer during the interaction. This differing behaviour is crucial for understanding energy dissipation and particle formation. Detailed analysis using entanglement entropy, a measure of quantum entanglement quantifying the amount of information needed to describe one subsystem given knowledge of another, and a novel ‘information lattice’ diagnostic confirmed that the meson and baryon did not simply bounce off each other. Instead, they formed a single, entangled collective state after impact. The information lattice, a measure of multi-body correlations beyond pairwise entanglement, revealed no new internal correlation lengths forming within this entangled state. This suggests it isn’t a tightly bound structure like a resonance. This implies the entanglement is transient, arising from the collision dynamics rather than a stable bound state. Calculations were performed on a system of 60 qubits, with a maximum bond dimension of 80 to ensure accuracy; the bond dimension controls the amount of entanglement that can be represented within the tensor network, and a higher value generally leads to more accurate results but also increased computational cost. Real-time hadron collision simulation reveals challenges for three-dimensional quantum entanglement Probing the behaviour of hadrons, particles like protons and neutrons, during collisions is essential for understanding the fundamental forces governing the Standard Model of particle physics. This work offers an important step forward by simulating these interactions in real-time, a feat previously hampered by the computational demands of strong coupling physics. The traditional approach of discretizing spacetime on a lattice introduces numerical challenges, particularly in real-time evolution where maintaining stability and unitarity is paramount. However, success in modelling entanglement within this simplified $(1+1)$-dimensional framework raises a key tension: can these observed quantum correlations be sustained, or even emerge, when scaling up to the far more complex and computationally intensive three-dimensional world mirroring reality. The increased dimensionality significantly expands the Hilbert space, making tensor-network simulations exponentially more demanding. The simulations quantified the number of quarks minus antiquarks across different baryon numbers, revealing that some interactions mirrored existing theoretical predictions derived from chiral perturbation theory, while others displayed unexpected behaviour. This simulation marks the first observation of real-time hadronic scattering within a simplified theoretical framework. Tensor networks represent quantum states as interconnected arrays, allowing for the modelling of collisions without the exponential scaling issues of traditional methods. The gaugeless Hamiltonian formulation, employed in this study, simplifies the calculations by removing the need to explicitly solve for the gauge fields, focusing instead on the dynamics of the fermionic degrees of freedom. Collisions involving both mesons and baryons resulted in entanglement between the particles, with wavepackets becoming spatially separated during impact, mirroring behaviour seen in simpler models, and providing insight into the limitations of current computational power when applied to more realistic scenarios. The observed spatial separation suggests a transfer of momentum and energy during the collision, influencing the subsequent trajectories of the particles. The findings highlight the potential of tensor-network techniques as a powerful tool for investigating non-perturbative quantum field theories. Future research will focus on extending these simulations to higher dimensions and incorporating more realistic interactions, potentially including the effects of quark masses and different gauge groups. Understanding the fate of entanglement in these more complex scenarios is crucial for developing a complete picture of hadronic dynamics and the emergence of confinement, the phenomenon that prevents isolated quarks from being observed in nature. The ability to accurately simulate these processes could also have implications for understanding the quark-gluon plasma, a state of matter believed to have existed shortly after the Big Bang.

This research demonstrated real-time observation of hadronic scattering using a $(1+1)$-dimensional SU(2) lattice gauge theory and tensor-network techniques. The study revealed that collisions between mesons and baryons lead to entanglement, causing wavepackets to become spatially separated, a behaviour previously observed in simpler models. Researchers investigated baryon numbers of 0, 1, and 2, finding predominantly elastic dynamics in the 0 and 2 channels. The authors intend to extend these simulations to higher dimensions and incorporate more realistic interactions to further explore the dynamics of entanglement and confinement. 👉 More information 🗞 Quantum simulation of baryon scattering in SU(2) lattice gauge theory 🧠 ArXiv: https://arxiv.org/abs/2604.06716 Tags: