[Paper Review] Chromodynamics of photons in an artificial non-Abelian magnetic Yang-Mills field

Antonio Fieramosca, Laura Polimeno+13 more|arXiv (Cornell University)|Dec 20, 2019

Topological Materials and Phenomena1 references10 citations

TL;DR

This study experimentally realizes an artificial non-Abelian Yang-Mills gauge field for cavity photons in a 2D perovskite microcavity, using strong spin-orbit coupling to induce a SU(2) gauge field that mimics the chromodynamics of quarks. The system demonstrates curved trajectories and spin precession in exciton-polariton wave packets, directly observing SU(2) chromodynamics equations in real space, offering a photonic simulator for quark-gluon dynamics with direct experimental access to spin and trajectory evolution.

ABSTRACT

Artificial gauge fields, simulating real phenomenologies that unfold in a vast variety of systems, offer extraordinary possibilities to study extreme physical effects in many different environments, from high energy physics to quantum mechanics and cosmology. They are also at the heart of topological physics. Here, exploiting a strongly anisotropic material under strong coupling regime, we experimentally synthesize a Yang-Mills non-Abelian gauge field acting on an exciton-polariton quantum flow like a magnetic field. We observe experimentally the corresponding curved trajectories and spin precession. This motion follows chromodynamics equations which normally describe the quarks strong interactions and their color. Our work therefore opens exciting perspectives of simulating quark-gluon dynamics using highly flexible photonic simulators. It makes of sub-atomic physics a potential new playground to apply topological physics concepts.

Motivation & Objective

• To realize an artificial non-Abelian gauge field for photons in a solid-state platform.
• To simulate quark-like chromodynamics using exciton-polaritons in a strongly coupled system.
• To experimentally observe the effects of a Yang-Mills magnetic field on spatial trajectories and spin evolution.
• To provide a direct, accessible analog of quantum chromodynamics using photonic systems.

Proposed method

• Engineering a 2D hybrid organic-inorganic perovskite microcavity with strong spin-orbit coupling via birefringence.
• Utilizing the Rashba-Dresselhaus spin-orbit coupling in a strongly coupled exciton-polariton system to generate a non-Abelian SU(2) gauge potential.
• Measuring wave packet trajectories and spin textures via polarization-resolved emission imaging.
• Applying the Yang-Mills chromodynamics equations to model the coupled spatial and spin dynamics.
• Comparing experimental results with simulations based on the SU(2) chromodynamics equations.
• Using a defect potential to probe the transverse force and spin precession effects in the non-Abelian field.

Experimental results

Research questions

• RQ1 Can a non-Abelian Yang-Mills gauge field be experimentally synthesized for photons in a solid-state system?
• RQ2 How do the spatial trajectories and spin precession of exciton-polaritons respond to an artificial non-Abelian gauge field?
• RQ3 To what extent can the observed dynamics be described by SU(2) chromodynamics equations?
• RQ4 Can the system serve as a photonic simulator for quark-gluon dynamics with direct experimental observability?
• RQ5 What distinguishes the non-Abelian Yang-Mills force from Abelian emergent gauge effects like the anomalous Hall effect?

Key findings

• The system exhibits curved trajectories of exciton-polariton wave packets due to a transverse Yang-Mills force, directly observed in real space.
• Spin precession of the polaritons is measured, with s3 component oscillations confirming the non-Abelian gauge coupling.
• The experimental trajectories and spin textures match simulations based on the SU(2) chromodynamics equations.
• A defect potential induces a convergent flow downstream, with opposite spin currents above and below, leading to transverse forces that shape the density profile.
• The observed dynamics are distinct from anomalous Hall effects, as they arise from real-space non-Abelian gauge fields rather than Berry curvature in momentum space.
• The system provides a fully solvable, accessible analog of quantum chromodynamics, enabling direct measurement of particle trajectories and spin orientation.