Entanglement properties of photon-magnon crystal from nonlinear perspective

Abstract

Quantifying the entanglement between two continuous bosonic modes, such as magnons and photons, is not trivial. The logarithmic negativity, calculated through the quantum Langevin equations is subjected to thermal noise. However this method requires further approximation. The phase space of a generic nonlinear system contains topologically different regions, and the steady state may correspond to the different types of fixed points, such as Saddle Points, Stable or unstable Spirals, and Nodes. In the present work, we propose a new procedure. Namely, we derived the complete set of nonlinear equations, which includes equations for the magnon and photon number operators and phases. We show that not only number operators but also phases are important for exploring the character of the fixed point, and magnon-photon entanglement. We showed that methods of the qualitative theory of nonlinear differential equations are also relevant for photon-magnon entanglement problems. Our main finding is that entanglement is not defined in the Saddle Point region. On the other hand, the maximum of the entanglement corresponds to the region near the border between the Stable node and Stable spiral regions. Our approach is quite general. However, we did calculations for a particular system: photon-magnon crystal based on the yttrium iron garnet (YIG) film with the periodic air holes drilled in the film. Our interest focuses on magnons with a particular wavelength and frequency corresponding to the magnon condensate. Those magnons couple strongly with the photons of similar frequency. We discuss in detail the interaction between magnons and photons originating from the magneto-electric coupling and the effective Dzyaloshinskii-Moriya interaction. We show that this interaction is responsible for the robust photon-magnon entanglement in the system.

This article has been accepted for publication in Physica D: Nonlinear Phenomena

References in corpus (18)

• Strongly coupled magnons and cavity microwave photons
• Hybridizing ferromagnetic magnons and microwave photons in the quantum limit
• Entanglement in continuous variable systems: Recent advances and current perspectives
• Mechanical Bistability in Kerr-modified Cavity Magnomechanics
• Mesoscopic physics of nanomechanical systems
• Enhancement of magnon-photon-phonon entanglement in a cavity magnomechanics with coherent feedback loop
• Dispersive read-out of ferromagnetic resonance for strongly coupled magnons and microwave photons
• Steady entangled-state generation via cross-Kerr effect in a ferrimagnetic crystal
• Detection sensitivity enhancement of magnon Kerr nonlinearity in cavity magnonics induced by coherent perfect absorption
• Nonreciprocal high-order sidebands induced by magnon Kerr nonlinearity
• Positive-Negative Birefringence in Multiferroic Layered Metasurfaces
• Creation and Amplification of Electro-Magnon Solitons by Electric Field in Nanostructured Multiferroics
• Design of an optomagnonic crystal: towards optimal magnon-photon mode matching at the microscale
• Bistability in dissipatively coupled cavity magnonics
• Many-body localization phase in a spin-driven chiral multiferroic chain
• Critical metrology of minimally accessible anisotropic spin chains
• Prethermal Floquet time crystals in chiral multiferroic chains and applications as quantum sensors of AC fields
• Anisotropy-assisted magnon condensation in ferromagnetic thin films