Strong quantum interactions prevent quasiparticle decay

Abstract

Quantum states of matter---such as solids, magnets and topological phases---typically exhibit collective excitations---phonons, magnons, anyons. These involve the motion of many particles in the system, yet, remarkably, act like a single emergent entity---a quasiparticle. Known to be long-lived at the lowest energies, common wisdom says that quasiparticles become unstable when they encounter the inevitable continuum of many-particle excited states at high energies. Whilst correct for weak interactions, we show that this is far from the whole story: strong interactions generically stabilise quasiparticles by pushing them out of the continuum. This general mechanism is straightforwardly illustrated in an exactly solvable model. Using state-of-the-art numerics, we find it at work also in the spin-$\frac{1}{2}$ triangular lattice Heisenberg antiferromagnet (TLHAF) near the isotropic point---this is surprising given the common expectation of magnon decay in this paradigmatic frustrated magnet. Turning to existing experimental data, we identify the detailed phenomenology of avoided decay in the TLHAF material Ba${}_3$CoSb${}_2$O${}_9$, and even in liquid helium---one of the earliest instances of quasiparticle decay. Our work unifies various phenomena above the universal low-energy regime in a comprehensive description. This broadens our window of understanding of many-body excitations, and provides a new perspective for controlling and stabilising quantum matter in the strongly-interacting regime.

4 pages, appendix (5 pages)

References in corpus (10)

• The density-matrix renormalization group in the age of matrix product states
• Time-evolving a matrix product state with long-ranged interactions
• Spontaneous Magnon Decays
• Spectral Function for the S=1 Heisenberg Antiferromagetic Chain
• Excitation spectra of the spin-1/2 triangular-lattice Heisenberg antiferromagnet
• Quantum Dynamics of the Square-Lattice Heisenberg Model
• Quantum magnetic properties of the spin-1/2 triangular-lattice antiferromagnet Ba${}_2$La${}_2$CoTe${}_2$O${}_{12}$
• "Quasi-particle breakdown" in the quasi-one-dimensional Ising ferromagnet CoNb${}_2$O${}_6$
• Decay of quasiparticles in quantum spin liquids
• Landau-Zener-Stueckelberg physics with a singular continuum of states

Cited by in corpus (56)

• Quantum Many-Body Scars: A Quasiparticle Perspective
• Interaction-stabilized topological magnon insulator in ferromagnets
• Kosterlitz-Thouless Melting of Magnetic Order in the Triangular Quantum Ising Material TmMgGaO${}_4$
• Spin liquids in geometrically perfect triangular antiferromagnets
• Excitations with projected entangled pair states using the corner transfer matrix method
• Avoided quasiparticle decay and enhanced excitation continuum in the spin-1/2 near-Heisenberg triangular antiferromagnet Ba3CoSb2O9
• Spin Excitation Spectra of Anisotropic Spin-$1/2$ Triangular Lattice Heisenberg Antiferromagnets
• Glide symmetry breaking and Ising criticality in the quasi-1D magnet CoNb${}_2$O${}_6$
• Bond-dependent anisotropy and magnon decay in cobalt-based Kitaev triangular antiferromagnet
• Magnon damping in the zigzag phase of the Kitaev-Heisenberg-$\Gamma$ model on a honeycomb lattice
• Spectral function of the $J_1-J_2$ Heisenberg model on the triangular lattice
• Dynamical Signatures of Symmetry Broken and Liquid Phases in an $S=1/2$ Heisenberg Antiferromagnet on the Triangular Lattice
• Magnon interactions in the frustrated pyrochlore ferromagnet Yb${}_2$Ti${}_2$O${}_7$
• Topological polarons, quasiparticle invariants and their detection in 1D symmetry-protected phases
• Quantum spin state transitions in spin-1 equilateral triangular lattice antiferromagnet Na${}_2$BaNi(PO${}_4$)${}_2$
• Double Magnon-Roton Excitations in the Triangular-Lattice Spin Supersolid
• Quantum Spin Dynamics Due to Strong Kitaev Interactions in the Triangular-Lattice Antiferromagnet CsCeSe${}_2$
• Theory of the anomalous spin dynamics of spin-$\frac{1}{2}$ triangular lattice Heisenberg antiferromagnet and its application to Ba${}_3$CoSb${}_2$O${}_9$
• Instabilities of heavy magnons in an anisotropic magnet
• Highly resolved spectral functions of two-dimensional systems with neural quantum states
• Rotational Resonances and Regge Trajectories in Lightly Doped Antiferromagnets
• Two-dimensional coherent spectrum of interacting spinons from matrix-product states
• Magnon spectrum of altermagnets beyond linear spin wave theory: Magnon-magnon interactions via time-dependent matrix product states vs. atomistic spin dynamics
• Topological Hybrids of Magnons and Magnon Bound Pairs
• Shedding Light on Microscopic Details: 2D Spectroscopy of 1D Quantum Ising Magnets
• Structures of magnetic excitations in the spin-1/2 kagome-lattice antiferromagnets Cs${}_2$Cu${}_3$SnF${}_{12}$ and Rb${}_2$Cu${}_3$SnF${}_{12}$
• Magnon interactions in the quantum paramagnetic phase of CoNb${}_2$O${}_6$
• Anomalous continuum scattering and higher-order van Hove singularity in the strongly anisotropic S = 1/2 triangular lattice antiferromagnet
• Novel elementary excitations in spin-1/2 antiferromagnets on the triangular lattice
• Magnons and Spinons in ${\mathrm{Ba}}_2{\mathrm{CoTeO}}_6$: A Composite System of Isolated Spin-$1/2$ Triangular Heisenberg-like and Frustrated Honeycomb Ising-like Antiferromagnets
• Momentum-dependent magnon lifetime in the metallic non-collinear triangular antiferromagnet CrB2
• Spectral functions with infinite projected entangled-pair states
• Momentum-resolved time evolution with matrix product states
• Classical dynamics of the antiferromagnetic Heisenberg $S=1/2$ spin ladder
• Why the Schwinger Boson mean field theory fails to describe the spin dynamics of the triangular lattice antiferromagnetic Heisenberg model?
• Dynamical response theory of interacting Majorana fermions and its application to generic Kitaev quantum spin liquids in a field
• From continuum excitations to sharp magnons via transverse magnetic field in the spin-1/2 Ising-like triangular lattice antiferromagnet Na2BaCo(PO4)2
• Topological phase transitions and thermal Hall effect in a noncollinear spin texture
• Particle zoo in a doped spin chain: Correlated states of mesons and magnons
• Interaction-induced nonlinear magnon transport in noncentrosymmetric magnets
• Dynamic structure factor of the antiferromagnetic Kitaev model in large magnetic fields
• Non-magnetic ion site disorder effects on the quantum magnetism of a spin-1/2 equilateral triangular lattice antiferromagnet
• Rare collapse of fermionic quasiparticles upon coupling to local bosons
• Interacting triplons in frustrated spin ladders: Binding and decay in BiCu${}_2$PO${}_6$
• Confinement and oscillating deconfinement crossover of two-magnon excitations in quantum spin chains quantified by spin entanglement entropy
• Temperature dependence of the $(\pi ,0)$ anomaly in the excitation spectrum of the 2D quantum Heisenberg antiferromagnet
• Density Functional Equation of State and Its Application to the Phenomenology of Heavy-Ion Collisions
• Spectroscopy and complex-time correlations using minimally entangled typical thermal states
• The fate of the spin polaron in the 1D antiferromagnets
• Hybridization of the amplitude mode in a confined fermionic superfluid
• Interaction-mitigated Landau damping
• Field-Induced Magnon Decay, Magnon Shadows, and Roton-like Excitations in the Honeycomb Antiferromagnet YbBr${}_3$
• Coupling of plasmons to the two-magnon continuum in antiferromagnets
• Dissipationless dynamics of spin supersolid states in a spin-1/2 triangular antiferromagnet with impurities
• One-dimensional physics of the frustrated quantum magnet PHCC
• Fate of Bosonic Topological Edge Modes in the Presence of Many-Body Interactions