Experimental observation of Bethe strings

  title={Experimental observation of Bethe strings},
  author={Zhe Wang and Jianda Wu and Wang Yang and Anup Kumar Bera and Dmytro Kamenskyi and Atm Nazmul Islam and Shenglong Xu and Joseph M. Law and Bella Lake and Congjun Wu and Alois Loidl},
Almost a century ago, string states—complex bound states of magnetic excitations—were predicted to exist in one-dimensional quantum magnets. However, despite many theoretical studies, the experimental realization and identification of string states in a condensed-matter system have yet to be achieved. Here we use high-resolution terahertz spectroscopy to resolve string states in the antiferromagnetic Heisenberg–Ising chain SrCo2V2O8 in strong longitudinal magnetic fields. In the field-induced… 
Dispersions of many-body Bethe strings
Complex bound states of magnetic excitations, known as Bethe strings, were predicted almost a century ago to exist in one-dimensional quantum magnets 1 . The dispersions of the string states have so
One-dimensional quantum spin dynamics of Bethe string states
Quantum dynamics of strongly correlated systems is a challenging problem. Although the low energy fractional excitations of one dimensional integrable models are often well-understood, exploring
Quantum Critical Dynamics of a Heisenberg-Ising Chain in a Longitudinal Field: Many-Body Strings versus Fractional Excitations.
A high-resolution terahertz spectroscopic study of quantum spin dynamics in the antiferromagnetic Heisenberg-Ising spin-chain compound BaCo-V-O-8 as a function of temperature and longitudinal magnetic field finds the high-energy string excitations are found to have a dominant contribution to the spin dynamics as compared with the fractional excitations.
Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3
This work investigates the Heisenberg spin-chain compound YbAlO3 and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems.
Dynamical Signatures of Quasiparticle Interactions in Quantum Spin Chains.
In the high magnetization regime, as the Zeeman field approaches the saturation value, the appearance of two-magnon bound states in the transverse susceptibility is uncovered, which generalizes the one arising from string states inThe Bethe ansatz solution of the integrable case.
Real-time dynamics of string breaking in quantum spin chains
It is shown that string breaking can be observed in quantum Ising chains where domain walls get confined either by a symmetry-breaking field or by long-range interactions, and an effective description of this motion is developed, which is strongly constrained.
Experimental observation of quantum many-body excitations of E8 symmetry in the Ising chain ferromagnet CoNb2O6
Close to the quantum critical point of the transverse-field Ising spin-chain model, an exotic dynamic spectrum was predicted to emerge upon a perturbative longitudinal field. The dynamic spectrum
Fractional and composite excitations of antiferromagnetic quantum spin trimer chains
Using quantum Monte Carlo, exact diagonalization, and perturbation theory, we study the spectrum of the S  = 1/2 antiferromagnetic Heisenberg trimer chain by varying the ratio g  =  J 2 / J 1 of the
Confinement in the spectrum of a Heisenberg–Ising spin ladder
The Heisenberg–Ising spin ladder is one of the few short-range models showing confinement of elementary excitations without the need of an external field, neither transverse nor longitudinal. This


Microscopic observation of magnon bound states and their dynamics
In situ correlation measurements are used to observe two-magnon bound states directly in a one-dimensional Heisenberg spin chain comprising ultracold bosonic atoms in an optical lattice and determine the decay time of bound magnons.
Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain
One of the simplest quantum many-body systems is the spin-1/2 Heisenberg antiferromagnetic chain, a linear array of interacting magnetic moments. Its exact ground state is a macroscopic singlet
Observation of complex bound states in the spin-1/2 Heisenberg XXZ chain using local quantum quenches.
This work considers the nonequilibrium evolution in the spin-1/2 XXZ Heisenberg chain for fixed magnetization after a local quantum quench and finds that the observables exhibit strong signatures of linearly propagating spinon and bound state excitations.
Quantum criticality of spinons
The free fermion nature of interacting spins in one dimensional (1D) spin chains still lacks a rigorous study. In this letter we show that the length-$1$ spin strings significantly dominate critical
Quantum spin dynamics of the antiferromagnetic linear chain in zero and nonzero magnetic field
Spin-dynamical calculations on one-dimensional systems have relied heavily on classical ($s=\ensuremath{\infty}$) theories, despite abundant evidence that quantum effects can be extremely important
Spinon confinement in a quasi-one-dimensional anisotropic Heisenberg magnet
Confinement is a process by which particles with fractional quantum numbers bind together to form quasiparticles with integer quantum numbers. The constituent particles are confined by an attractive
Dynamically dominant excitations of string solutions in the spin-1/2 antiferromagnetic Heisenberg chain in a magnetic field.
  • M. Kohno
  • Physics
    Physical review letters
  • 2009
Using Bethe-ansatz solutions, this Letter uncovers a well-defined continuum in dynamical structure factor S+-(k,omega) of the spin-1/2 antiferromagnetic Heisenberg chain in magnetic fields. It comes
From confined spinons to emergent fermions: Observation of elementary magnetic excitations in a transverse-field Ising chain
We report on spectroscopy study of elementary magnetic excitations in an Ising-like antiferromagnetic chain compound ${\mathrm{SrCo}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ as a function of temperature
Extended quantum critical phase in a magnetized spin-1/2 antiferromagnetic chain.
Measurements are reported of the magnetic field dependence of excitations in the quantum critical state of the spin S=1/2 linear chain Heisenberg antiferromagnet copper pyrazine dinitrate (CuPzN), and the intensities are consistent with exact diagonalization and Bethe ansatz calculations.
Spinon Confinement in the One-Dimensional Ising-Like Antiferromagnet SrCo2V2O8
For quasi-one dimensional quantum spin systems theory predicts the occurrence of a confinement of spinon excitation due to interchain couplings. Here we investigate the system SrCo2V2O8, a