Effects of coupling between chains on the magnetic excitation spectrum of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">KCuF</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Tennant, A.; Nagler, S. E.; Welz, D.; Shirane, G.; Yamada, K.

doi:10.1103/physrevb.52.13381

Cited by 70 publications

(93 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If we move away from simply including single spin flip corrections to ͉⌿͘ and also take account of RVB-like terms (23), as illustrated in Fig. 1e, the structure of the continuum can be substantially altered from that given by two-magnon calculations, as borne out by the different predictions given by competing theoretical scenarios (26,29). The unambiguous observation of multimagnon continuum scattering is highly nontrivial, because of the difficulty of isolating a weak, diffuse signal from the one-magnon signal in the presence of scattering from phonons, nonuniform background, etc.…”

Section: Resultsmentioning

confidence: 99%

Quantum dynamics and entanglement of spins on a square lattice

Christensen

Rønnow

McMorrow

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

133

151

View full text Add to dashboard Cite

Bulk magnetism in solids is fundamentally quantum mechanical in nature. Yet in many situations, including our everyday encounters with magnetic materials, quantum effects are masked, and it often suffices to think of magnetism in terms of the interaction between classical dipole moments. Whereas this intuition generally holds for ferromagnets, even as the size of the magnetic moment is reduced to that of a single electron spin (the quantum limit), it breaks down spectacularly for antiferromagnets, particularly in low dimensions. Considerable theoretical and experimental progress has been made in understanding quantum effects in one-dimensional quantum antiferromagnets, but a complete experimental description of even simple two-dimensional antiferromagnets is lacking. Here we describe a comprehensive set of neutron scattering measurements that reveal a non-spin-wave continuum and strong quantum effects, suggesting entanglement of spins at short distances in the simplest of all two-dimensional quantum antiferromagnets, the square lattice Heisenberg system. antiferromagnetism ͉ entanglement ͉ multimagnons ͉ spin waves O ne of the most fundamental exercises in quantum mechanics is to consider a pair of S ϭ 1/2 spins with an interaction J between them that favors either parallel (ferromagnetic) or antiparallel (antiferromagnetic) alignment. The former results in a spin S tot ϭ 1 ground state, which is a degenerate triplet. Two of the states in this triplet are the possible classical ground states ͉11͘ and ͉22͘, whereas the third is the coherent symmetric superposition ͉12͘ϩ͉21͘, which has no classical analogue. Even more interesting is antiferromagnetic J, for which the ground state is the entirely nonclassical S tot ϭ 0 singlet ͉0͘ ϭ ͉12͘ Ϫ ͉21͘ consisting of the antisymmetric coherent superposition of the two classical ground states of the pair. The state ͉0͘ is an example of maximal entanglement, i.e., a wavefunction for two coupled systems that cannot be written as the product of eigenfunctions for the two separate systems, which in this case are of course the two spins considered individually.

show abstract

Section: Resultsmentioning

confidence: 99%

Quantum dynamics and entanglement of spins on a square lattice

Christensen

Rønnow

McMorrow

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

133

151

View full text Add to dashboard Cite

show abstract

“…However, below this energy well-defined spin-wave modes were found but with additional scattering lying between them for energies ω 12 meV. Conventional 3D spinwave theory (SWT) with the inclusion of two-magnon terms could qualitatively explain the observations at low-energies [10] but not the continuum at higher energies. al.…”

mentioning

confidence: 94%

“…predict continuum scattering starting at 22 meV and extending upwards [6]. The scan coverage and resolution in previous measurements [10] was insufficient to differentiate between the RPA and SWT so new experiments probing the low-energy sector were necessary to determine the existence of the longitudinal mode.…”

mentioning

confidence: 99%

Novel Longitudinal Mode in the Coupled Quantum Chain CompoundKCuF3

2000

View full text Add to dashboard Cite

Inelastic neutron scattering measurements are reported that show a new longitudinal mode in the antiferromagnetically ordered phase of the spin-1/2 quasi-one-dimensional antiferromagnet KCuF 3 . This mode signals the cross-over from one-dimensional to three-dimensional behavior and indicates a reduction in the ordered spin moment of a spin-1/2 antiferromagnet. The measurements are compared with recent quantum field theory results and are found to be in excellent agreement. A feature of the data not predicted by theory is a damping of the mode by decay processes to the transverse spin-wave branches.

show abstract

“…For a comprehensive historic review, the importance of the DCF, an account of the existing results, and a list of references on this subject we recommend Refs. [4,5,6,7,8,9]. In particular, in Ref.…”

Section: Introductionmentioning

confidence: 99%