Quantum dynamics and entanglement of spins on a square lattice

被引:102
作者
Christensen, N. B. [1 ]
Ronnow, H. M.
McMorrow, D. F.
Harrison, A.
Perring, T. G.
Enderle, M.
Coldea, R.
Regnault, L. P.
Aeppli, G.
机构
[1] Tech Univ Denmark, Riso Natl Lab, Dept Mat Res, DK-4000 Roskilde, Denmark
[2] Swiss Fed Inst Technol, Neutron Scattering Lab, CH-5232 Villigen, Switzerland
[3] Paul Scherrer Inst, CH-5232 Villigen, Switzerland
[4] Ecole Polytech Fed Lausanne, Lab Quantum Magnetism, CH-1015 Lausanne, Switzerland
[5] UCL, Dept Phys & Astron, London WC1H 0AH, England
[6] Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England
[7] Univ Edinburgh, Dept Chem, Edinburgh EH9 3JJ, Midlothian, Scotland
[8] Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France
[9] Clarendon Lab, Oxford Phys, Oxford OX1 3PU, England
[10] Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England
[11] CEA Grenoble, Dept Rech Fondamentale Mat Condensee, F-38054 Grenoble 9, France
[12] UCL, London Ctr Nanotechnol, London WC1H 0AH, England
基金
英国工程与自然科学研究理事会;
关键词
antiferromagnetism; entanglement; multimagnons; spin waves;
D O I
10.1073/pnas.0703293104
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
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.
引用
收藏
页码:15264 / 15269
页数:6
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