最近科学界最热闹的大概是科学家声称探测到磁单极子，这里没有提只好偶这个业余爱好者随便说说了。

上周的《科学》杂志发表了两篇论文：

Magnetic Coulomb Phase in the Spin Ice Ho₂Ti₂O₇

T. Fennell ^1*, P. P. Deen ¹, A. R. Wildes ¹, K. Schmalzl ², D. Prabhakaran ³, A. T. Boothroyd ³, R. J. Aldus ⁴, D. F. McMorrow ⁴, S. T. Bramwell ⁴

Spin ice materials are magnetic substances in which the spin directions map onto hydrogen positions in water ice. Their low-temperature magnetic state has been predicted to be a phase that obeys a Gauss’ Law and supports magnetic monopole excitations: in short, a "Coulomb phase." Here, we use polarized neutron scattering to show that the spin ice material Ho₂Ti₂O₇ exhibits an almost perfect Coulomb phase. Our result proves the existence of such phases in magnetic materials and strongly supports the magnetic monopole theory of spin ice.

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