周四讨论班题目：最近关于磁单极的实验报道

关于最近的磁单极实验，这里有一个简要的报道：http://www.sciencedaily.com/releases/2009/09/090903163725.htm

这里是那篇文章：
D.J.P. Morris, D.A. Tennant, S.A. Grigera, B. Klemke, C. Castelnovo, R. Moessner, C. Czter-nasty, M. Meissner, K.C. Rule, J.-U. Hoffmann, K. Kiefer, S. Gerischer, D. Slobinsky, and R.S. Perry. Dirac Strings and Magnetic Monopoles in Spin Ice Dy₂Ti₂O₇. Science, 2009

此外还有以前的一些相关内容：

C. Castelnovo; R. Moessner1, S. L. Sondhi，Magnetic monopoles in spin ice．Nature，451：42-45（2008）．

另一个相关内容：

'Magnetricity' observed for first time

The transport of electrically charged quasiparticles (based on electrons or ions) plays a pivotal role in modern technology as well as in determining the essential functions of biological organisms. In contrast, the transport of magnetic charges has barely been explored experimentally, mainly because magnetic charges, in contrast to electric ones, are generally considered at best to be convenient macroscopic parameters^{1, 2}, rather than well-defined quasiparticles. However, it was recently proposed that magnetic charges can exist in certain materials in the form of emergent excitations that manifest like point charges, or magnetic monopoles³. Here we address the question of whether such magnetic charges and their associated currents—'magnetricity'—can be measured directly in experiment, without recourse to any material-specific theory. By mapping the problem onto Onsager's theory of electrolytes⁴, we show that this is indeed possible, and devise an appropriate method for the measurement of magnetic charges and their dynamics. Using muon spin rotation as a suitable local probe, we apply the method to a real material, the 'spin ice' Dy₂Ti₂O₇ (refs 5–8). Our experimental measurements prove that magnetic charges exist in this material, interact via a Coulomb potential, and have measurable currents. We further characterize deviations from Ohm's law, and determine the elementary unit of magnetic charge to be 5 _B Å^-1, which is equal to that recently predicted using the microscopic theory of spin ice³. Our measurement of magnetic charge and magnetic current establishes an instance of a perfect symmetry between electricity and magnetism.

S. T. Bramwell, S. R. Giblin, S. Calder, R. Aldus, D. Prabhakaran & T. Fennell, Measurement of the charge and current of magnetic monopoles in spin ice， Nature 461, 956-959 (15 October 2009)

这里的文献是我随便搜索了一下找到的，做这个讲座的同学还需要先仔细查一下相关文献。

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