发信人: cmnll (cmn@phys), 信区: D_Physics
标 题: 磁单极子找到了
发信站: 南京大学小百合站 (Thu Jan 30 21:13:05 2014)
http://www.nature.com/nature/journal/v505/n7485/pdf/nature12954.pdf
摘要如下：
Magnetic monopoles—particles that behave as isolated north or south magnetic
poles—have been the subject of speculation since the first detailed
observations of magnetism several hundred years ago1. Numerous theoretical
investigations and hitherto unsuccessful experimental searches2 have followed
Dirac’s 1931 development of a theory of monopoles consistent with both
quantum mechanics and the gauge invariance of the electromagnetic field3. The
existence of even a single Dirac magnetic monopole would have far-reaching
physical consequences, most famously explaining the quantization of electric
charge3, 4. Although analogues of magnetic monopoles have been found in exotic
spin ices5, 6 and other systems7, 8, 9, there has been no direct experimental
observation of Dirac monopoles within a medium described by a quantum field,
such as superfluid helium-3 (refs 10, 11, 12, 13). Here we demonstrate the
controlled creation14 of Dirac monopoles in the synthetic magnetic field
produced by a spinor Bose–Einstein condensate. Monopoles are identified, in
both experiments and matching numerical simulations, at the termini of vortex
lines within the condensate. By directly imaging such a vortex line, the
presence of a monopole may be discerned from the experimental data alone.
These real-space images provide conclusive and long-awaited experimental
evidence of the existence of Dirac monopoles. Our result provides an
unprecedented opportunity to observe and manipulate these quantum mechanical
entities in a controlled environment.
--
※ 来源:．南京大学小百合站 http://bbs.nju.edu.cn [FROM: 123.97.0.24]
标 题: 磁单极子找到了
发信站: 南京大学小百合站 (Thu Jan 30 21:13:05 2014)
http://www.nature.com/nature/journal/v505/n7485/pdf/nature12954.pdf
摘要如下：
Magnetic monopoles—particles that behave as isolated north or south magnetic
poles—have been the subject of speculation since the first detailed
observations of magnetism several hundred years ago1. Numerous theoretical
investigations and hitherto unsuccessful experimental searches2 have followed
Dirac’s 1931 development of a theory of monopoles consistent with both
quantum mechanics and the gauge invariance of the electromagnetic field3. The
existence of even a single Dirac magnetic monopole would have far-reaching
physical consequences, most famously explaining the quantization of electric
charge3, 4. Although analogues of magnetic monopoles have been found in exotic
spin ices5, 6 and other systems7, 8, 9, there has been no direct experimental
observation of Dirac monopoles within a medium described by a quantum field,
such as superfluid helium-3 (refs 10, 11, 12, 13). Here we demonstrate the
controlled creation14 of Dirac monopoles in the synthetic magnetic field
produced by a spinor Bose–Einstein condensate. Monopoles are identified, in
both experiments and matching numerical simulations, at the termini of vortex
lines within the condensate. By directly imaging such a vortex line, the
presence of a monopole may be discerned from the experimental data alone.
These real-space images provide conclusive and long-awaited experimental
evidence of the existence of Dirac monopoles. Our result provides an
unprecedented opportunity to observe and manipulate these quantum mechanical
entities in a controlled environment.
--
※ 来源:．南京大学小百合站 http://bbs.nju.edu.cn [FROM: 123.97.0.24]
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