论文标题
外部磁场引起的QED中的手性对称性破裂
Chiral Symmetry Breaking in QED induced by an External Magnetic Field
论文作者
论文摘要
我们使用RHMC算法在恒定的外部磁场中模拟晶格QED。我们寻求通过截断的施温格·戴森方法预测的手性对称性破坏的证据。由于在物理细胞结构常数处的动态电子质量和手性冷凝物的预测值太小而无法测量，因此我们以较大的值$α= 1/5 $进行模拟。这需要使用低至$ m = 0.001 $的电子质量才能推断至$ m = 0 $。在大磁场上，电子占据最低的Landau水平，该水平在平面与磁场的正交中具有较小的轮廓，因此我们能够在这两个方向上使用较小程度的晶格。如果手性对称性在$ M = 0 $时不间断，手性冷凝物由大动量主导，应对磁场方向和时间方向的晶格范围不敏感。当手性对称性以$ M = 0 $打破时，手性冷凝物应以$ M \ rightarrow 0 $敏感。我们通过在这两个方向上增加晶格范围来搜索这种行为。初步模拟表明，手性冷凝物在这两个方向上对晶格范围的最大依赖性对于最小的质量，这些增加的冷凝水似乎已接近非零极限为$ m \ rightarrow 0 $。
We simulate Lattice QED in a constant external magnetic field using the RHMC algorithm. We seek evidence for chiral symmetry breaking predicted by truncated Schwinger-Dyson methods. Since the predicted values of the dynamical electron mass and chiral condensate at the physical fine structure constant are too small to be measured, we simulate at a larger value $α=1/5$. This requires using electron masses as low as $m=0.001$ to extrapolate to $m=0$. At a large magnetic field, the electrons occupy the lowest Landau level which has a small profile in the plane orthogonal to the magnetic field, so that we are able to use a lattice with small extent in these 2 directions. If chiral symmetry is unbroken at $m=0$ the chiral condensate is dominated by large momenta and should be insensitive to the lattice extent in the direction of the magnetic field and the time direction. When chiral symmetry is broken at $m=0$, the chiral condensate should be sensitive to the lattice size in these directions as $m \rightarrow 0$. We search for this behaviour by increasing the lattice extent in these 2 directions. Preliminary simulations show strong dependence of the chiral condensate on the lattice extent in these 2 directions for the smallest masses, and these increased condensates appear to be approaching a non-zero limit as $m \rightarrow 0$.
