@@ -287,35 +287,44 @@ matrix from the stored magnetic energy:
287287M_{ij} = \frac{\mathbf{A}_j^T K \mathbf{A}_i}{\Phi_i \Phi_j},
288288```
289289
290- where `` K `` is the curl-curl stiffness matrix. The off-diagonal entries `` M_{ij} ``
291- (`` i \neq j `` ) represent the mutual inductance between loops, quantifying their magnetic
292- coupling. For the two-hole configuration on a shared plate, the computed inductance matrix
293- is:
290+ where `` K `` is the curl-curl stiffness matrix. The diagonal entries `` M_{ii} `` give the
291+ self-inductance of each flux loop, which is the energy cost of trapping one flux quantum in hole
292+ `` i `` . The off-diagonal entries `` M_{ij} `` (`` i \neq j `` ) give the mutual
293+ inductance, which captures how the magnetic field generated by a flux quantum in one hole
294+ influences the other.
295+
296+ For the two-hole configuration on a shared plate, the computed inductance matrix is:
294297
295298``` math
296299M = \begin{pmatrix}
297- 2.8076 & 0.4654 \\
298- 0.4654 & 2.8080
300+ 1.909 & -1.405 \times 10^{-5} \\
301+ -1.405 \times 10^{-5} & 1.909
299302\end{pmatrix} \text{pH}
300303```
301304
302- The nearly equal self-inductances reflect the geometric symmetry, while the mutual
303- inductance (about 17% of the self-inductance) indicates moderate magnetic coupling at this
304- hole separation.
305+ The equal self-inductances reflect the geometric symmetry of the two holes. The mutual
306+ inductance is five orders of magnitude
307+ smaller than the self-inductance, indicating that despite being on the same plate, the two
308+ holes are magnetically nearly independent at this separation: a flux quantum trapped in one
309+ hole has negligible influence on the shielding currents around the other.
305310
306311### Two holes on separate planes
307312
308- For the configuration with holes on spatially separated plates, the inductance matrix is:
313+ When the two holes are placed on spatially separated plates, the inductance matrix is:
309314
310315``` math
311316M = \begin{pmatrix}
312- 2.9989 & -0.0510 \\
313- -0.0510 & 2.9988
317+ 1.839 & -1.134 \times 10^{-5} \\
318+ -1.134 \times 10^{-5} & 1.829
314319\end{pmatrix} \text{pH}
315320```
316321
317- The mutual inductance is an order of magnitude smaller than in the shared-plate case, despite
318- the same center-to-center separation between holes. This reduction arises because the
319- surface currents generated by each trapped flux are confined to their respective plates and
320- cannot overlap with the other hole's current distribution, greatly suppressing the inductive
321- coupling.
322+ The self-inductances are slightly smaller than in the shared-plate case because the
323+ surrounding metal no longer extends as far, reducing the flux return path. The mutual
324+ inductance is comparable in magnitude to the shared-plate result, which may be
325+ counterintuitive. The key reason is that mutual inductance in this geometry is dominated
326+ by the far-field magnetic interaction between the two holes, which depends mainly on their
327+ center-to-center separation -- not on whether they share a plate. The shielding currents
328+ flowing around each hole are confined to their own plate and cannot cross over to the other,
329+ but the magnetic field itself still permeates the surrounding space and couples the two
330+ loops at long range.
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