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update the results on M matrix in the two-hole example to match with the meshes used.
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docs/src/examples/circular_hole.md

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@@ -287,35 +287,44 @@ matrix from the stored magnetic energy:
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M_{ij} = \frac{\mathbf{A}_j^T K \mathbf{A}_i}{\Phi_i \Phi_j},
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```
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where ``K`` is the curl-curl stiffness matrix. The off-diagonal entries ``M_{ij}``
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(``i \neq j``) represent the mutual inductance between loops, quantifying their magnetic
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coupling. For the two-hole configuration on a shared plate, the computed inductance matrix
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is:
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where ``K`` is the curl-curl stiffness matrix. The diagonal entries ``M_{ii}`` give the
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self-inductance of each flux loop, which is the energy cost of trapping one flux quantum in hole
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``i``. The off-diagonal entries ``M_{ij}`` (``i \neq j``) give the mutual
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inductance, which captures how the magnetic field generated by a flux quantum in one hole
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influences the other.
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For the two-hole configuration on a shared plate, the computed inductance matrix is:
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```math
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M = \begin{pmatrix}
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2.8076 & 0.4654 \\
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0.4654 & 2.8080
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1.909 & -1.405 \times 10^{-5} \\
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-1.405 \times 10^{-5} & 1.909
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\end{pmatrix} \text{pH}
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```
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The nearly equal self-inductances reflect the geometric symmetry, while the mutual
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inductance (about 17% of the self-inductance) indicates moderate magnetic coupling at this
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hole separation.
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The equal self-inductances reflect the geometric symmetry of the two holes. The mutual
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inductance is five orders of magnitude
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smaller than the self-inductance, indicating that despite being on the same plate, the two
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holes are magnetically nearly independent at this separation: a flux quantum trapped in one
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hole has negligible influence on the shielding currents around the other.
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### Two holes on separate planes
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For the configuration with holes on spatially separated plates, the inductance matrix is:
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When the two holes are placed on spatially separated plates, the inductance matrix is:
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```math
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M = \begin{pmatrix}
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2.9989 & -0.0510 \\
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-0.0510 & 2.9988
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1.839 & -1.134 \times 10^{-5}\\
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-1.134 \times 10^{-5} & 1.829
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\end{pmatrix} \text{pH}
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```
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The mutual inductance is an order of magnitude smaller than in the shared-plate case, despite
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the same center-to-center separation between holes. This reduction arises because the
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surface currents generated by each trapped flux are confined to their respective plates and
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cannot overlap with the other hole's current distribution, greatly suppressing the inductive
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coupling.
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The self-inductances are slightly smaller than in the shared-plate case because the
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surrounding metal no longer extends as far, reducing the flux return path. The mutual
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inductance is comparable in magnitude to the shared-plate result, which may be
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counterintuitive. The key reason is that mutual inductance in this geometry is dominated
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by the far-field magnetic interaction between the two holes, which depends mainly on their
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center-to-center separation -- not on whether they share a plate. The shielding currents
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flowing around each hole are confined to their own plate and cannot cross over to the other,
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but the magnetic field itself still permeates the surrounding space and couples the two
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loops at long range.

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