Past exam of the mathematics course of the University of Cambridge 2016 iii Paper 304 3 iii Solution Created 2026-10-03 Updated 2026-10-06
Rescale with . After Berezin integration, the unnormalized holomorphic function insertion isIts derivative is an ordinary total derivative:The last equality again follows from polynomial growth and exponential decay. Thus the insertion is independent of , and supersymmetric localization allows evaluation as at the zeros of , as in localization of a zero-dimensional polynomial model.
For a simple zero , . The local Gaussian integral cancels the factor and contributes . For a zero with multiplicity of a root , write . Its leading radial integral isThe insertion tends to there; contributions away from the zeros vanish. Therefore the full answer, including degenerate critical points, isThis is an unnormalized expectation. For simple zeros all ; division by would give the normalized average, but is not part of the requested insertion. Taking recovers the partition function, and taking recovers its vanishing supersymmetric Ward identity.
Past exam of the mathematics course of the University of Cambridge 2016 iii Paper 304 3 ii Solution Created 2026-10-03 Updated 2026-10-06
The odd symmetries of a zero-dimensional polynomial model preserve both the action and the flat integration measure: their coefficients have zero superdivergence. The confining polynomial weight removes boundary terms at infinity. Thus the integral of an odd-symmetry derivative is zero, a supersymmetric Ward identity for this finite-dimensional integral in this zero-dimensional supersymmetric field theory.
Since is a holomorphic function, the barred symmetry obeys . Applying the supersymmetric Ward identity gives the requested unnormalized insertion:One can also verify the result after Berezin integration, without invoking the symmetry terminology:The final integration by parts uses and rapid decay. The derivative on in the insertion is essential.
Supersymmetric localization 2026-10-06
A symmetry-preserving deformation can leave protected observables unchanged while concentrating their integral on a smaller critical locus. Supersymmetric Ward identities justify the deformation; convergence and boundary terms must be controlled.
Zero-dimensional supersymmetric field theory 2026-10-06
A zero-dimensional model is a finite-dimensional integral with bosonic and Grassmann variables, rather than a field depending on spacetime. Odd graded derivations preserve its action and integration measure. Such models expose supersymmetric Ward identities and supersymmetric localization without spacetime dynamics.