Problems / differential-equations
differential-equations / Dispersive PDE; nonlinear Schrodinger equation; random data; blowup
Almost-sure global well-posedness for high-regularity random data in energy-supercritical defocusing NLS (Deng-Nahmod-Yue Open Problem 3), refuted on the twelve-torus
Claims: there are an odd p (which can be taken arbitrarily large), an integer k>8 and a nonempty open set U⊂Hk(T12) such that every solution of the defocusing NLS with data in U blows up in finite time T with (T−t)1/(p−1)∣u(t,x∗)∣→c0>0, a type-I self-similar singularity with logarithmic phase. Since Gaussian measures charge open sets, for every α>k+6 the Gaussian Fourier datum blows up with positive probability, so almost-sure global existence for high-regularity random data fails for this (d,p). It does NOT give probability-one blowup, a bound uniform in α, an explicit p, or anything for low dimensions such as d≤11; the question for other pairs (d,p) stays open.