Large deviation principles for the Gross Pitaevskii Gibbs measure at low temperature
Liam Packer, Kihoon Seong, Philippe Sosoe
TL;DR
This work proves a large deviation principle for the focusing Gross–Pitaevskii Gibbs measure in the low-temperature limit under a mixed canonical in energy and microcanonical in mass conditioning. The analysis proceeds via the grand canonical ensemble, employing the Laplace principle and Gamma-convergence to obtain a rate function $J^D(\phi)=H(\phi)-\inf_{M(\phi)=D}H(\phi)$, while showing that diverging Wick renormalization constants cancel in the rate function. Consequently, the conditional Gibbs measure concentrates on the soliton manifold $\mathcal{M}^D$, i.e., the minimizers of $H$ under $M(\phi)=D$, and the long-time GP dynamics are captured by fluctuations around these ground states. The results extend prior mixed-ensemble LDPs to unbounded quartic interactions and singular conditioning, leveraging confinement by the harmonic potential to obtain a nontrivial infinite-volume measure and making the macroscopic behavior robust to renormalization effects.
Abstract
We prove the large deviation principle for the conditional Gibbs measure associated with the focusing Gross Pitaevskii equation in the low temperature regime. This conditional measure is of mixed type, being canonical in energy and microcanonical in particle number. In particular, our result extends the large deviation principle for the mixed ensemble studied by Ellis, Jordan, Otto, and Turkington to a more singular setting, where the interaction potential is unbounded and the conditional event involves diverging renormalization constants. As a consequence of the large deviation principle, the Gibbs measure concentrates along the soliton manifold in the low temperature limit.
