Events List

DateEvent TypeSpeaker
05/01/2025Special SeminarLyman Page [ + ]
05/01/2025Physics Dept ColloquiumLyman Page [ + ]
05/02/2025Hep-Th Discussion SessionCalkins [ + ]
05/05/2025CCPP Brown BagWenzer Qin [ + ]
05/06/2025Astro SeminarTetyana Pitik [ + ]
05/07/2025HEP Journal Club [ + ]
05/07/2025HEP SeminarHowie Haber [ + ]
05/09/2025Special SeminarVladimir Rosenhaus [ -- ]

Title: Renormalization Group in wave turbulence
Abstract: *HOSTED BY COURANT - OF POTENTIAL INTEREST TO CCPP* Renormalization Group (RG) is a powerful concept -- one calculates partition functions by successively integrating out short distance degrees of freedom, until one has an effective Hamiltonian describing only large scale modes. The most famous application is Wilson's use of RG to calculate the critical scaling exponents at the water-vapor phase transition. We apply RG concepts to a vastly different class of states, which are far from equilibrium. It is known that a large class of weakly interacting nonlinear systems have states that are spatially homogeneous, time-independent, and scale invariant. Such states, in which mode k has occupation number $n_k = k^{-gamma}$, go under the name of Kolmogorov-Zakharov states in wave turbulence. Canonical examples are waves on the surface of the ocean, or waves in the nonlinear Schrodinger equation. We compute one loop beta functions in such states, which encode how the effective coupling changes with scale. The beta functions tells us if the spectrum of occupation numbers is steeper or less steep than Kolmogorov-Zakharov scaling. Depending on the sign of the beta function, nonlinear effects may either cause a minor shift of the state in the IR, or completely change the nature of the state. Focusing on nearly marginal interactions (ones in which the strength of the nonlinearity is weakly scale dependent), we construct an analog of Wilson's epsilon expansion and IR fixed points, with epsilon now set by the scaling of the interaction rather than the spacetime dimension. In the language of RG flow, critical balance scaling -- having applications in fields as varied as astrophysics and ocean waves -- corresponds to the state dynamically adjusting itself along the RG flow until the interaction becomes marginal. (11:10 AM - 12:30 PM, Warren Weaver Hall, Room 1302)
05/09/2025Hep-Th Discussion SessionCalkins [ + ]
05/14/2025Informal HEP TalkSebastian Ellis [ + ]
05/14/2025HEP Journal Club [ + ]
05/14/2025Informal HEP TalkZach Weiner [ + ]
05/16/2025Informal HEP TalkSoichiro Shimamori [ + ]
09/11/2025Physics Dept ColloquiumWendy Freeman [ + ]