INSTITUTE FOR THEORETICAL AND MATHEMATICAL PHYSICS

Lomonosov Moscow State University

# ITMP Seminar "An Effective Field Theory for Large Oscillons"

3 October 2022

Dear Colleagues,

We are pleased to announce that the next ITMP seminar will be held on Wednesday, Oct 5, 18:00 (Moscow time). It will be held at ITMP with the possibility to join via zoom.

Speaker: Vasily Maslov, ITMP

Title: An Effective Field Theory for Large Oscillons

Abstract: Based on arXiv:2208.04334. We consider oscillons - localized, quasiperiodic, and extremely long-living classical solutions in models with real scalar fields. We develop their effective description in the limit of large size at finite field strength. Namely, we note that nonlinear long-range field configurations can be described by an effective complex field $\psi(t, \mathbf{x})$ which is related to the original fields by a canonical transformation. The action for $\psi$ has the form of a systematic gradient expansion. At every order of the expansion, such an effective theory has a global U(1) symmetry and hence a family of stationary nontopological solitons - oscillons. The decay of the latter objects is a nonperturbative process from the viewpoint of the effective theory. Our approach gives an intuitive understanding of oscillons in full nonlinearity and explains their longevity. Importantly, it also provides reliable selection criteria for models with long-lived oscillons. This technique is more precise in the nonrelativistic limit, in the notable cases of nonlinear, extremely long-lived, and large objects, and also in lower spatial dimensions. We test the effective theory by performing explicit numerical simulations of a (d+1)-dimensional scalar field with a plateau potential.

If you want to join the seminar please register here before 16:00, October 5 here.

If you would like to subscribe to newsletters about ITMP seminars, please, contact seminar@itmp.msu.ru

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