Open Effective Field Theories from Highly Inelastic Reactions

Abstract

The loss of particles due to highly inelastic reactions has previously been taken into account in effective field theories for low-energy particles by adding local anti-Hermitian terms to the effective Hamiltonian. An additional modification is required in the time evolution equation for the density matrix of a multi-particle system. An effective density matrix can be defined by tracing over states containing high-momentum particles produced by the highly inelastic reactions and by a time average that eliminates short-time correlations. The effective density matrix satisfies the Lindblad equation, with local Lindblad operators that are determined by the anti-Hermitian terms in the effective Hamiltonian.

Decay of ultralight axion condensates

“…The results of our paper, "The Lifetime of Axion Stars" [34], have been called into question in recent publications [35,40]. Before discussing this issue in detail, we review the premises of our work.…”

“…Now the questions raised in [35,40] The argument of [35,40] pertaining to the microscopic side (a) is that in the overwhelmingly dominating Born approximation, the process around which the decay process (1.1) is built is…”

“…We turn now to the last critique presented in [35,40], namely that the classical equation of motion for the axion star precludes a linear coupling to a scattering state axion. In [35], the authors write about our previous work [34] as follows:…”

“…Accordingly, the bound axions have an extended momentum distribution as well. In the recent publications [35,40], the authors questioned the validity of the decay mechanism proposed in [34], arguing that momentum is not conserved in (1.1), and that the decay rate through this process is exactly zero by the Optical Theorem. These authors have further suggested that one can show the rate to be zero by the classical equation of motion for the condensate.…”

Renormalization in open quantum field theory. Part I. Scalar field theory

“…1 Second, open relativistic QFTs are very relevant by themselves in heavy ion physics [19][20][21][22] and cosmology [23][24][25][26][27][28][29][30]. Third motivation is to better understand the apparently non-unitary evolution engendered by black holes and to give a quantitative characterization of the information loss.…”