English

Spectral deformation for two-body dispersive systems with e.g. the Yukawa potential

Mathematical Physics 2016-12-21 v3 math.MP

Abstract

We find an explicit closed formula for the kk'th iterated commutator adAk(HV(ξ))\mathrm{ad}_A^k(H_V(\xi)) of arbitrary order k1k\ge1 between a Hamiltonian HV(ξ)=Mωξ+SVˇH_V(\xi)=M_{\omega_\xi}+S_{\check V} and a conjugate operator A=i2(vξ+vξ)A=\frac{\mathfrak{i}}{2}(v_\xi\cdot\nabla+\nabla\cdot v_\xi), where MωξM_{\omega_\xi} is the operator of multiplication with the real analytic function ωξ\omega_\xi which depends real analytically on the parameter ξ\xi, and the operator SVˇS_{\check V} is the operator of convolution with the (sufficiently nice) function Vˇ\check V, and vξv_\xi is some vector field determined by ωξ\omega_\xi. Under certain assumptions, which are satisfied for the Yukawa potential, we then prove estimates of the form adAk(HV(ξ))(H0(ξ)+i)1Cξkk!\lVert\mathrm{ad}_A^k(H_V(\xi))(H_0(\xi)+\mathfrak{i})^{-1}\rVert\le C_\xi^kk! where CξC_\xi is some constant which depends continuously on ξ\xi. The Hamiltonian is the fixed total momentum fiber Hamiltonian of an abstract two-body dispersive system and the work is inspired by a recent result [Engelmann-M{\o}ller-Rasmussen, 2015] which, under conditions including estimates of the mentioned type, opens up for spectral deformation and analytic perturbation theory of embedded eigenvalues of finite multiplicity.

Keywords

Cite

@article{arxiv.1509.02066,
  title  = {Spectral deformation for two-body dispersive systems with e.g. the Yukawa potential},
  author = {Matthias Engelmann and Morten Grud Rasmussen},
  journal= {arXiv preprint arXiv:1509.02066},
  year   = {2016}
}