The Schr\"odinger equation for a charged particle in the field of a nonrelativistic electric quadrupole in two dimensions is known to be separable in spherical coordinates. We investigate the occurrence of bound states of negative energy and find that the particle can be bound by a quadrupole of any magnitude. This result is remarkably different from the one for a charged particle in the field of a nonrelativistic electric dipole in three dimensions where a minimum value of the dipole strength is necessary for capture. Present results differ from those obtained earlier by other author.
Bound states of massive fermions in the Aharonov--Bohm-like fields
Interference traps waves in open system: Bound states in the continuum
Investigating the quench dynamics of the bound states in a spin-orbital coupling system using a trapped ion
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