Toroidal Transitions in Hydrogenic and Alkali Atoms

• URL: http://arxiv.org/abs/2607.19832v1
• Date: Wed, 22 Jul 2026 07:11:28 GMT
• Title: Toroidal Transitions in Hydrogenic and Alkali Atoms
• Abstract summary: We discuss the technical challenges of observing toroidal coupling in atomic physics.<n>We show that toroidal transition should be searched in transitions with low principal quantum numbers.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In addition to electric and magnetic multipoles, the expansion of current density also yields toroidal terms, a lesser-known family of multipoles. A recent proposal, I. Kuprov $\textit{et al.}$, Science Adv. 8 abq6751 (2022), explores the possibility of a direct observation of optical toroidal transitions in hydrogen and alkali atoms in the presence of a large magnetic field that decouples the spin and the angular momentum of the electron. However, the difficulty of observing these transitions against the nearby electric dipole (E1) transitions were underestimated because of extra admixture coming from diamagnetic coupling. Here, we revisit the toroidal coupling in atoms, taking diamagnetic contribution into account, and discuss the technical challenges of observing toroidal coupling in atomic physics. We show that toroidal transition should be searched in transitions with low principal quantum numbers. The remaining strong electric-dipole contribution could be removed using an appropriate differential measurement.

Related papers

• Non-Relativistic Quantum Electrodynamics of Atoms in a Rotating Ring Cavity [0.0]
  We derive a quantum optics model in a non-inertial rotating ring cavity from first principles.<n>We find additional terms from the rotation of the system including a rotation-induced hyperfine shift.
  arXiv  Detail & Related papers  (2026-08-04T17:55:53Z)
• Polarization dependence of spin-electric transitions in molecular exchange qubits [0.0]
  We compute the polarizations required for electric- and magnetic-dipole induced transitions through spin-Hamiltonian models of molecular spin triangles.<n>We show that the polarization allows a clear discrimination between the two kinds of transitions.<n>In addition, it allows one to identify the physical origin of the zero-field splitting in the ground multiplet.
  arXiv  Detail & Related papers  (2025-10-03T15:27:36Z)
• Unveiling the Quantum Toroidal Dipole [41.99844472131922]
  We present a complete quantum-mechanical formalism for the TD in a nanostructure.<n>We propose the first spectroscopic method for its direct measurement.<n>This provides a clear experimental blueprint to unveil, measure, and characterize this elusive third multipole moment.
  arXiv  Detail & Related papers  (2024-01-26T13:31:32Z)
• Thermal masses and trapped-ion quantum spin models: a self-consistent approach to Yukawa-type interactions in the $λ\!φ^4$ model [44.99833362998488]
  A quantum simulation of magnetism in trapped-ion systems makes use of the crystal vibrations to mediate pairwise interactions between spins. These interactions can be accounted for by a long-wavelength relativistic theory, where the phonons are described by a coarse-grained Klein-Gordon field. We show that thermal effects, which can be controlled by laser cooling, can unveil this flow through the appearance of thermal masses in interacting QFTs.
  arXiv  Detail & Related papers  (2023-05-10T12:59:07Z)
• Spin Current Density Functional Theory of the Quantum Spin-Hall Phase [59.50307752165016]
  We apply the spin current density functional theory to the quantum spin-Hall phase. We show that the explicit account of spin currents in the electron-electron potential of the SCDFT is key to the appearance of a Dirac cone.
  arXiv  Detail & Related papers  (2022-08-29T20:46:26Z)
• Toroidal optical transitions in hydrogen-like atoms [0.0]
  We show that interactions between light and matter also involve toroidal multipoles. We show that toroidal transitions are odd under parity and time-reversal symmetries.
  arXiv  Detail & Related papers  (2022-05-03T10:55:25Z)
• Relativistic aspects of orbital and magnetic anisotropies in the chemical bonding and structure of lanthanide molecules [60.17174832243075]
  We study the electronic and ro-vibrational states of heavy homonuclear lanthanide Er2 and Tm2 molecules by applying state-of-the-art relativistic methods. We were able to obtain reliable spin-orbit and correlation-induced splittings between the 91 Er2 and 36 Tm2 electronic potentials dissociating to two ground-state atoms.
  arXiv  Detail & Related papers  (2021-07-06T15:34:00Z)
• Chemical tuning of spin clock transitions in molecular monomers based on nuclear spin-free Ni(II) [52.259804540075514]
  We report the existence of a sizeable quantum tunnelling splitting between the two lowest electronic spin levels of mononuclear Ni complexes. The level anti-crossing, or magnetic clock transition, associated with this gap has been directly monitored by heat capacity experiments. The comparison of these results with those obtained for a Co derivative, for which tunnelling is forbidden by symmetry, shows that the clock transition leads to an effective suppression of intermolecular spin-spin interactions.
  arXiv  Detail & Related papers  (2021-03-04T13:31:40Z)
• Photon Condensation and Enhanced Magnetism in Cavity QED [68.8204255655161]
  A system of magnetic molecules coupled to microwave cavities undergoes the equilibrium superradiant phase transition. The effect of the coupling is first illustrated by the vacuum-induced ferromagnetic order in a quantum Ising model. A transmission experiment is shown to resolve the transition, measuring the quantum electrodynamical control of magnetism.
  arXiv  Detail & Related papers  (2020-11-07T11:18:24Z)
• From megahertz to terahertz qubits encoded in molecular ions: theoretical analysis of dipole-forbidden spectroscopic transitions in N$\mathbf{_2^+}$ [0.0]
  We study theoretically the implementation of qubits and clock transitions in the spin, rotational, and vibrational degrees of freedom of molecular ions. We identify two types of magnetically insensitive qubits with very low ("stretched"-state qubits) or even zero ("magic" magnetic-field qubits) linear Zeeman shifts. We explore possibilities to coherently control the nuclear-spin configuration of N$+$ through the magnetically enhanced mixing of nuclear-spin states.
  arXiv  Detail & Related papers  (2020-07-21T21:24:13Z)
• Quantum coherent spin-electric control in a molecular nanomagnet at clock transitions [57.50861918173065]
  Electrical control of spins at the nanoscale offers architectural advantages in spintronics. Recent demonstrations of electric-field (E-field) sensitivities in molecular spin materials are tantalising. E-field sensitivities reported so far are rather weak, prompting the question of how to design molecules with stronger spin-electric couplings.
  arXiv  Detail & Related papers  (2020-05-03T09:27:31Z)
• Optimal coupling of HoW$_{10}$ molecular magnets to superconducting circuits near spin clock transitions [85.83811987257297]
  We study the coupling of pure and magnetically diluted crystals of HoW$_10$ magnetic clusters to microwave superconducting coplanar waveguides. Results show that engineering spin-clock states of molecular systems offers a promising strategy to combine sizeable spin-photon interactions with a sufficient isolation from unwanted magnetic noise sources.
  arXiv  Detail & Related papers  (2019-11-18T11:03:06Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.