In molecules at surface, the interaction between molecule and substrate gives rise to novel magnetic properties. The Kondo effect and zero-field splitting induced by spin-orbit interaction are representative ones. In this article, we review recent progress of this field and give future prospect.

Cavity quantum electrodynamics has been developed to control quantum systems by strengthening the coupling between matters and electromagnetic fields. By looking at various metaphors that emerged from the Platonic idea of cavity quantum electrodynamics, i.e., the Jaynes-Cummings model, we guide you to the world of cavity magnonics, where magnetism meets quantum optics.

After the discovery of the Higgs boson in 2012, ATLAS experiment at LHC is performing precise measurements to reveal the nature of vacuum. We discuss the first observation of the Higgs boson decaying into bb pair and ttH production. These measurements indicate the Yukawa coupling between the Higgs boson and the third generation quark is consistent with the expectation of the Standard Model. Also, the stability of vacuum based on the latest mass measurement of top quark and W ^± boson is discussed.

The magnetoelectric (ME) effect is a cross correlation between the magnetic and electric properties. We observe an anomalous antiferroelectric behavior induced by non-collinear magnetic quadrupole type order, i.e., two-in, two-out arrangement of spins, in an antiferromagnet Ba (TiO) Cu₄(PO₄)₄ consisting of convex spin clusters Cu₄O₁₂ called square cupolas. We construct a quantum spin model with parameters determined based on full magnetization curves, which also well reproduces all the observed antiferroelectric behaviors. Our results elucidate how the asymmetric square cupola units activate the ME responses through antisymmetric interactions arising from the spin-orbit coupling.

When solids are exposed to intense optical fields, the intraband electron motion may influence interband transitions, potentially causing a transition of light-matter interaction from a quantum (photon-driven) regime to a semi-classical (field-driven) regime. We demonstrate this transition in monolayer graphene. We observe a carrier-envelope-phase-dependent current in graphene irradiated with phase-stable two-cycle laser pulses, showing a striking reversal of the current direction as a function of the driving field amplitude at ～2 V/nm. This reversal indicates the transition into the field-driven (or strong-field) regime. We show furthermore that in this regime electron dynamics are governed by sub-optical-cycle Landau-Zener-Stückelberg interference, comprised of coherent repeated Landau-Zener transitions. We expect these results to have direct ramifications for light-field-driven electronics in graphene.