C. H. Oh

In this work, the absorption spectrum of a two-level ion in a linear Paul trap is investigated, the ion is supposed to be driven by two orthogonal laser beams, the one along the axial of the trap acts as the control light beam, the other as probe beam. When the frequency of the control laser is tuned to the first red sideband of the ionic transition, the coupling between the internal states of the ion and vibrational mode turns out to be a Jaynes-Cummings (JC) Hamiltonian, which together with the coupling between the probe beam and the two-level ion constructs a Λ-type three-level structure. In this case the transparency window may appear in the absorption spectrum of the probe light, which is induced by the ionic vibration and is very similar to the cavity induced transparency [1996 Opt. Commun. 126 230-235]. On the other hand, when the frequency of the control laser is tuned to the first blue sideband of the ionic transition, the two-level ion and vibrational mode are governed by an anti-Jaynes-Cummings (anti-JC) Hamiltonian, the total system including the probe beam forms a V -type threelevel structure. And the Autler-Townes splitting in the absorption spectrum is found.

The existence of minimal length scale has motivated the proposal of generalized uncertainty principle, which provides a potential routine to probe quantum gravitational effects in low-energy quantum mechanics experiment. Hitherto, the tabletop experiment of testing deviations from ordinary quantum mechanics are mostly based on microscopic objects. However, the feasibility of these studies are challenged by the recent study of spacetime quantization for composite macroscopic body. In this paper, we propose a scheme to probe quantum gravity effects by revealing the deviations from predictions of Heisenberg uncertainty principle. Our scheme focus on manipulating the interaction sequences between external laser fields and a single trapped ion to seek evidence of spacetime quantization, therefore reduce the complicity induced by large bodies to some extent. The relevant study for microscopic particles is crucial considering the lack of satisfactory theories regarding basic properties for multi-particles in the framework of quantum gravity. Meanwhile, we are managed to set a new upper limit for deformation parameter.

In comparison with entanglement and Bell nonlocality, Einstein-Podolsky-Rosen steering is a newly emerged research topic and in its incipient stage. Although Einstein-Podolsky-Rosen steering has been explored via violations of steering inequalities both theoretically and experimentally, the known inequalities in the literatures are far from well-developed. As a result, it is not yet possible to observe Einstein-Podolsky-Rosen steering for some steerable mixed states. Recently, a simple approach was presented to identify Einstein-Podolsky-Rosen steering based on all-versus-nothing argument, offering a strong condition to witness the steerability of a family of two-qubit (pure or mixed) entangled states. In this work, we show that the all-versus-nothing proof of Einstein-Podolsky-Rosen steering can be tested by measuring the projective probabilities. Through the bound of probabilities imposed by local-hidden-state model, the proposed test shows that steering can be detected by the all-versus-nothing argument experimentally even in the presence of imprecision and errors. Our test can be implemented in many physical systems and we discuss the possible realizations of our scheme with non-Abelian anyons and trapped ions.

Synthetic spin-orbit coupling (SOC) in controlled quantum systems such as cold atoms or trapped ions has been of great interest. Here we show, both theoretically and computationally, a simplest realization of SOC using two-level cold atoms interacting with only one laser beam. The underlying mechanism is based upon the non-adiabatic nature of laser-atom interaction, with the Rabi frequency and atom's kinetic energy being comparable to each other. We use the Zitterbewegung (ZB) oscillation to further illustrate the effects of the synthesized SOC on the quantum dynamics of the two-level cold atoms. We expect our proposal to be of experimental interest in quantum simulation of SOC-related physics.

Zitterbewegung oscillation (ZB), namely, the jittering center-of-mass motion predicted by free space Dirac (or Dirac-like) equations, has been studied in several different contexts. It is shown here that ZB can be converted to directed center-of-mass motion by a modulation of the Dirac-like equation, if the modulation is on resonance with the ZB frequency. Tailored modulation may also stop, re-launch or even reverse the directed motion of a wavepacket with negligible distortion. The predictions may be examined by current ZB experiments using trapped-ion systems.