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Journal of Physics B: Atomic, Molecular and Optical Physics - latest papers

Latest articles for Journal of Physics B: Atomic, Molecular and Optical Physics

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  • Misalignment of optical and rotational axis in rotational Doppler effect
    The interaction of an incoming beam carrying orbital angular momentum with a rotating body leads to a rotational Doppler shift in the frequency of the outgoing or scattered beam. This shift reveals the characteristics of the rotation. When the axes of the beam and the rotation are not aligned, harmonics appear in the frequency spectrum. Numerical simulations show that these harmonics originate from the modal decomposition of the incident beam into a Laguerre–Gaussian basis attached to the rotating system. The cases of lateral displacement and skew angle are considered both separately and together. The consequences for practical determination of the rotation frequency and the location of the rotation axis are then discussed.

  • EUV photoabsorption investigations of zirconium ions using the dual laser plasma technique
    Employing the dual laser plasma technique, the extreme ultraviolet photoabsorption spectra of Zr3+, Zr4+ and Zr5+ spanning the energy range from 58 to 230 eV were measured with an energy resolution of . The measured spectra are carefully analyzed by comparing with the available reference data and theoretical calculation using the fully relativistic multi-configuration Dirac–Fock method. The identified Rydberg series include 4s np transitions in Zr3+, 4p ns/nd, 4s np and double excitations of 4p6 4p44dnp in Zr4+, 4s np transitions in Zr5+, as well as 3d np/nf transitions of these three Zr ions. The reported experimental data of zirconium ions contribute to the fundamental atomic database, offering valuable benchmarks for theoretical calculations with potential applications in astrophysics and plasma sciences.

  • Quantum Otto engine powered by two-spin Heisenberg chain with Zeeman energy and symmetric cross spin
    This paper proposes a theoretical model for a heat engine operating on the Otto cycle, employing a two-qubit Heisenberg chain as its working substance. This system is subjected to an external, time-dependent homogeneous magnetic field and a symmetric cross-spin interaction. The interaction is configured to occur along two distinct orientations, contingent upon the direction of Zeeman energy and symmetric interaction: either exclusively along the X-direction or exclusively along the Z-direction. Furthermore, the thermal reservoirs integral to the Otto engine are considered to engage with the working substance via two discrete modes: a localized interaction or a collective interaction. The two qubits exhibit weak coupling to a non-equilibrium thermal environment during the isochoric heating and cooling strokes, thereby validating the application of a Markovian model as a suitable approximation for describing the time evolution of the working substance. This study investigates the influence of various system parameters on the thermodynamic quantities and the resultant power output. A principal finding is that refrigeration functionality is the predominant operational characteristic when the system engages in collective interaction with the reservoirs. Conversely, localized interactions facilitate dual operational modes, with the sign of the Zeeman energy determining the function as either a refrigerator or a heat engine. Significantly, positive power output is achieved in the engine regime, and we find that the choice of interaction axis acts as a powerful amplification mechanism for the thermodynamic output, while the system-environment coupling scheme proves to be the most decisive factor in determining the machine’s fundamental purpose.

  • Atomic flow driven by superradiance and particle pumping in an incommensurate optical lattice
    This work studies the non-equilibrium dynamics of polarized fermions in a one-dimensional cavity-assisted hopping lattice with an incommensurate potential. By employing the Keldysh Green’s function method to solve the equations of motion, we demonstrate that both the superradiance and kinetic energy of the atoms are suppressed if we tune the strength of the incommensurate potential to be large enough. We also find that the right directed current originates from the skin effect, which is derived by two processes: one is the superradiance and the other is the energy pumping of the oscillation of the cavity mode. In addition to these, we also prove the unique characteristics of the steady state in our model. Our work extends the existing study, and combines dynamic gauge coupling with the incommensurate optical lattice. These innovative findings provide new research directions for future experimental observations and have important potential application values.

  • Enhanced entanglement of a two-mode squeezed vacuum state via a state-projective operation and a phase measurement
    This paper aims to substantially enhance the entanglement of the two-mode squeezed vacuum state (TMSVS) by proposing a new state engineered through a sequential application of a state-projective operation followed by a phase measurement (PM). This construction exploits a laser field modeled as a coherent state of moderately strong amplitude, thereby compensating for the limited squeezing achievable in practice. Remarkably, the resulting state achieves entanglement, quantified by the von Neumann entropy, exceeding 3.45 even for moderate squeezing ( ), whereas it remains below 1.22 for the TMSVS. In addition, we show that the state can teleport a coherent state with an average fidelity exceeding 99%. Finally, we propose an optical scheme for generating the new state. In addition to the PM element, the scheme employs three weak cross-Kerr nonlinear media, two beam splitters, and a nonideal on-off photodetector. The proposed state can be utilized for quantum information processing, particularly in continuous-variable quantum circuits involving entanglement.