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Latest articles for New Journal of Physics
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Light-modulated 8-Pmmn borophene-based pure crossed Andreev reflection
We investigate the off-resonant circularly polarized light-modulated crossed Andreev reflection (CAR) in an 8-Pmmn borophene-based normal conductor/superconductor/normal conductor junction. When the signs of Fermi energies in two normal regions are opposite, the pure CAR without the local Andreev reflection and the elastic cotunneling occurs. By using the Dirac–Bogoliubov–de Gennes equation and the Blonder–Tinkham–Klapwijk formula, the pure CAR conductance and its oscillation as a function of the junction length and the Fermi energy in the superconducting regions are discussed. It is found that the value of pure CAR conductance peak value and its corresponding value of light-induced gap increase with the increase of incident energy of electron. Furthermore, the valley splitting for the transmitted hole is found due to the presence of tilted velocity of borophene. Our findings are beneficial for designing the high efficiency 8-Pmmn borophene-based nonlocal transistor and nonlocal valley splitter without local and non-entangled processes.
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Resonant solitary states in complex networks
Partially synchronized solitary states occur frequently when a synchronized system of networked oscillators with inertia is perturbed locally. Several asymptotic states of different frequencies can coexist at the same node. Here, we reveal the mechanism behind this multistability: additional solitary frequencies arise from the coupling between network modes and the solitary oscillator’s frequency, leading to significant energy transfer. This can cause the solitary node’s frequency to resonate with a Laplacian eigenvalue. We analyze which network structures enable this resonance and explain longstanding numerical observations. Another solitary state that is known in the literature is characterized by the effective decoupling of the synchronized network and the solitary node at the natural frequency. Our framework unifies the description of solitary states near and far from resonance, allowing to predict the behavior of complex networks from their topology.
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The edge states of one-dimensional spin- 1 2 ...
A hallmark of topological insulators is topologically protected edge states, which are determined by topological invariants defined under Bloch functions. Of course, not all edge states are stable, and they are independent of topological invariants. And in a recent study, it was found that even stable protected gapless edge states cannot be explained by bulk topological invariants in two-dimensional (2D) systems. Motivated by this idea, we carried out a thorough study in one-dimensional (1D) spin- -like noninteracting periodic systems and found that all edge states can be explained by the most compactly supported Wannier-type functions (MCWTFs). All the answers are contained in the flat-band Hamiltonian defined by MCWTFs. Edge states can be obtained by solving special equations using the parameters of MCWTFs. Symmetries are the special solutions of these equations, and we have proved the relationship between zero-energy edge states and symmetry analytically in partial cases, which was only a well-known result in the past. By solving the equations, we also find that not all zero-energy edge states are determined by symmetry, which is beyond the current framework. Through numerical verification, we show that these zero-energy edge states, like those protected by symmetry, are not affected by the energy spectrum of the system, so they are only related to the Bloch functions. We also derive special properties of zero-energy edge states protected by chiral symmetry from the perspective of MCWTFs, which are consistent with the previous literature. Finally, we do a test in the 2D case and find the connection between the Chern number and the Wannier functions. Our results show that compared with topological invariants, the origin of the edge state can be understood more comprehensively from the perspective of Wannier functions.
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Exploring nonlocal correlations in arbitrarily high-dimensional systems
The utilization of higher-dimensional systems holds promise for unveiling novel phenomena and enhancing the efficacy of practical tasks, such as entanglement-based quantum cryptography. However, detecting quantum correlations within qudit systems poses a formidable challenge. In this study, we delve into the intricacies of Bell’s nonlocality within higher-dimensional systems. We introduce a novel correlation function and leverage it to construct a family of Bell inequalities adapted for quantum systems of arbitrary dimensionality. By gauging the probability of local realism violation under random measurements as our primary metric, we explore the relation between pure state entanglement and nonlocality. Our findings align closely with predictions derived from the comprehensive polytope analysis via linear programming methods. While our focus predominantly centers on the two-qudit scenario, our methodology readily extends to the N-partite case, accommodating an arbitrary number of measurements per party.
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Rotation of self-generated electromagnetic fields by the Nernst effect and Righi–Leduc flux during an intense laser interaction with targets
The effect of an external magnetic field on the evolution of the self-generated electromagnetic field during laser ablation is investigated by using the Vlasov–Fokker–Planck simulations. It is found that the self-generated field is rotated and distorted under an external magnetic field, and for highly magnetized plasma, the rotation of the electric field becomes stable after the laser ablation. The theoretical analysis indicates that the rotation and tortuosity are primarily attributed to the advection of the Nernst effect and the Righi–Leduc (RL) flux. The curl of the self-generated field increases with the Hall parameter and reaches a peak at , then it decreases with the continuous increase. As the Hall parameter increases, the RL flux contributes more than 60% to the rotation of the electric field. Furthermore, the distortion of the electric field continues to rotate after the laser ablation due to the cross-gradient Nernst transport. These findings provide theoretical references for the evolution of the self-generated electromagnetic field in laser-driven magnetized plasmas.