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Probing exciton/exciton interactions with entangled photons: Theory
摘要： Quantum entangled photons provide a sensitive probe of many-body interactions and offer a unique experimental portal for quantifying many-body correlations in a material system. In this paper, we present a theoretical demonstration of how photon–photon entanglement can be generated via interactions between coupled qubits. Here, we develop a model for the scattering of an entangled pair of photons from a molecular dimer. We develop a diagrammatic theory for the scattering matrix and show that one can correlate the von Neumann entropy of the outgoing bi-photon wave function with exciton exchange and repulsion interactions. We conclude by discussing possible experimental scenarios for realizing these ideas.
关键词： exciton exchange,repulsion interactions,quantum entangled photons,von Neumann entropy,many-body interactions
更新于2025-09-23 15:19:57
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Crossover from positive to negative optical torque in mesoscale optical matter
摘要： The photons in circularly polarized light can transfer their quantized spin angular momentum to micro- and nanostructures via absorption and scattering. This normally exerts positive torque on the objects where the sign (i.e., handedness or angular direction) follows that of the spin angular momentum. Here we show that the sign of the optical torque can be negative in mesoscopic optical matter arrays of metal nanoparticles (NPs) assembled in circularly polarized optical traps. Crossover from positive to negative optical torque, which occurs for arrays with different number, separation and configuration of the constituent particles, is shown to result from many-body interactions as clarified by electrodynamics simulations. Our results establish that both positive and negative optical torque can be readily realized and controlled in optical matter arrays. This property and reconfigurability of the arrays makes possible programmable materials for optomechanical, microrheological and biological applications.
关键词： mesoscale optical matter,many-body interactions,metal nanoparticles,electrodynamics simulations,optical torque
更新于2025-09-11 14:15:04
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Element- and Site-Specific Many-Body Interactions in Few-Layer MoS <sub/>2</sub> During X-Ray Absorption Processes
摘要： Few-layer MoS2 is a promising 2D material for nano-electronic device applications. However, the performance of these devices is often deteriorated. One of the reasons is that the electronic properties are influential to the many-body effects such as excitonic effects and Anderson orthogonality catastrophe (AOC) which could renormalize the band-dispersion and density-of-states(DOS). Hence, the authors investigate the effect of many-body interactions on MoS2 device performance by using X-ray absorption spectro-microscopy (m-XAS) on a few-layer MoS2 transistor in operation, through the application of gate-bias or contact with a metal. The results show a significant peak shift in m-XAS spectra while varying the gate-bias. The applied negative gate-bias induces more holes which attracts excited electrons resulting strong many-body interactions followed by Fermi level shift. This effect is discussed with the aid of XAS-Auger electron phenomena. However, the AOC contribution in XAS peak-intensity is ignored since the bands around the energy-gap in MoS2 are relatively flat and the DOS is empty above Fermi level (unlike graphene). The authors observe a redshift in photon energy near the MoS2/metal-electrode interface due to charge transfer ensuring carrier-doping induced through metal-contact. These observations provide significant insight into element- and site-specific many-body interactions in MoS2 tunable by gate-bias or contact with a metal.
关键词： many-body interactions,element- and site-specific,MoS2,X-ray absorption spectromicroscopy
更新于2025-09-04 15:30:14