Knowing when a physical system has reached sufficient size for its macroscopic properties to be well described by many-body theory is difficult. We investigated the crossover from few- to many-body physics by studying quasi-one-dimensional systems of ultracold atoms consisting of a single impurity interacting with an increasing number of identical fermions. We measured the interaction energy of such a system as a function of the number of majority atoms for different strengths of the interparticle interaction. As we increased the number of majority atoms one by one, we observed fast convergence of the normalized interaction energy toward a many-body limit calculated for a single impurity immersed in a Fermi sea of majority particles.
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http://dx.doi.org/10.1126/science.1240516 | DOI Listing |
J Colloid Interface Sci
January 2025
School of Materials Science and Engineering, State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan 570228, China. Electronic address:
Emerging of the lattice oxygen mechanism (LOM) provides a new opportunity for enhancing oxygen evolution reaction (OER) activity. However, its stability suffers from metal cation dissolution and lattice oxygen anionic redox chemistry. In this paper, carbon dots (CDs)-modified nickel-iron MOF (Metal-Organic Framework) nanosheets (NiFe-BDC/CDs) were prepared for efficient OER electrocatalysis.
View Article and Find Full Text PDFEur Phys J B
January 2025
Department of Physics "A. Pontremoli", University of Milan, Via Celoria 16, 20133 Milan, Italy.
Abstract: Quantum rings have emerged as a playground for quantum mechanics and topological physics, with promising technological applications. Experimentally realizable quantum rings, albeit at the scale of a few nanometers, are 3D nanostructures. Surprisingly, no theories exist for the topology of the Fermi sea of quantum rings, and a microscopic theory of superconductivity in nanorings is also missing.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
Fermi polarons are emerging quasiparticles when a bosonic impurity immersed in a fermionic bath. Depending on the boson-fermion interaction strength, the Fermi-polaron resonances exhibit either attractive or repulsive interactions, which impose further experimental challenges on understanding the subtle light-driven dynamics. Here, we report the light-driven dynamics of attractive and repulsive Fermi polarons in monolayer WSe devices.
View Article and Find Full Text PDFIn doped semiconductors such as monolayer transition-metal dichalcogenides (TMDs), the optical properties are predominantly determined by exciton polarons, which are coherent superpositions of excitons and electron-hole excitation pairs in the Fermi sea. Here, we theoretically study the effect of exciton polarons on thermal radiation in doped two-dimensional semiconductors. By deriving an emissivity formula in terms of the dielectric function and the thickness of two-dimensional semiconductors, we show that the emissivity spectrum exhibits a narrow peak at the energy of an exciton polaron.
View Article and Find Full Text PDFNanophotonics
February 2024
Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland.
We present femtosecond pump-probe measurements of neutral and charged exciton optical response in monolayer MoSe to resonant photoexcitation of a given exciton state in the presence of 2D electron gas. We show that creation of charged exciton (X) population in a given K, K valley requires the capture of available free carriers in the opposite valley and reduces the interaction of neutral exciton (X) with the electron Fermi sea. We also observe spectral broadening of the X transition line with the increasing X population caused by efficient scattering and excitation induced dephasing.
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