Unveiling Vacuum Fluctuations and Nonclassical States with Cavity-Enhanced Tripartite Interactions

Enhancing and tailoring light-matter interactions offer remarkable nonlinear resources with wide-ranging applications in various scientific disciplines. In this study, we investigate the construction of strong and deterministic tripartite `beamsplitter' (`squeeze') interactions by utilizing cavity-enhanced nonlinear anti-Stokes (Stokes) scattering within the spin-photon-phonon degrees of freedom. We explore the exotic dynamical and steady-state properties associated with the confined motion of a single atom within a high-finesse optical cavity. Notably, we demonstrate the direct extraction of vacuum fluctuations of photons and phonons, which are inherent in Heisenberg's uncertainty principle, without requiring any free parameters. Moreover, our approach enables the realization of high-quality single-quanta sources with large average photon (phonon) occupancies. The underlying physical mechanisms responsible for generating nonclassical quantum emitters are attributed to decay-enhanced single-quanta blockade and the utilization of long-lived motional phonons, resulting in strong nonlinearity. This work unveils significant opportunities for studying hitherto unexplored physical phenomena and provides novel perspectives on fundamental physics dominated by strong tripartite interactions.Comment: 13 pages, 4 figures + 1 figure

Strong single-photon to two-photon bundles emission in spin-1 Jaynes-Cummings model

The realization of high-quality special nonclassical states beyond strong single atom-cavity coupling regime is a fundamental element in quantum information science. Here, we study the nonclassical photon emission in a single spin-1 atom coupled to an optical cavity with constructing a spin-1 Jaynes-Cummings model. By tuning quadratic Zeeman shift, the energy-spectrum anharmonicity can be significantly enhanced with respect to the dressed-state splitting of well-resolved n-photon resonance largely increased. The photon emission exhibit high-quality single photon and two-photon bundles properties with large photon numbers in the cavity and atom driven cases, respectively. More interestingly, nonclassical optical switching from strong single-photon blockade to two-photon bundles and super-Poissonian photon emission is achieved and highly controllable by light-cavity detuning in the presence of both atom and cavity driven fields. Our proposal not only open up a new avenue for generating high-quality n-photon sources but also provide versatile applications in quantum networks and quantum metrology.Comment: 26 pages, 4 figure

Nonclassical correlated optical multistability at low photon level for cavity electromagnetically induced transparency

We study the nonequilibrium dynamic behaviors in a driven-dissipative single-atom cavity electromagnetically induced transparency. The optical bistability and multistability beyond a Kerr nonlinearity are observed utilizing the optical Stark shift induced strong nonlinearity. We show that the nonequilibrium dynamical phase transition between bistability and multistability is highly tunable by the system parameters in a large parameter region. The first-order dissipative optical bistability (multistability) always corresponds to the photon-bunching quantum statistics, which indicates that the quantum fluctuations and correlations play important roles in nonequilibrium dynamics.Interestingly, bistability and multistability with photon-bunching quantum statistics occurring at extremely low steady-state cavity photon number are observed, even under a very strong cavity driven field. Furthermore, we demonstrate that the unique cavity steady-state solution of the full quantum calculation is excellently consistent with the lowest solution based on the semiclassical mean-field approach in bistability and multistability regimes when the cavity photon number is much less than unity, albeit these nonclassical quantum states should possess strong quantum fluctuations in this parameter regime. Our results pave the way to exploring nonclassical correlated optical multistability in quantum regime, which may bring exciting opportunities for potential applications from quantum information processing to quantum metrology.Comment: 17 pages, 5 figures; To appear in New J. Phy

The Influence of bFGF on the Fabrication of Microencapsulated Cartilage Cells under Different Shaking Modes

Cell encapsulation in hydrogels has been extensively used in cytotherapy, regenerative medicine, 3D cell culture, and tissue engineering. Herein, we fabricated microencapsulated cells through microcapsules loaded with C5.18 chondrocytes alginate/chitosan prepared by a high-voltage electrostatic method. Under optimized conditions, microencapsulated cells presented uniform size distribution, good sphericity, and a smooth surface with different cell densities. The particle size distribution was determined at 150–280 μm, with an average particle diameter of 220 μm. The microencapsulated cells were cultured under static, shaking, and 3D micro-gravity conditions with or without bFGF (basic fibroblast growth factor) treatment. The quantified detection (cell proliferation detection and glycosaminoglycan (GAG)/type II collagen (Col-II)) content was respectively determined by cell counting kit-8 assay (CCK-8) and dimethylmethylene blue (DMB)/Col-II secretion determination) and qualitative detection (acridine orange/ethidium bromide, hematoxylin-eosin, alcian blue, safranin-O, and immunohistochemistry staining) of these microencapsulated cells were evaluated. Results showed that microencapsulated C5.18 cells under three-dimensional microgravity conditions promoted cells to form large cell aggregates within 20 days by using bFGF, which provided the possibility for cartilage tissue constructs in vitro. It could be found from the cell viability (cell proliferation) and synthesis (content of GAG and Col-II) results that microencapsulated cells had a better cell proliferation under 3D micro-gravity conditions using bFGF than under 2D conditions (including static and shaking conditions). We anticipate that these results will be a benefit for the design and construction of cartilage regeneration in future tissue engineering applications