16,401 research outputs found
Single-photon transport in a one dimentional waveguide coupling to a hybrid atom-optomechanical system
We explore theoretically the single-photon transport in a single-mode
waveguide that is coupled to a hybrid atom-optomechanical system in a strong
optomechanical coupling regime. Using a full quantum real-space approach,
transmission and reflection coefficients of the propagating single-photon in
the waveguide are ob- tained. The influences of atom-cavity detuning and the
dissipation of atom on the transport are also studied. Intriguingly, the
obtained spectral features can reveal the strong light-matter interaction in
this hybrid system.Comment: 7pages, 8figure
Tunable one-dimensional microwave emissions from cyclic-transition three-level atoms
By strongly driving a cyclic-transition three-level artificial atom,
demonstrated by such as a flux-based superconducting circuit, we show that
coherent microwave signals can be excited along a coupled one-dimensional
transmission line. Typically, the intensity of the generated microwave is
tunable via properly adjusting the Rabi frequencies of the applied
strong-driving fields or introducing a probe field with the same frequency. In
practice, the system proposed here could work as an on-chip quantum device with
controllable atom-photon interaction to implement a total-reflecting mirror or
switch for the propagating probe field.Comment: 4 pages, 5 figure
Gain without inversion in quantum systems with broken parities
For a quantum system with broken parity symmetry, selection rules can not
hold and cyclic transition structures are generated. With these
loop-transitions we discuss how to achieve inversionless gain of the probe
field by properly setting the control and auxiliary fields. Possible
implementations of our generic proposal with specific physical objects with
broken parities, e.g., superconducting circuits and chiral molecules, are also
discussed.Comment: 12 pages, 4 figure
Vacuum induced Berry phases in single-mode Jaynes-Cummings models
Motivated by the work [Phys. Rev. Lett. 89, 220404 (2002)] for detecting the
vacuum-induced Berry phases with two-mode Jaynes-Cummings models (JCMs), we
show here that, for a parameter-dependent single-mode JCM, certain atom-field
states also acquire the photon-number-dependent Berry phases after the
parameter slowly changed and eventually returned to its initial value. This
geometric effect related to the field quantization still exists, even the filed
is kept in its vacuum state. Specifically, a feasible Ramsey interference
experiment with cavity quantum electrodynamics (QED) system is designed to
detect the vacuum-induced Berry phase.Comment: 10 pages, 4 figures
Atom-photon dressed states in a waveguide-QED system with multiple giant atoms coupled to a resonator-array waveguide
We study the properties of bound and scattering states in the
single-excitation subspace in waveguide-QED systems consisting of multiple
giant atoms coupled to a coupled-resonator waveguide. Based on the most general
analytical expressions possible for these states and the corresponding energy
spectra, we analyze in detail relevant phenomena due to the influence of a
structured environment combined with the non-dipole effects of giant atoms. We
analyze the threshold conditions for the appearance of bound states and the
photon-mediated interactions between dressed atoms for different
configurations. In addition, when multiple giant atoms are coupled to the
waveguide, the bound states in the photonic band gaps can form different types
of metaband structures, depending on coupling configurations. This makes the
system a useful platform for quantum simulations. Finally the influence of the
structured bath on the scattering spectra of multiple atoms also becomes
remarkable in the strong coupling regime, leading to unconventional spectral
structures.Comment: 24 pages, 12 figure
Research on UBI auto insurance pricing model based on parameter adaptive SAPSO optimal fuzzy controller
Aiming at the problem of “dynamic” accurate determination of rates in UBI auto insurance pricing, this paper proposes a UBI auto insurance pricing model based on fuzzy controller and optimizes it with a parameter adaptive SASPO. On the basis of the SASPO algorithm, the movement direction of the particles can be mutated and the direction can be dynamically controlled, the inertia weight value is given by the distance between the particle and the global optimal particle, and the learning factor is calculated according to the change of the fitness value, which realizes the parameter in the running process. Effective self-adjustment. A five-dimensional fuzzy controller is constructed by selecting the monthly driving mileage, the number of violations, and the driving time at night in the UBI auto insurance data. The weights are used to form fuzzy rules, and a variety of algorithms are used to optimize the membership function and fuzzy rules and compare them. The research results show that, compared with other algorithms, the parameter adaptive SAPAO algorithm can calculate more reasonable, accurate and high-quality fuzzy rules and membership functions when processing UBI auto insurance data. The accuracy and robustness of UBI auto insurance rate determination can realize dynamic and accurate determination of UBI auto insurance rates
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Rapid RNA Exchange in Aqueous Two-Phase System and Coacervate Droplets
Compartmentalization in a prebiotic setting is an important aspect of early cell formation and is crucial for the development of an artificial protocell system that effectively couples genotype and phenotype. Aqueous two-phase systems (ATPSs) and complex coacervates are phase separation phenomena that lead to the selective partitioning of biomolecules and have recently been proposed as membrane-free protocell models. We show in this study through fluorescence recovery after photobleaching (FRAP) microscopy that despite the ability of such systems to effectively concentrate RNA, there is a high rate of RNA exchange between phases in dextran/polyethylene glycol ATPS and ATP/poly-L-lysine coacervate droplets. In contrast to fatty acid vesicles, these systems would not allow effective segregation and consequent evolution of RNA, thus rendering these systems ineffective as model protocells. Electronic supplementary material The online version of this article (doi:10.1007/s11084-014-9355-8) contains supplementary material, which is available to authorized users
Effect of finishing rolling reduction on microstructures and textures of grain oriented silicon steel
The effect of finishing rolling reduction on microstructures and textures of grain oriented silicon steel was researched by optical microscopy, zeiss ultra 55 Scanning Electron Microscope (SEM) and Electron Backscatter Diffraction (EBSD) technique severally. The results show that the grain size of hot rolled sheets and decarburized strips decreases, while the center grain size of the normalized sheet increases with the increase of the finishing rolling reduction. The pearlite content increases with the increase of the finishing rolling reduction after normalization. Compare with the previous research, the effect of finishing rolling reduction on the grain size of primary recrystallization is greater than that of roughing rolling reduction, and large rolling reduction is beneficial to the formation of {110} texture
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