- 标题
- 摘要
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- 实验方案
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Quantum computing with neutral atoms
摘要： The power of quantum computation derives from algorithmic methods that exploit the availability of quantum superposition and entanglement to perform computations that are intractable with classical devices. The race is on to develop hardware that will unleash the promise of quantum algorithms. A handful of different types of hardware are currently being developed with the greatest efforts directed at superconducting, quantum-dot, trapped-ion, photonic, and neutral-atom approaches [1]. While all approaches have strengths and weaknesses, and are at different stages of development, the challenge of creating a practical design that can be scaled to a million or more qubits has not yet been met with any of the existing platforms.
关键词： neutral atoms,Rydberg states,Quantum computing,quantum error correction,qubits
更新于2025-09-23 15:21:21
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A single-laser alternating-frequency magneto-optical trap
摘要： In this paper, we present a technique for magneto-optical cooling and trapping of neutral atoms using a single laser. The alternating-frequency magneto-optical trap (AF-MOT) uses an agile light source that sequentially switches between cooling and repumping transition frequencies by tuning the injection current of the laser diode. We report on the experimental demonstration of such a system for 87Rb and 85Rb based on a microintegrated extended cavity diode laser performing laser frequency jumps of up to 6.6 GHz with a tuning time in the microsecond regime and a repetition rate of up to 7.6 kHz. For that, a combination of a feed-forward for coarse frequency control and a feedback for precise locking was used. We discuss the results of the AF-MOT characterization in terms of atom numbers and cloud temperature for different operation parameters.
关键词： alternating-frequency,single-laser,neutral atoms,cooling and trapping,magneto-optical trap
更新于2025-09-11 14:15:04
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In situ measurement of the spectral reflectance of mirror-like metallic surfaces during plasma exposition
摘要： Visible spectroscopy in fusion plasmas crucially depends on the optical properties of first mirrors withstanding a considerable amount of radiation and particle fluxes. As a result of this interaction the optical properties of the mirrors could be changed so that a cleaning of the mirror is regularly required. Thus the reflectance of the first mirror must be monitored in situ. The newly developed Doppler-Shifted Reflectance Measurement (DSRM) diagnostic provides the spectral reflectance of mirrors in the absence of any calibration sources. It is based on the emission of fast H/D atoms in a low density Ar-H plasma by applying a negative potential on the order of to the mirror surface. Until now, the experimental data were restricted to measure only the fast atoms emission at the Hα line. In this work we prove that the new technique also provides the mirror reflectance at the Hβ line (Cu) (486 nm) relevant for the charge-exchange recombination spectroscopy (CXRS) measurements of the He II line (468 nm) in ITER. Moreover, the DSRM diagnostic remains sensitive to the polarization of the reflected light of a W mirror. We present the first experimental data on the time-dependent regime of operation: in situ monitoring of the degradation of an Al mirror is shown as a function of the mirror temperature. The passive heating of the mirror was performed by the plasma itself, which makes the separation between the impact of high temperature and plasma erosion on the mirror reflectance for the temperatures above 500 K impossible. A very good agreement of the experimental and the theoretical data calculated using the Drude theory for the temperature below 500 K is found. For the temperatures above 500 K the degradation of the reflectance of the mirror is determined by the erosion of Al, which is confirmed by monitoring the Al I spectral lines in unison.
关键词： light polarization,CXRS,surface degradation,optical emission spectroscopy,fast neutral atoms,spectral reflectance
更新于2025-09-10 09:29:36