相关实验视频
Updated: Mar 7, 2026

06:42
Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
9.8K
通过量子相位过渡产生决定性纠
Xin-Yu Luo1, Yi-Quan Zou1, Ling-Na Wu1
1State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China. lyou@mail.tsinghua.edu.cn mengkhoon_tey@mail.tsinghua.edu.cn.
概括
研究人员使用量子相位过渡创建了一个大规模的纠双福克凝聚物. 这种方法为先进的量子技术产生有用的纠提供了强大的方法.
科学领域:
- 量子物理学
- 原子物理
- 多体系统
背景情况:
- 多体纠对于量子技术至关重要,
- 非线性相互作用可以产生纠,但也会导致退化.
- 控制量子动力学是利用纠的关键.
研究的目的:
- 为了证明大规模纠双福克凝聚物的近确定性生成.
- 利用量子相位转换 (QPT) 来实现强大的纠.
- 量化产生的纠及其潜在应用.
主要方法:
- 在-87波斯-爱因斯坦凝聚物中进行旋转混合.
- 使用两个连续的量子相位过渡 (QPT).
- 直接观察数量挤压和集体旋转长度.
主要成果:
- 产生约11000个原子的纠双福克凝聚物.
- 观察到数量挤压为10.7 ± 0.6分贝.
- 测量正常化的集体旋转长度为0.99±0.01.
- 超出标准量子极限 (~6dB) 的推断纠增强相位灵敏度.
- 确定了大约910个原子的纠宽度.
结论:
- 量子相变提供了一个强大的工具来产生大规模的,有用的纠.
- 展示的方法提供了一种克服纠退化的途径.
- 这项工作促进了量子传感和计算的纠状态的创建.
相关概念视频
Carrier Generation and Recombination
1.4K
Carrier generation is the process by which electron-hole pairs (EHPs) are created within the semiconductor. In direct-bandgap semiconductors, such as gallium arsenide (GaAs), this occurs efficiently when energy absorption prompts valence electrons to leap into the conduction band, leaving behind holes.
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
1.4K
The Entropy as a State Function
21
Consider an arbitrary process that moves between two specific states (A and B) in a cyclic manner. This process is reversible and broken down into smaller parts that each follow a Carnot cycle. A Carnot cycle has two isothermal (constant temperature) processes. During these processes, the ratio of the amount of heat transferred to their respective temperature remains constant. The other two processes in the Carnot cycle are also reversible but adiabatic, which means they occur without any heat...
21
Entropy Change in Reversible Processes
3.3K
In the Carnot engine, which achieves the maximum efficiency between two reservoirs of fixed temperatures, the total change in entropy is zero. The observation can be generalized by considering any reversible cyclic process consisting of many Carnot cycles. Thus, it can be stated that the total entropy change of any ideal reversible cycle is zero.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
3.3K
Phase Transitions
27
A phase transition is the process in which a substance changes from one state of matter to another, like from a solid to a liquid, liquid to gas, or vice versa, at a specific temperature and under given pressure conditions. This change is spontaneous and is affected by alterations in temperature and pressure. These parameters impact the strength of the forces between molecules (intermolecular forces) in the substance.During a phase transition, both the initial and final phases of the substance...
27
Phase Transitions
23.5K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.5K
Woodward–Hoffmann Selection Rules and Microscopic Reversibility
4.1K
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
4.1K

