相关实验视频
Updated: Jul 5, 2026

11:21
Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
热化及其对通用孤立量子系统的机制
Marcos Rigol1, Vanja Dunjko, Maxim Olshanii
1Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA.
Nature
|April 19, 2008
概括
孤立的量子多体系统确实进行热化,放松到可预测的状态. 这发生在个体固有状态的水平上,而不仅仅是通过时间进化,证实了固有状态热化假说.
科学领域:
- 量子力学就是量子力学.
- 统计力学就是统计力学.
- 凝聚物质物理学 凝聚物质物理学
背景情况:
- 了解孤立量子系统的时间演变是具有挑战性的.
- 预计一般孤立系统中的非平衡动态将导致热化.
- 量子热化背后的机制,类似于经典动态混乱,尚未完全理解.
研究的目的:
- 为了证明一般的孤立量子多体系统可以放松到由统计力学描述的状态.
- 为了研究时间进化的作用与量子热化中的个体固有状态.
- 为了证实特定量子系统中的固态热化假设.
主要方法:
- 孤立量子多体系统的理论分析.
- 数字模拟 (暗示"为我们的系统确认").
- 从统计力学的预测与系统动态的比较.
主要成果:
- 一般的孤立量子多体系统确实会放松到标准统计力学描述的状态.
- 热化发生在个体固有状态的水平上,时间进化起到次要的作用.
- 在微规范窗口内的单个多体固有状态足以计算热平均值.
结论:
- 固态热化假设为孤立量子系统中的热化提供了强有力的解释.
- 个别的固有状态,而不仅仅是整体的时间进化,决定了热化状态.
- 这一发现简化了量子系统中热平均值的计算.
相关概念视频
Thermodynamic Systems
A thermodynamic system is a set of objects whose thermodynamic properties are of interest. The system is considered to be embedded in its surroundings or the environment. The system and its environment can exchange heat and do work on each other through a boundary that separates them. However, the immediate surroundings of the system interact with it directly and therefore have a much stronger influence on its behavior and properties.
Consider an example of tea boiling in a kettle. The tea and...
Consider an example of tea boiling in a kettle. The tea and...
Isothermal Processes
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
Zeroth Law of Thermodynamics
Experimentally, if object A is in equilibrium with object B, and object B is in equilibrium with object C, then object A is in equilibrium with object C. That statement of transitivity is called the "zeroth law of thermodynamics." For example, a cold metal block and a hot metal block are both placed on a metal plate at room temperature. Eventually, the cold block and the plate will be in thermal equilibrium. In addition, the hot block and the plate will be in thermal equilibrium. By the zeroth...
Entropy and the Second Law of Thermodynamics
Consider an isolated system in which a hot object is placed in contact with a cold one. This is an irreversible process that eventually leads both objects to reach the same equilibrium temperature. It is crucial to note that the constituents of any substance exhibit increased disorder at higher temperatures. As a cold substance absorbs heat, its constituents become more disordered. The energy transfer from a hotter object to a cooler one increases the system's disorder or randomness. This...
Entropy and the Second Law of Thermodynamics
The second law of thermodynamics can be stated quantitatively using the concept of entropy. Entropy is the measure of disorder of the system.
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
Second Law of Thermodynamics
In the quest to identify a property that may reliably predict the spontaneity of a process, a promising candidate has been identified: entropy. Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, a significant conclusion regarding the relation between this property and spontaneity may be reached. In thermodynamic models, the...

