量子气体中波动的普遍状态方程
Lena H Dogra1, Gevorg Martirosyan2, Timon A Hilker2,3
1Cavendish Laboratory, University of Cambridge, Cambridge, UK. lhb31@cam.ac.uk.
Nature
|July 26, 2023
概括
研究人员开发了一种状态方程,用于超冷原子斯气体中的动荡物质波. 这个方程描述了一个普遍的,非平衡状态,提供了超越经典热力学流的新见解.
科学领域:
- 热力学
- 量子气体
- 流体动力学
背景情况:
- 状态方程 (EoS) 在平衡热力学中是基本的.
- 将这些概念扩展到远离平衡的系统仍然是一个重大挑战.
- 流是非平衡热力学的一个关键领域.
研究的目的:
- 通过实验构建一个流物质波的状态方程.
- 在同质的超冷原子斯气体中描述非热,静态状态.
- 为流系统建立通用热力学关系.
主要方法:
- 使用同质的超冷原子斯气体.
- 在长度尺度上应用连续强迫,在小尺度上消散.
- 分析了功率定律的动量分布和规模不变的能量流.
主要成果:
- 确立了物质波流的状态方程.
- 确定了动量分布幅度和能量流量作为平衡状态变量.
- 通过各种相互作用强度和密度来证明EoS的经验性扩展,从而产生一种无维的普遍EoS.
结论:
- 由此衍生出的通用状态方程是独立于能量注入/消散细节和系统历史的.
- 这项工作为流系统理论提供了基准.
- 这些发现可能与超冷气体以外的各种流系统有关.
相关概念视频
Ideal Gas Equation
6.9K
The ideal gas equation is an equation of state that relates the state variables pressure, volume, temperature, and the number of moles of a hypothetical gas. This equation is a combination of four empirical laws, namely Boyle’s Law, Charles’s Law, Avogadro’s Law, and Gay-Lussac’s Law. When the proportionalities of the above four empirical laws are combined, it results in a single proportionality constant known as the universal gas constant.
6.9K
Van der Waals Equation
4.2K
The ideal gas law is an approximation that works well at high temperatures and low pressures. The van der Waals equation of state (named after the Dutch physicist Johannes van der Waals, 1837−1923) improves it by considering two factors.
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
4.2K
Entropy
30.4K
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...
30.4K
The Quantum-Mechanical Model of an Atom
42.5K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
42.5K
Energy Conservation and Bernoulli's Equation
9.0K
Applying the conservation of energy principle or the work-energy theorem to an incompressible, inviscid fluid in laminar, steady, irrotational flow leads to Bernoulli's equation. It states that the sum of the fluid pressure, potential, and kinetic energy per unit volume is constant along a streamline.
All the terms in the equation have the dimension of energy per unit volume. The kinetic energy per unit volume is called the kinetic energy density, and the potential energy per unit volume is...
All the terms in the equation have the dimension of energy per unit volume. The kinetic energy per unit volume is called the kinetic energy density, and the potential energy per unit volume is...
9.0K
Equation of State
1.8K
The equation of state is an equation that relates physical quantities, such as pressure, volume, temperature, and the number of moles, of a thermodynamics system with each other. The equation relating physical quantities with each other can be a simple mathematical expression or too complicated to express in mathematical form. In either case, a relationship between physical quantities exists. If the equation of state cannot be expressed in a mathematical form, then experimental data and...
1.8K


