超流体宇宙
The Superfluid Universe
摘要：
我们讨论量子真空的现象学。宏观系统的唯象学有三个来源：热力学、拓扑学和对称性。自持真空的热力学允许我们处理与真空能量有关的问题：宇宙学常数问题。自维持真空的平衡态的能量密度的自然值为零。宇宙学被讨论为真空向平衡态驰豫的过程。与普朗克尺度相比，宇宙学常数的当前值非常小，因为现在的宇宙非常古老，因此接近平衡。动量空间拓扑决定了费米子真空的普适类。标准模型真空在无质量态和有质量态都是拓扑介质。真空在无质量状态下具有超流3 He-A的性质，这是拓扑超流。它属于费米点普适类，它具有拓扑保护的费米准粒子。在低能量下，它们表现为相对论性的无质量外尔费米子。规范场和引力在低能时与外尔费米子一起出现。这使我们能够处理标准模型中的层次问题：与普朗克尺度相比，基本粒子的质量非常小，因为夸克和轻子质量的自然值为零。小的非零质量出现在红外区域，在那里量子真空获得了另一种拓扑超流体3 He-B和3+1拓扑绝缘体的性质。对2+1维和3+1维的其它拓扑介质也进行了讨论。在大多数情况下，拓扑是由底层微观系统的离散对称性支持的，这表明离散对称性在标准模型中的重要作用。
英文摘要：
We discuss phenomenology of quantum vacuum. Phenomenology of macroscopic systems has three sources: thermodynamics, topology and symmetry. Thermodynamics of the self-sustained vacuum allows us to treat the problems related to the vacuum energy: the cosmological constant problems. The natural value of the energy density of the equilibrium the self-sustained vacuum is zero. Cosmology is discussed as the process of relaxation of vacuum towards the equilibrium state. The present value of the cosmological constant is very small compared to the Planck scale, because the present Universe is very old and thus is close to equilibrium. Momentum space topology determines the universality classes of fermionic vacua. The Standard Model vacuum both in its massless and massive states is topological medium. The vacuum in its massless state shares the properties of superfluid 3He-A, which is topological superfluid. It belongs to the Fermi-point universality class, which has topologically protected fermionic quasiparticles. At low energy they behave as relativistic massless Weyl fermions. Gauge fields and gravity emerge together with Weyl fermions at low energy. This allows us to treat the hierarchy problem in Standard Model: the masses of elementary particles are very small compared to the Planck scale because the natural value of the quark and lepton masses is zero. The small nonzero masses appear in the infrared region, where the quantum vacuum acquires the properties of another topological superfluid, 3He-B, and 3+1 topological insulators. The other topological media in dimensions 2+1 and 3+1 are also discussed. In most cases, topology is supported by discrete symmetry of the underlying microscopic system, which indicates the important role of discrete symmetry in Standard Model.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
