空间曲率是否在FLRW表观视界处产生新的热力学临界性？
Does spatial curvature generate new thermodynamic criticality at the FLRW apparent horizon?
- Pontificia Universidad Católica de Valparaíso（智利天主教瓦帕拉索大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究将表观视界热力学推广到含非零空间曲率的FLRW宇宙，发现空间曲率会重新标度临界量但不产生新普适类，还推导了二次全息模型的共存曲线并指出轨迹相交是独立动力学问题。
AI中文摘要：
我们将文献[1]的表观视界热力学构造推广到具有非零空间曲率、非相互作用冷暗物质和全息型暗能量的FLRW宇宙中。对于非零曲率，标度因子是视界状态方程中的额外几何变量，因此在给出曲率部分的闭合方案之前，常规的临界性条件无法良好定义。我们引入一个无量纲曲率变量，并将热力学变化限制在该变量取常数值的切片上。对于每个此类切片，正的全息耦合和大于1的非线性幂次保证了唯一正临界点的存在。临界比体积、温度和压力会因空间曲率而发生偏移，而临界比和平均场临界指数保持不变，因此空间曲率会重新标度临界量，但不会产生新的局域普适类。我们从物理热力学体积和与重新标度的视界温度共轭的熵出发，构造了亥姆霍兹势。在二次全息模型中，等价于麦克斯韦构造的参数共存曲线由竞争分支的吉布斯自由能相等性导出。相关的潜热在临界端点处消失，导致固定曲率系综中存在全局一阶共存。由于无量纲曲率变量在宇宙膨胀过程中通常会演化，物理的FLRW轨迹是否会与临界或共存轨迹相交是一个独立的动力学问题。
英文摘要：
We generalize the apparent-horizon thermodynamic construction of [1] to a FLRW universe with non-zero spatial curvature, non-interacting cold dark matter and holographic-type dark energy. For nonzero curvature, the scale factor is an additional geometric variable in the horizon equation of state. The usual criticality conditions are thus not well defined until a closure prescription for the curvature sector is provided. We introduce a dimensionless curvature variable and restrict the thermodynamic variations to slices of constant value of this variable. For each such slice, a positive holographic coupling and nonlinear powers larger than one guaranty the existence of a unique positive critical point. The critical specific volume, temperature and pressure are shifted by the spatial curvature, while the critical ratio and the mean-field critical exponents remain unchanged. It thus rescales the critical quantities, without generating a new local universality class. We construct a Helmholtz potential out of the physical thermodynamic volume and the entropy conjugate to the rescaled horizon temperature. In the quadratic holographic model, the parametric coexistence curve which is equivalent to the Maxwell construction is derived from the equality of the Gibbs free energies of the competing branches. The associated latent heat disappears at the critical endpoint, resulting in a global first-order coexistence in the fixed-curvature ensemble. Whether a physical FLRW trajectory intersects the critical or coexistence locus is a separate dynamical question because the dimensionless curvature variable generally evolves during cosmological expansion.
