Ultraviolet regularity from quantum gravitational indefinite causal structure

Reduction of correlations by quantum indefinite causal structure

We show that quantum indefinite causal structure generically reduce two-party correlations. For significant indefiniteness in the causal structure captured by some general conditions, the correlation is shown to be reduced down to zero. The result offers an operational model-independent ultraviolet regularization mechanism. It may be applied to various approaches of quantum gravity that allow quantum indefinite spacetime causal structure.

Unitarity and ultraviolet regularity in cosmology

Quantum field theory in curved space-times is a well developed area in mathematical physics which has had important phenomenological applications to the very early universe. However, it is not commonly appreciated that on time dependent space-times ---including the simplest cosmological models--- dynamics of quantum fields is not unitary in the standard sense. This issue is first explained with an explicit example and it is then shown that a generalized notion of unitarity does hold. The generalized notion allows one to correctly pass to the Schrödinger picture starting from the Heisenberg pic…

mLQC-I混合方法中的高精度半解析模式函数、紫外正则性与粒子产生

High-Accuracy Semi-Analytic Mode Functions, Ultraviolet Regularity, and Particle Creation in the Hybrid Approach to mLQC-I

本研究在mLQC-I混合方法中构造高精度半解析模式函数，证实有限模式粒子产生与紫外正则性共存，为原初功率谱计算提供基础，相关紫外结论可推广至dressed-metric方法。

来自高导数有效 delta 源的正则黑洞

Regular black holes from higher-derivative effective delta sources

本章研究高导数引力中的有效 delta 源，通过一般模型与牛顿极限分析源的紫外正则性，并据定理构造曲率及其协变导数不变量均正则的黑洞度规。

在无奇点理论中，拓扑不变量（和黑洞）会发生什么？

What happens to topological invariants (and black holes) in singularity-free theories?

本文研究无奇点势对拓扑不变量的影响，发现线性理论中正则性破坏拓扑不变量并产生可观测的半径依赖Aharonov–Bohm相位，而广义相对论中Reissner–Nordström黑洞切除核心区域后仍保持电磁拓扑不变量，但高阶曲率不变量仍有奇点，提示需考虑修正引力理论。