ABSTRACT
Parity violation in the early universe holds great promise for uncovering new physics. In particular, the primordial scalar four-point correlation function is allowed to develop a parity-violating component when massive spinning particles coupled to a helical chemical potential. In the first part of talk, the speaker will present when inflaton has a reduced sound speed, the dynamics admits an effective non-local description which yields a compact parity-odd trispectrum template in terms of elementary functions. For general case which allows for the exchange of additional states of any mass and integer spin, he will introduce a decomposition of the inflationary bulk-bulk propagator of massive spinning fields which ensures the time-ordered contributions are purely real after rotating to Euclidean time. Building on this decomposition, he will demonstrate that the parity-odd correlators are always factorized at the tree-level under the assumption of scale invariance.
BIOGRAPHY
Dr. Yuhang Zhu is currently a postdoctoral researcher at the Institute of Basic Science in Korea. He obtained his PhD in 2023 from the Hong Kong university of science and technology. He works on theoretical cosmology and his recent research interests include cosmological correlators, gravitational waves, and probing new physics in the early universe.
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