1.1k citations · 3.1k across the 54 of their papers we have counts for
54 papers
Bi-scalar-tensor theory: a spatially covariant gravity approach
Jia-Jun Chen, Xian Gao, Tsutomu Kobayashi
We propose a novel method for constructing ghost-free multi-field higher-derivative scalar-tensor theories. The idea is to start from spatially covariant gravity and couple it to a…
Scalar induced gravitational waves in symmetric teleparallel gravity with a parity-violating term
Fengge Zhang, Jia-Xi Feng, Xian Gao
Gravitational waves (GWs) are useful to test gravitational theories and to probe the physics in the early universe. In this paper, we investigate the scalar induced gravitational w…
Minimally modified gravity with auxiliary constraints formalism
Zhi-Bang Yao, Michele Oliosi, Xian Gao +1
We investigate the possibility of reducing the number of degrees of freedom (d.o.f.) starting from generic metric theories of gravity by introducing multiple auxiliary constraints…
Scalar induced gravitational waves from Chern-Simons gravity during inflation era
Jia-Xi Feng, Fengge Zhang, Xian Gao
We investigate the scalar induced gravitational waves (SIGWs) in the Chern-Simons (CS) gravity with a dynamical scalar field during slow roll inflation. Due to the parity violation…
Cosmological perturbations in the spatially covariant gravity with a dynamical lapse function
Xue-Zheng Zhu, Yang Yu, Xian Gao
We investigate the scalar perturbations in a class of spatially covariant gravity theory with a dynamical lapse function. Generally, there are two scalar degrees of freedom due to…
Circularly polarized scalar induced gravitational waves from the Chern-Simons modified gravity
Fengge Zhang, Jia-Xi Feng, Xian Gao
We investigate the scalar induced gravitational waves (SIGWs) in the Chern-Simons (CS) modified gravity during the radiation dominated era. The SIGWs are circularly polarized, whic…