The signal of a stochastic gravitational wave (GW) background has been sought for several decades and has just come within the observational reach through the pulsar timing array. While several sources of GW background have been analysed in the literature, the phenomenon of scalar-induced GW emerges as a simple and inevitable candidate. Scalar-induced GW are highly sensitive to primordial non-Gaussianity, such as three-point and four-point correlations of primordial scalar perturbations. In this talk, I shall discuss the unique signature of chirality imparted to scalar-induced GW by the parity-odd component of the four-point correlation, the trispectrum. The degree of chirality in GW allows us to impose an independent limit on the strength of the parity-odd trispectrum and compare against observational bounds. Our results motivate the treatment of chirality of GW and parity-odd trispectrum as complementary predictions of parity-violating theories. They further supplement our knowledge of primordial non-Gaussianity elicited from CMB and galaxy surveys.

Synopsis talk

In this talk, I will discuss the thermalization phenomena in closed as well as open quantum systems. Starting with the discussion of thermalization in non-integrable closed quantum systems, i.e., the eigenstate thermalization hypothesis (ETH), I will highlight the critical role entanglement plays in achieving it. Afterward, I will shift the discussion to open quantum systems (OQS), as environmental influence is ubiquitous. In the OQS paradigm, I will discuss about our study on thermalization through a more general process, called Quantum Homogenization. I will demonstrate how memory effects (non-Markovianity) of the dynamics affect thermalization, and present a qualitative comparison of the thermalization process for Markovian and non-Markovian dynamics. Finally, I will shed some light on the process of thermalization via post-Markovian dynamics, which is a generalization of Markovian dynamics incorporating the bath memory effects (hence, basically the ensuing dynamics is non-Markovian in nature). Join Zoom Meeting https://zoom.us/j/98206472628 Meeting ID: 982 0647 2628 Passcode: 560304