Subhashish Barik, Dhiman Kumar Kalita, Bikash K. Behera, Prasanta K. Panigrahi

Quantum Zeno Effect (QZE) has been one of the most interesting phenomena in quantum mechanics ever since its discovery in 1977 by Misra and Sudarshan [J. Math. Phys. \textbf{18}, 756 (1977)]. There have been many attempts for experimental realization of the same. Here, we present the first ever simulation of QZE on IBM quantum experience platform. We simulate a two-level system for Rabi-driven oscillation and then disturb the time evolution by intermediate repetitive measurements using quantum gates to increase the survival probability of the qubit in the initial state. The circuits are designed along with the added intermediate measurements and executed on IBM quantum simulator, and the outcomes are shown to be consistent with the predictions. The increasing survival probability with the number of intermediate measurements demonstrates QZE. Furthermore, some alternative explanations for the obtained results are provided which leads to some ambiguity in giving the exact reasoning for the observed outcomes.

Aniket Agrawal, Teppei Okumura, Toshifumi Futamase

We show that future observations of binary neutron star systems with electromagnetic counterparts together with the traditional probes of low- and high-redshift type IA supernovae can help resolve the Hubble tension. The luminosity distance inferred from these probes and its scatter depend on the underlying cosmology. By using the gravitatonal lensing of light or gravitational waves emitted by, and peculiar motion of, these systems we derive constraints on the sum of neutrino masses, the equation of state of dark energy parametrised in the form $w_0 + w_a (1-a)$, along with the Hubble constant and cold dark matter density in the Universe. We show that even after marginalising over poorly constrained physical quantities, such as the sum of neutrino masses and the nature of dark energy, low-redshift gravitational wave observations, in combination with type IA supernovae, have the potential to rule out new physics as the underlying cause of the Hubble tension at $\gtrsim 4$-$\sigma$.