Periodic Reporting for period 1 - SingletSQL (Nuclear singlet state in diamond for overcoming the standard quantum limit in gravitational wave detectors)
Reporting period: 2023-01-15 to 2025-01-14
O2: Squeezing optimization on an optomechanical system is not complete without studying entanglement issues between the parts of the system. Working in this direction, I studied entanglement between optics and mechanics when it is parametrically driven and how the squeezing is being manipulated based on entanglement [2].
O3: I investigated the entanglement and non-locality between specific spectral components of continuous variable two-mode squeezed mixed states, identifying their limits [3,4]. These spectral components are selected from output modes using filters commonly employed in optomechanical systems. I have chosen two different types of filters and determined both thermalization dynamics and steady-state behaviors of the impact of filters.
efficiency. It suppresses shot noise in the same amount and back action noise more efficiently that acts in lower frequencies (<100 Hz), which is more interesting to the community. In addition, the scheme has also proven to be beneficial for reducing thermal noise by a significant amount. The scheme consists of introducing a double cavity with end mirrors interlocked by a pivot and moving in opposite directions.
WP2: I show how to squeeze mechanical motion and entangle the optical field with mechanical motion in an optomechanical system containing a parametric amplification [2]. The scheme is based on optical bistability which emerges in the system for a strong enough driving field. When the steady
state is on the upper branch of the bistable shape, both squeezing and entanglement are greatly enhanced. Regarding the mechanical squeezing, it reaches the standard quantum limit (SQL) in the upper branch of the bistability. Our proposal provides a way to improve quantum effects in optomechanical systems by taking advantage of nonlinearities.
WP3: While studying the impact of filters on the two-mode hybrid squeezing, we consider both the distinct thermalization scenarios, i.e. one occurring in the vacuum state before entering the nonlinear crystal for squeezing and another after the generation of the two-mode squeezed vacuum but before passing through filters and detectors [3,4]. Both entanglement and nonlocality reach their peak when the filters are identical. However, increasing the degree of input squeezing while applying non-identical filters disrupts both entanglement and non-locality, leading to a bell-shaped pattern. Additionally, I provided precise boundaries for entanglement and non-locality. Combined with the filter, the population of two-mode squeezed thermal light influences the angle of a maximally squeezed hybrid quadrature.