Squeezing restored by 7.6% with a new quantum smoothing method

Researchers have restored quantum squeezing by 7.6% ± 2.6% using a new quantum smoothing method, exceeding improvements seen in standard state purification techniques. The experiment split the output of an optical parametric oscillator, creating ‘observed’ and ‘unobserved’ channels to model how lost quantum information impacts system coherence. This approach allowed the team to demonstrate a 10.3% ± 1.6% improvement in state purification, combating decoherence, a major challenge for realizing practical quantum information technologies, by using both past and future measurement data. A 7.6% ± 2.6% restoration of quantum squeezing was achieved through a novel quantum smoothing method, exceeding gains observed through state purification alone. The technique, demonstrated using an optical parametric oscillator, addresses a fundamental challenge in quantum information science: recovering coherence lost to environmental decoherence. Unlike conventional filtering, this smoothing approach…