Post-selected Von Neumann Measurements Enhance Non-Classical Properties of Entangled Coherent States

Entangled coherent states represent a powerful resource for quantum technologies, but maintaining and enhancing their non-classical properties remains a significant challenge. Janarbek Yuanbek from the Institute of Semiconductors, Chinese Academy of Sciences, and Bruno Tenorio from Wolfram Research South America, investigate how carefully chosen measurements can amplify these desirable features. Their work demonstrates that post-selected weak measurements, modelled using the von Neumann approach, effectively boost both entanglement and squeezing within these states. The team reveals that tuning the strength of these measurements allows for precise control over the state’s structure, evolving it from simple forms to complex interference patterns, and ultimately improving the precision of phase estimation, paving the way for advanced quantum state engineering.

Weak Measurement Enhances Entangled State Properties

This research systematically investigates how post-selected weak measurements modulate the non-classical properties of entangled coherent states, aiming to achieve controllable enhancement of quantum resources like entanglement and squeezing while minimising disturbance to the quantum state. The team theoretically analyses the post-selected weak measurement process and its effectiveness in amplifying the non-classical features of these states, employing a model that describes the weak-value amplification of the pointer state. Results demonstrate that significant enhancement of squeezing can be achieved by carefully tuning the measurement parameters, allowing for greater control over the quantum state’s properties and offering a pathway towards more efficient manipulation and utilisation of quantum resources in various quantum technologies.

Tunable Entanglement via Weak Measurement Control

Researchers demonstrate a tunable framework for manipulating entangled coherent states through post-selected weak measurements, improving quantum resources like entanglement and squeezing while minimising disturbance to the initial state. Analysis reveals that by adjusting the measurement coupling strength, significant enhancement of squeezing can be achieved, evidenced by changes in the state’s structure in phase space. Furthermore, the team quantified entanglement and observed a pronounced increase with stronger coupling, alongside improved precision in parameter estimation. These results establish a method for precise control over continuous-variable entangled states, offering a pathway for state engineering and quantum information processing.