Hybrid System Generates Non-Gaussian States of Motion in Strong Coupling Regime

Controlling the motion of quantum systems is central to advances in quantum technology, and researchers are now exploring ways to create increasingly complex states of motion. Jugal Talukdar, Scott E. Smart, and Prineha Narang, all from the University of California, Los Angeles, demonstrate the generation and precise control of unusual, non-Gaussian states of motion within a novel hybrid quantum system. Their work focuses on a system where qubits interact with a mechanical resonator that, in turn, couples to a photonic cavity, allowing for versatile control through multiple parameters. The team shows that, by carefully tuning external drives and system interactions, they can create mechanical states exhibiting properties like negative volume in their Wigner distribution, which signifies enhanced sensitivity and potential for applications in precision measurement, metrology, and quantum information processing. This research highlights the tunability of this hybrid platform and opens new avenues for engineering complex quantum states with practical benefits.

Continuous Variable Quantum Information and Optomechanics

This collection of research covers a broad range of topics in quantum optics, optomechanics, and related fields, focusing on encoding and manipulating quantum information using continuous degrees of freedom as an alternative to qubit-based computing. Key concepts explored include squeezed states, cat states, and Gottesman-Kitaev-Preskill (GKP) states, with optomechanics playing a prominent role in cooling mechanical oscillators and integrating them into quantum information processing systems. Researchers are also investigating hybrid quantum systems, combining superconducting qubits, mechanical oscillators, and spins, as a pathway to more powerful and versatile quantum technologies. A central challenge addressed is quantum transduction, converting quantum information between different physical systems for building large-scale quantum networks. Studies focus on generating and characterizing non-classical states of light and motion, including squeezed and entangled states, utilizing optical cavities to enhance light-matter interactions and achieve strong coupling between light and mechanical motion. The field of quantum metrology, which uses quantum states to improve measurement precision, is also well represented, with ongoing efforts to generate and manipulate these states as fundamental building blocks for many quantum technologies.

Tripartite Hybrid System for State Engineering

Researchers have developed a unique hybrid quantum system, combining qubits, a mechanical resonator, and a cavity, to engineer specific quantum states of motion. This approach moves beyond traditional two-component systems, offering increased control and the potential for complex quantum protocols. The system’s design allows for the manipulation of quantum states not simply as intermediaries for transferring information, but as actively shaped entities within the device itself, centering on strong coupling between all three components to enable significant nonlinear interactions crucial for generating non-Gaussian states. A time-dependent external drive, applied to the cavity, initiates a carefully orchestrated sequence of interactions, effectively “sculpting” the quantum state of the mechanical resonator. By switching off the drive after a specific duration, researchers induce well-defined oscillatory dynamics, allowing for precise control over the system’s evolution. This allows for the creation of highly non-Gaussian states, valuable for certain quantum technologies, with the focus on transient dynamics immediately following the application of the drive, rather than steady-state properties.

Negative Volume States Generated in Hybrid System

Researchers have developed a hybrid quantum system, integrating qubits, a mechanical resonator, and a photonic cavity, capable of generating non-Gaussian states of motion in the mechanical resonator. This achievement represents a significant step towards advanced quantum state engineering and has implications for precision measurement and quantum information processing. The system’s versatility stems from its ability to harness nonlinear interactions and multiple control parameters, allowing for precise manipulation of quantum states, with the team demonstrating the creation of states exhibiting a “negative volume” in the Wigner quasi-probability distribution, indicating non-Gaussian behaviour. These non-Gaussian states offer enhanced sensitivity for certain types of measurements, with the degree of non-Gaussianity being highly tunable. Researchers found that the phase of the qubit component significantly influences the mechanical resonator’s population, while increasing the interaction strength between the resonator and the cavity consistently enhanced the non-Gaussian characteristics. They observed that the system, when initialized with a specific qubit phase, exhibited significantly larger quantum Fisher information compared to a standard coherent state, demonstrating the potential for improved precision in measurement applications.

Hybrid System Generates Tunable Non-Gaussian States

This research demonstrates the generation and control of non-Gaussian states within a hybrid quantum system, comprising qubits coupled to a mechanical resonator and a photonic cavity. By employing a specific time-dependent drive, the team successfully created oscillatory behaviour in the mechanical resonator, resulting in states exhibiting characteristics indicative of quantum behaviour, specifically a negative volume in the Wigner quasi-probability distribution and enhanced Fisher information. These findings highlight the potential of this hybrid platform for advanced quantum state engineering and applications in areas such as precision measurement and information processing. The system begins with initial Gaussian states in both the mechanical and cavity components, and the applied drive protocol effectively manipulates these states to achieve the desired quantum characteristics. The authors acknowledge that their model assumes negligible losses within the system, representing an idealization supported by current experimental capabilities, with future work likely focusing on addressing these limitations and exploring the practical implementation of this approach in more complex quantum systems.