For the first time, Princeton physicists have achieved a groundbreaking feat by entangling individual molecules, allowing them to remain correlated and interact even when separated by vast distances. Recently published in Science, this research marks a significant breakthrough in the world of molecules, primarily due to the fundamental importance of quantum entanglement, according to Lawrence Cheuk, the senior author and assistant professor of physics at Princeton University.
Quantum entanglement is not only a theoretical marvel but also holds promise for practical applications. Entangled molecules can serve as building blocks for various applications, including quantum computers that can outpace conventional ones, quantum simulators for modeling complex materials, and quantum sensors with faster measurement capabilities.
Connor Holland, a co-author and graduate student in the physics department, underscores the motivation behind quantum science: harnessing the laws of quantum mechanics to achieve superior performance in diverse areas. The core principles driving quantum advantage are superposition and quantum entanglement, distinguishing quantum bits (qubits) from classical computer bits.
Entanglement, a cornerstone of quantum mechanics, refers to particles being inextricably linked, maintaining this connection even across vast distances. Initially dubbed “spooky action at a distance” by Einstein, entanglement has been validated by physicists, emphasizing its accurate representation of reality.
Despite the potential of quantum technologies, the challenge lies in determining the optimal physical platform for creating qubits. Various technologies, including trapped ions, photons, and superconducting circuits, have been explored, with the choice depending on specific applications.
Until this experiment, molecules posed challenges for achieving controllable quantum entanglement. Cheuk and colleagues overcame these hurdles by carefully manipulating individual molecules in the laboratory, coaxing them into interlocking quantum states.
Molecules, chosen for their unique advantages over atoms, present new opportunities for quantum information processing and simulating complex materials. Molecules offer more quantum degrees of freedom and interaction possibilities compared to atoms.
Yukai Lu, a co-author and graduate student in electrical and computer engineering, highlights the practical implications, explaining how molecules, with multiple vibrational and rotational modes, offer new ways of storing and processing quantum information. Even when spatially separated, polar molecules can interact.
Controlling molecules in the laboratory, however, has been challenging due to their complexity. The Princeton team addressed these challenges through a meticulously designed experiment involving laser-cooling molecules to ultracold temperatures and using optical tweezers to manipulate individual molecules.
By encoding qubits into molecular states and using microwave pulses to induce coherent interactions, the researchers successfully entangled individual molecules. This achievement, a two-qubit gate, is crucial for universal digital quantum computing and simulating complex materials.
The research opens avenues for investigating quantum science, particularly in simulating many interacting molecules to explore emergent behaviors. Cheuk emphasizes the novelty of using molecules for quantum science and the demonstrated on-demand entanglement as a crucial step toward establishing molecules as a viable platform for quantum science.
In a separate article in the same issue of Science, an independent research group at Harvard University and MIT, led by John Doyle, Kang-Kuen Ni, and Wolfgang Ketterle, achieved similar results. This convergence underscores the reliability of the findings and emphasizes the growing excitement around molecular tweezer arrays as a promising new platform for quantum science.
Source: Princeton University