Quantum entanglement, a phenomenon where different parts of a system display correlations that cannot be explained using non-quantum means, has long been a challenge to harness for practical applications. The inevitable leakage of energy and information from a quantum system into its surrounding environment, known as dissipation, is typically a source of errors. However, researchers have now demonstrated that dissipation can be engineered to generate and maintain steady-state entanglement between superconducting qubits, offering a more robust and reliable alternative to current methods of entanglement generation.
The collaboration between physicists at the University of Illinois Urbana-Champaign and the University of Chicago has realized a theoretical prediction in which an externally driven quantum system achieves entanglement through dissipation. The team developed a technique called synthetic squeezing that accounts for real-world noise and hardware imperfections, allowing high-quality entanglement without physically transporting qubits in delicate quantum states.
This research, published in the journal Physical Review X, introduces a new approach to entanglement generation. Instead of preparing entanglement at one location and then transporting it to another, the team has shown that it's possible to bypass the transport stage altogether. This is achieved by continuously absorbing and emitting light, with some of this light dissipated into the surrounding environment. By carefully engineering this steady state, the researchers can result in the atoms or qubits displaying entanglement.
The generated entanglement is in a steady state, meaning it can be maintained indefinitely over arbitrarily large distances. This is a significant advancement, as current methods of distributing entanglement often experience decoherence during transit, leading to the erosion of entanglement. The researchers believe that this technique holds promise for quantum networking, entanglement distillation, and distributed quantum computing.
What makes this particularly fascinating is the idea of a 'refrigerator' that pumps out external influences to maintain entanglement instead of pumping out heat to maintain coldness. This challenges our traditional understanding of quantum entanglement, where it is typically prepared and then watched as it decays. The researchers have shown that entanglement can emerge as the natural point of relaxation in a system, even in the presence of noise and hardware imperfections.
The next steps for the research team include extending the process to multi-qubit systems and exploring the implementation of different protocols. The potential for entanglement distillation, where a collection of qubits with low entanglement can be combined to achieve a few with very high entanglement, is particularly exciting. This could enable the realization of actual quantum computing operations with the system.
In summary, this research demonstrates a novel approach to entanglement generation, offering a more robust and reliable method for quantum information processing. By harnessing dissipation, the team has overcome a significant barrier to the practical realization of quantum technology, opening up new possibilities for the future of quantum computing and communication.
