麻豆淫院

(麻豆淫院Org.com) -- The ability to entangle particles is considered essential for a number of experiments and applications. While we have seen evidence for quantum entanglement, it is still difficult to detect unambiguously. Multiparticle quantum correlations are especially important for work with optical lattices, superconducting qubits and quantum information processing. "Entanglement in large qubit systems is becoming more important," Bastian Jungnitsch tells 麻豆淫院Org.com. "Unfortunately, the characterization of multiparticle entanglement is difficult."

Jungnitsch, a Ph.D. student at the Institute for Quantum Optics and Quantum Information at the Austrian Academy of Sciences in Innsbruck, Austria, has been working on a way to simplify the way that multiparticle entanglement is characterized. Along with Tobias Moroder and Otfried G眉hne from the University of Siegen in Germany, Jungnitsch created criteria that can be easily implemented in experiments. Their work is published in 麻豆淫院ical Review Letters: 鈥淭aming Multiparticle Entanglement.鈥�

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鈥淲e developed a criterion that can easily be implemented so that others can use it,鈥� Jungnitsch says. 鈥淓xperimentalists can download it from the Internet and use it to measure entanglement. It provides results that others can understand, helping to let them know that these particles are really entangled.鈥�

The team from Austria and Germany used what they call 鈥渟uitable relaxations鈥� to develop their criteria. The method involves first considering a quantum state involving three particles. If the state can be separated out using different partitions, it is called biseparable. When in a biseparable state, the system is not considered to be entangled. If, however, the quantum state is not biseparable, it can be thought of as genuinely multiparticle-entangled, meaning that all particles are entangled and not only some of them.

鈥淭here are many states that are entangled in some sense,鈥� Jungnitsch points out, 鈥渂ut it鈥檚 not easy to see if they are genuinely entangled. We relaxed the definition a bit, and it still works pretty well. Our method won鈥檛 work for all entangled states, but you can still catch the phenomena of entanglement pretty well.鈥�

鈥淭he point is to make sure that your particles are in a genuinely entangled state,鈥� Jungnitsch continues. 鈥淚n many cases, you want to know if all of the items prepared are entangled.鈥� Otherwise, for some operations, you might not get the desired results. 鈥淲hen particles are genuinely entangled, they can be useful for a number of operations. Our criteria can help experimentalists verify that the state really is entangled. It鈥檚 something useful and practical.鈥�

Jungnitsch says that they have already provided the code for download. 鈥淚t can be used in experiments now,鈥� he says. 鈥淲e wrote the code and put it on the Internet. Experimentalists can download and then run the code on their own computers as part of their efforts to see whether or not their multiparticle systems are entangled.鈥�

Some refining is still possible, however. 鈥淲e have been working on applying the code to specific states 鈥� important states.鈥� Because there are some applications that require certain quantum states, being able to detect whether or not particles have reached those states is important. With some adjustments to the code, it should be possible to characterize such entangled states even more accurately.

鈥淥f course, the long view is always quantum computers,鈥� Jungnitsch acknowledges. 鈥淏ut there are other applications for quantum correlations as well. The first step to many of these applications, and to improving quantum information processing, is to verify entangled states. Our efforts can help with that.鈥�

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