麻豆淫院

(麻豆淫院Org.com) -- Few people doubt the "quantumness" of entanglement. Quantifying the quantum correlation of entanglement is something that is relatively regular right now. However, things change a bit when it comes to quantum correlations other than entanglement. However, there is a growing interest in the use of non-entanglement quantum correlations in a number of possible future applications.

鈥淎 few years ago, scientists proposed quantum discord as a quantum correlation measure that goes beyond the entanglement paradigm,鈥� Roberto Serra tells 麻豆淫院Org.com. 鈥淨uantum discord may be present, even in separate, non-entangled states. However, some doubt was being shed on the quantum qualities of non-entangled states because of the difficulty in quantifying the correlations.鈥�

In order to remedy the difficulty in 鈥渟eeing鈥� the correlations in a laboratory setting, Serra, a scientist at the Federal University of ABC in S茫o Paulo, Brazil, worked with a group to create a technique that makes it possible to recognize nonclassical correlations in quantum discord. Serra worked with a team from different Brazilian institutions of higher learning, including the Brazilian Agricultural Research Corporation's and the Brazilian Center for 麻豆淫院ics Research both in Rio de Janeiro, and the 麻豆淫院ics Institute of S茫o Carlos, in S茫o Paulo State. The results of the work can be seen in 麻豆淫院ical Review Letters: Experimentally Witnessing the Quantumness of Correlations.鈥�

鈥淣uclear Magnetic Resonance systems at room temperature were used to test principles of quantum computation with a good level of success,鈥� Serra explains. 鈥淭he quantum nature of these demonstrations was questioned because there is no entanglement in such a system. In our experiment we reveled directly the quantum nature of this system at room temperature. We used a sample of chloroform molecules, since it鈥檚 the simplest two-qubit system. We folded a qubit in the carbon nucleus and another one in the hydrogen nucleus.鈥�

Next the Brazilian scientists were able to manipulate the system. Even though they used hot quantum bits, the system actually works as a quantum mechanical one. 鈥淲e displaced the system from the thermal equilibrium by a very tiny deviation, and the phase coherence present there could encode quantum correlations as the measured by the quantum discord,鈥� Serra says.

鈥淥ur methods can be applied to another system, such as an optical system. This can enable us to say if a given system is purely classical in nature, or if it has truly quantum correlations,鈥� he continues. Serra thinks that using this test, which is relatively simple to perform in a laboratory setting, could help lay to rest the debate over whether or not these other types of correlations are truly quantum.

鈥淲e test the quantumness of discord at room temperature, and this very robust quantumness can be used to get an advantage in quantum protocols,鈥� Serra insists. He believes that this method can already be used for metrology. 鈥淲e are involved now in a test of principles in quantum metrology using this type of system, and exploiting this very tiny nonclassical correlation. We are testing those right now, to see about advantages over classical protocols, and we hope to have new results in the next few months.鈥�

鈥淲e hope to develop future applications, and advance our comprehension about the rule played by this kind of quantumness in tasks as, for example, quantum communications,鈥� Serra continues. 鈥淲e are building collaborations between theoretical and experimental researchers, and we hope that we can do more to show the usefulness of other quantum correlations beyond entanglement.鈥�

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