Rutkowski Adam, Buraczewski Adam, Horodecki Paweł, Stobińska Magdalena
Institute of Theoretical Physics and Astrophysics, University of Gdańsk, ulica Wita Stwosza 57, 80-952 Gdańsk, Poland.
National Quantum Information Center of Gdańsk, ulica Władysława Andersa 27, 81-824 Sopot, Poland.
Phys Rev Lett. 2017 Jan 13;118(2):020402. doi: 10.1103/PhysRevLett.118.020402. Epub 2017 Jan 9.
Quantum steering is a relatively simple test for proving that the values of quantum-mechanical measurement outcomes come into being only in the act of measurement. By exploiting quantum correlations, Alice can influence-steer-Bob's physical system in a way that is impossible in classical mechanics, as shown by the violation of steering inequalities. Demonstrating this and similar quantum effects for systems of increasing size, approaching even the classical limit, is a long-standing challenging problem. Here, we prove an experimentally feasible unbounded violation of a steering inequality. We derive its universal form where tolerance for measurement-setting errors is explicitly built in by means of the Deutsch-Maassen-Uffink entropic uncertainty relation. Then, generalizing the mutual unbiasedness, we apply the inequality to the multisinglet and multiparticle bipartite Bell state. However, the method is general and opens the possibility of employing multiparticle bipartite steering for randomness certification and development of quantum technologies, e.g., random access codes.
量子导引是一种相对简单的测试，用于证明量子力学测量结果的值仅在测量行为中才得以产生。通过利用量子关联，爱丽丝可以以一种在经典力学中不可能的方式影响（导引）鲍勃的物理系统，这表现为对导引不等式的违背。对于尺寸不断增加甚至接近经典极限的系统，证明这种以及类似的量子效应是一个长期存在的具有挑战性的问题。在此，我们证明了一个在实验上可行的对导引不等式的无界违背。我们推导了其通用形式，其中通过多伊奇 - 马森 - 乌芬克熵不确定关系明确地纳入了对测量设置误差的容忍度。然后，推广相互无偏性，我们将该不等式应用于多单态和多粒子二分贝尔态。然而，该方法具有通用性，并为利用多粒子二分导引进行随机性认证和量子技术（例如随机访问码）的发展开辟了可能性。
