Non-signalling boxes (NS) are theoretical resources defined by the principle of no-faster-than-light communication. They generalize quantum correlations (Q), and some of them are known to collapse communication complexity (CC). However, this collapse is strongly believed to be unachievable in Nature, so its study leads to a better understanding of Q. In the present letter, we find a better sufficient condition for a nonlocal box to collapse CC, thus extending the known collapsing region. In some slices of NS, we show this condition coincides with an area outside of an ellipse.

翻译：非信号盒子（NS）是由“不能超光速通信”原则定义的理论资源。它们推广了量子关联（Q），其中部分已知会坍塌通信复杂度（CC）。然而，这种坍塌被强烈认为在自然界中无法实现，因此对其研究有助于更深入地理解Q。在本报告中，我们找到了一个更好的充分条件，使得非局域盒子坍塌CC，从而扩展了已知的坍塌区域。在NS的某些切片中，我们证明该条件与椭圆外的区域一致。