The Einstein Equivalence Principle (EEP) underlies general relativity, asserting, from operational viewpoint, that a freely falling laboratory can locally eliminate gravitational effects. But does EEP still hold when the lab is a quantum system—delocalized, entangled, or in a nonclassical spacetime? In such cases, no single classical coordinate choice may exist to render spacetime Minkowskian....
The emergence of quantum mechanics and general relativity has transformed our understanding of the natural world significantly. However, integrating these two theories presents immense challenges, and their interplay remains untested. Recent theoretical studies suggest that single-photon interference over large spatial separations offers a promising approach to probing the interface between...
Is gravity fundamentally quantum, like the other three fundamental interactions, or is it classical? Could gravity play a fundamental role in wave function collapse, as suggested by models such as the Diósi–Penrose (DP) model? These questions remain open.
Many proposed experiments aimed at addressing these questions rely on creating spatial superpositions of large masses. For instance,...
The quest to determine whether gravity is quantum has challenged physicists since the mid-20th century, due to the impracticability of accessing the Planck scale, where potential quantum gravity effects are expected to become relevant. While recent entanglement-based tests have provided a more promising theoretical path forward, the difficulty of preparing and controlling large mass quantum...
Understanding physical phenomena at the intersection of quantum mechanics and general relativity remains one of the major challenges in modern physics. Among various approaches, experimental tests have been proposed to investigate the dynamics of quantum systems in curved spacetime and to examine the quantum nature of gravity in the low-energy regime. However, most previous studies have...
