2015/05/21 by Yair Margalit, Zhifan Zhou, Shimon Machluf +3 · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1126/science.aac6498
22 pages, 8 figures
arxiv created 2015/05/21 · arxiv updated 2015/10/28
We experimentally demonstrate a new interferometry paradigm: a self-interfering clock. We split a clock into two spatially separated wave packets, and observe an interference pattern with a stable phase showing that the splitting was coherent, i.e., the clock was in two places simultaneously. We then make the clock wave packets "tick" at different rates to simulate a proper time lag. The entanglement between the clock's time and its path yields "which path" information, which affects the visibility of the clock's self-interference. By contrast, in standard interferometry, time cannot yield "which path" information. As a clock we use an atom prepared in a superposition of two spin states. This first proof-of-principle experiment may have far-reaching implications for the study of time and general relativity and their impact on fundamental quantum effects such as decoherence and wave packet collapse.