[Phys-seminars] 2017-06-08 Lasers Seminar

barmash barmash at bgu.ac.il
Thu Jun 1 13:29:42 IDT 2017


Lasers Seminar

 DATE: 08-06-17

 TIME: 15:30

 PLACE: Physics building (#54) room 207

TITLE: 
A self-interfering clock as a “which path” witness

SPEAKER: 
Yair Margalit, Department of Physics, Ben-Gurion University of the Negev

ABSTRACT/COMMENTS: 
In Einstein\'s general theory of relativity, time depends locally on gravity; in standard quantum theory, time is global—all clocks “tick” uniformly. In the talk I will describe a new tool for investigating time in the overlap of these two theories: a self-interfering clock, comprising two atomic spin states. We prepare the clock in a spatial superposition of quantum wave packets, which evolve coherently along two paths into a stable interference pattern. If we make the clock wave packets “tick” at different rates, to simulate a gravitational time lag, the clock time along each path yields “which path” information, degrading the pattern\'s visibility. In contrast, in standard interferometry, time cannot yield “which path” information. This proof-of-principle experiment may have implications for the study of time and general relativity and their impact on fundamental effects such as decoherence and the emergence of a classical world.


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