Program

SESSION 2: Loophole-free Bell test 2 (Pavilion I - III)

Chair: Michael Raymer (Oregon)
10:30 am - 11:00 amMarissa Giustina, Zeilinger group (Vienna)
A significant-loophole-free test of Bell's theorem with entangled photons

Abstract. Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell's inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. Here we report a Bell test that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance.

11:00 am - 11:30 amLynden K. Shalm, Nam group (NIST, Boulder)
A strong loophole-free test of local realism

Abstract. Quantum mechanics is a statistical theory. It cannot with certainty predict the outcome of all single events, but instead it predicts probabilities of outcomes. This probabilistic nature of quantum theory is at odds with the determinism inherent in Newtonian physics and relativity, where outcomes can be exactly predicted given sufficient knowledge of a system. In 1935, Einstein, Podolsky, and Rosen wrote “While we have thus shown that the wave function does not provide a complete description of the physical reality, we left open the question of whether or not such a description exists. We believe, however, that such a theory is possible.” It was hoped that quantum theory could be augmented with extra “hidden” variables that determine the outcomes of all possible measurements (a principle known as realism). In 1964, John Bell showed that for such a theory to agree with the predictions of quantum mechanics, hidden variables in one location can instantly change values because of events happening in distant locations. This seemingly violates the locality principle from relativity, which says that objects cannot signal one another faster than the speed of light. Using Bell’s theorem it is possible to test whether reality is governed by local realism. In this talk I will discuss our work at NIST testing Bell’s inequalities relying only on a minimal set of assumptions. We have developed a high-quality source of entangled photons, high-efficiency single-photon detectors, and fast random number generators that are space-like separated from one another. Our experiment closes and addresses all of the major loopholes that are known to exist in Bell tests. This Bell test machine we are building will be used to certify randomness that is useful in a number of cryptographic and security protocols.

11:30 am - 12:00 pmScott Glancy, (NIST, Boulder)
Data analysis for "A strong loophole-free test of local realism"

Abstract. Recent loophole-free tests of local realism have incorporated new analysis techniques to compute p-values (measures of statistical significance of the experiments). The new techniques do not require the support of assumptions upon which old techniques rely, they are effective for small data sets, and they accommodate imperfections in random number generators used to make measurement choices. In this talk I will describe the data analysis techniques used in the test of local realism performed at NIST. I will review the theory used to compute p-values, explain how it was implemented on our experiment's data, and compare our techniques to those used in the tests of local realism performed in Delft and Vienna.

SQuInT Chief Organizer
Prof. Akimasa Miyake
amiyake@unm.edu

SQuInT Co-Organizer
Prof. Elohim Becerra
fbecerra@unm.edu

SQuInT Founder
Prof. Ivan Deutsch
ideutsch@unm.edu

SQuInT Administrator
Gloria Cordova
gjcordo1@unm.edu
505 277-1850

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