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Title: Cosmic Bell Test: Measurement Settings from Milky Way Stars

Abstract

Bell’s theorem states that some predictions of quantum mechanics cannot be reproduced by a local-realist theory. That conflict is expressed by Bell’s inequality, which is usually derived under the assumption that there are no statistical correlations between the choices of measurement settings and anything else that can causally affect the measurement outcomes. In previous experiments, this “freedom of choice” was addressed by ensuring that selection of measurement settings via conventional “quantum random number generators” was spacelike separated from the entangled particle creation. This, however, left open the possibility that an unknown cause affected both the setting choices and measurement outcomes as recently as mere microseconds before each experimental trial. Here in this paper we report on a new experimental test of Bell’s inequality that, for the first time, uses distant astronomical sources as “cosmic setting generators.” In our tests with polarization-entangled photons, measurement settings were chosen using real-time observations of Milky Way stars while simultaneously ensuring locality. Assuming fair sampling for all detected photons, and that each stellar photon’s color was set at emission, we observe statistically significant ≳7.31σ and ≳11.93σ violations of Bell’s inequality with estimated p values of ≲1.8 × 10 -13 and ≲4.0 × 10 -33, respectively,more » thereby pushing back by ~600 years the most recent time by which any local-realist influences could have engineered the observed Bell violation.« less

Authors:
 [1]; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
  1. Austrian Academy of Sciences, Vienna, Austria
Publication Date:
Research Org.:
Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
Sponsoring Org.:
USDOE
OSTI Identifier:
1342816
Alternate Identifier(s):
OSTI ID: 1425643
Grant/Contract Number:
SC0012567
Resource Type:
Journal Article: Published Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 6; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Citation Formats

Handsteiner, Johannes, Friedman, Andrew S., Rauch, Dominik, Gallicchio, Jason, Liu, Bo, Hosp, Hannes, Kofler, Johannes, Bricher, David, Fink, Matthias, Leung, Calvin, Mark, Anthony, Nguyen, Hien T., Sanders, Isabella, Steinlechner, Fabian, Ursin, Rupert, Wengerowsky, Sören, Guth, Alan H., Kaiser, David I., Scheidl, Thomas, and Zeilinger, Anton. Cosmic Bell Test: Measurement Settings from Milky Way Stars. United States: N. p., 2017. Web. doi:10.1103/PhysRevLett.118.060401.
Handsteiner, Johannes, Friedman, Andrew S., Rauch, Dominik, Gallicchio, Jason, Liu, Bo, Hosp, Hannes, Kofler, Johannes, Bricher, David, Fink, Matthias, Leung, Calvin, Mark, Anthony, Nguyen, Hien T., Sanders, Isabella, Steinlechner, Fabian, Ursin, Rupert, Wengerowsky, Sören, Guth, Alan H., Kaiser, David I., Scheidl, Thomas, & Zeilinger, Anton. Cosmic Bell Test: Measurement Settings from Milky Way Stars. United States. doi:10.1103/PhysRevLett.118.060401.
Handsteiner, Johannes, Friedman, Andrew S., Rauch, Dominik, Gallicchio, Jason, Liu, Bo, Hosp, Hannes, Kofler, Johannes, Bricher, David, Fink, Matthias, Leung, Calvin, Mark, Anthony, Nguyen, Hien T., Sanders, Isabella, Steinlechner, Fabian, Ursin, Rupert, Wengerowsky, Sören, Guth, Alan H., Kaiser, David I., Scheidl, Thomas, and Zeilinger, Anton. Tue . "Cosmic Bell Test: Measurement Settings from Milky Way Stars". United States. doi:10.1103/PhysRevLett.118.060401.
@article{osti_1342816,
title = {Cosmic Bell Test: Measurement Settings from Milky Way Stars},
author = {Handsteiner, Johannes and Friedman, Andrew S. and Rauch, Dominik and Gallicchio, Jason and Liu, Bo and Hosp, Hannes and Kofler, Johannes and Bricher, David and Fink, Matthias and Leung, Calvin and Mark, Anthony and Nguyen, Hien T. and Sanders, Isabella and Steinlechner, Fabian and Ursin, Rupert and Wengerowsky, Sören and Guth, Alan H. and Kaiser, David I. and Scheidl, Thomas and Zeilinger, Anton},
abstractNote = {Bell’s theorem states that some predictions of quantum mechanics cannot be reproduced by a local-realist theory. That conflict is expressed by Bell’s inequality, which is usually derived under the assumption that there are no statistical correlations between the choices of measurement settings and anything else that can causally affect the measurement outcomes. In previous experiments, this “freedom of choice” was addressed by ensuring that selection of measurement settings via conventional “quantum random number generators” was spacelike separated from the entangled particle creation. This, however, left open the possibility that an unknown cause affected both the setting choices and measurement outcomes as recently as mere microseconds before each experimental trial. Here in this paper we report on a new experimental test of Bell’s inequality that, for the first time, uses distant astronomical sources as “cosmic setting generators.” In our tests with polarization-entangled photons, measurement settings were chosen using real-time observations of Milky Way stars while simultaneously ensuring locality. Assuming fair sampling for all detected photons, and that each stellar photon’s color was set at emission, we observe statistically significant ≳7.31σ and ≳11.93σ violations of Bell’s inequality with estimated p values of ≲1.8 × 10-13 and ≲4.0 × 10-33, respectively, thereby pushing back by ~600 years the most recent time by which any local-realist influences could have engineered the observed Bell violation.},
doi = {10.1103/PhysRevLett.118.060401},
journal = {Physical Review Letters},
number = 6,
volume = 118,
place = {United States},
year = {Tue Feb 07 00:00:00 EST 2017},
month = {Tue Feb 07 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.118.060401

Citation Metrics:
Cited by: 12works
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  • Bell’s theorem states that some predictions of quantum mechanics cannot be reproduced by a local-realist theory. That conflict is expressed by Bell’s inequality, which is usually derived under the assumption that there are no statistical correlations between the choices of measurement settings and anything else that can causally affect the measurement outcomes. In previous experiments, this “freedom of choice” was addressed by ensuring that selection of measurement settings via conventional “quantum random number generators” was spacelike separated from the entangled particle creation. This, however, left open the possibility that an unknown cause affected both the setting choices and measurement outcomesmore » as recently as mere microseconds before each experimental trial. Here in this paper we report on a new experimental test of Bell’s inequality that, for the first time, uses distant astronomical sources as “cosmic setting generators.” In our tests with polarization-entangled photons, measurement settings were chosen using real-time observations of Milky Way stars while simultaneously ensuring locality. Assuming fair sampling for all detected photons, and that each stellar photon’s color was set at emission, we observe statistically significant ≳7.31σ and ≳11.93σ violations of Bell’s inequality with estimated p values of ≲1.8 × 10 -13 and ≲4.0 × 10 -33, respectively, thereby pushing back by ~600 years the most recent time by which any local-realist influences could have engineered the observed Bell violation.« less
  • This paper presents theoretical star formation and chemical enrichment histories for the stellar halo of the Milky Way (MW) based on new chemodynamical modeling. The goal of this study is to assess the extent to which metal-poor stars in the halo reflect the star formation conditions that occurred in halo progenitor galaxies at high redshift, before, and during the epoch of re-ionization. Simple prescriptions that translate dark-matter (DM) halo mass into baryonic gas budgets and star formation histories yield models that resemble the observed MW halo in its total stellar mass, metallicity distribution, and the luminosity function and chemical enrichmentmore » of dwarf satellite galaxies. These model halos in turn allow an exploration of how the populations of interest for probing the epoch of re-ionization are distributed in physical and phase space, and of how they are related to lower-redshift populations of the same metallicity. The fraction of stars dating from before a particular time or redshift depends strongly on radius within the galaxy, reflecting the 'inside-out' growth of cold DM halos, and on metallicity, reflecting the general trend toward higher metallicity at later times. These results suggest that efforts to discover stars from z>6-10 should select for stars with [Fe/H] approx<-3 and favor stars on more tightly bound orbits in the stellar halo, where the majority are from z>10 and 15%-40% are from z>15. The oldest, most metal-poor stars-those most likely to reveal the chemical abundances of the first stars-are most common in the very center of the Galaxy's halo: they are in the bulge, but not of the bulge. These models have several implications for the larger project of constraining the properties of the first stars and galaxies using data from the local universe.« less
  • We study the origin and properties of the population of unbound stars in the kinematic samples of dwarf spheroidal galaxies. For this purpose we have run a high resolution N- body simulation of a two-component dwarf galaxy orbiting in a Milky Way potential. In agreement with the tidal stirring scenario of Mayer et al., the dwarf is placed on a highly eccentric orbit, its initial stellar component is in the form of an exponential disk and it has a NFW-like dark matter halo. After 10 Gyrs of evolution the dwarf produces a spheroidal stellar component and is strongly tidally strippedmore » so that mass follows light and the stars are on almost isotropic orbits. From this final state, we create mock kinematic data sets for 200 stars by observing the dwarf in different directions.We find that when the dwarf is observed along the tidal tails the kinematic samples are strongly contaminated by unbound stars from the tails.We also study another source of possible contamination by adding stars from the Milky Way. We demonstrate that most of the unbound stars can be removed by the method of interloper rejection proposed by den Hartog & Katgert and recently tested on simulated dark matter haloes. We model the cleaned up kinematic samples using solutions of the Jeans equation with constant mass-to-light ratio and velocity anisotropy parameter. We show that even for such strongly stripped dwarf the Jeans analysis, when applied to cleaned samples, allows us to reproduce the mass and mass-to-light ratio of the dwarf with accuracy typically better than 25 percent and almost exactly in the case when the line of sight is perpendicular to the tidal tails. The analysis was applied to the new data for the Fornax dSph galaxy for which we find a mass-to-light ratio of 11 solar units and isotropic orbits. We demonstrate that most of the contamination in the kinematic sample of Fornax probably originates from the Milky Way.« less
  • As part of the Dwarf galaxies Abundances and Radial-velocities Team (DART) Programme, we have measured the metallicities of a large sample of stars in four nearby dwarf spheroidal galaxies (dSph): Sculptor, Sextans, Fornax and Carina. The low mean metal abundances and the presence of very old stellar populations in these galaxies have supported the view that they are fossils from the early Universe. However, contrary to naive expectations, we find a significant lack of stars with metallicities below [Fe/H] {approx} -3 dex in all four systems. This suggests that the gas that made up the stars in these systems hadmore » been uniformly enriched prior to their formation. Furthermore, the metal-poor tail of the dSph metallicity distribution is significantly different from that of the Galactic halo. These findings show that the progenitors of nearby dSph appear to have been fundamentally different from the building blocks of the Milky Way, even at the earliest epochs.« less
  • The structure and kinematics of the recognized stellar components of the Milky Way are explored, based on well-determined atmospheric parameters and kinematic quantities for 32360 'calibration stars' from the Sloan Digital Sky Survey (SDSS) and its first extension, SDSS-II, which included the sub-survey Sloan Extension for Galactic Understanding and Exploration (SEGUE). Full space motions for a sub-sample of 16,920 stars, exploring a local volume within 4 kpc of the Sun, are used to derive velocity ellipsoids for the inner- and outer-halo components of the Galaxy, as well as for the canonical thick-disk and proposed metal-weak thick-disk (MWTD) populations. This newmore » sample of calibration stars represents an increase of 60% relative to the numbers used in a previous analysis. We first examine the question of whether the data require the presence of at least a two-component halo in order to account for the rotational behavior of likely halo stars in the local volume, and whether more than two components are needed. We also address the question of whether the proposed MWTD is kinematically and chemically distinct from the canonical thick disk, and point out that the Galactocentric rotational velocity inferred for the MWTD, as well as its mean metallicity, appear quite similar to the values derived previously for the Monoceros stream, suggesting a possible association between these structures. In addition, we consider the fractions of each component required to understand the nature of the observed kinematic behavior of the stellar populations of the Galaxy as a function of distance from the plane. Scale lengths and scale heights for the thick-disk and MWTD components are determined. Spatial density profiles for the inner- and outer-halo populations are inferred from a Jeans theorem analysis. The full set of calibration stars (including those outside the local volume) is used to test for the expected changes in the observed stellar metallicity distribution function with distance above the Galactic plane in situ, due to the changing contributions from the underlying stellar populations. The above issues are considered, in concert with theoretical and observational constraints from other Milky-Way-like galaxies, in light of modern cold dark matter galaxy formation models.« less