Observation of broadband entanglement in microwave radiation from the dynamical Casimir effect.

ORAL

Abstract

A fundamental property of the quantum vacuum is that a time-varying boundary condition for the electro-magnetic field can generate photon pairs from the vacuum; this is called the Dynamical Casimir Effect (DCE)1. Quantum theory predicts that these photon pairs are entangled and that the resulting electromagnetic field is in a nonclassical state. We use a SQUID at the end of an open transmission line to realize a magnetic-flux-tunable boundary condition, and generate wideband DCE radiation2 by modulating the magnetic flux. The circuit noise and gain is calibrated by using the same SQUID as a shot noise tunnel junction. After calibration, we measure and analyze the covariance matrix for the DCE radiation at two different frequencies which add up to the pump frequency. We calculate the logarithmic negativity, and show two-mode squeezing below the vacuum, indicating entanglement. We furthermore estimate a potentially usable generation rate of 90 mega-entangled bits per second (Mebit s-1) at the sample, applicable for detection schemes3 or to entangle quibits4.

[1] G. T. Moore, J. Math. Phys. 11, 2679 (1970).
[2] C. M. Wilson et al.: Nature 479, nature10561 (2011)
[3] P. B. Dixon et al.: Phys. Rev. A 83, 051803 (2011)
[4] S. Felicetti et al.: Phys. Rev. Lett. 113, 093602 (2014)

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Presenters

  • Ben Schneider

    Microtechnology and Nanoscience (MC2), Chalmers University of Technology

Authors

  • Ben Schneider

    Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Andreas Bengtsson

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Ida-Maria Svensson

    Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Thomas Aref

    Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology

  • Göran Johansson

    Chalmers Univ of Tech, Chalmers University of Technology, Applied Quantum Physics Laboratory, Department of Nanotechnology and Nanoscience (MC2), Chalmers Univ of Tech, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Jonas Bylander

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Per Delsing

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology