• Editors' Suggestion

Quantum Delayed-Choice Experiment with a Beam Splitter in a Quantum Superposition

Shi-Biao Zheng, You-Peng Zhong, Kai Xu, Qi-Jue Wang, H. Wang, Li-Tuo Shen, Chui-Ping Yang, John M. Martinis, A. N. Cleland, and Si-Yuan Han
Phys. Rev. Lett. 115, 260403 – Published 28 December 2015
PDFHTMLExport Citation

Abstract

A quantum system can behave as a wave or as a particle, depending on the experimental arrangement. When, for example, measuring a photon using a Mach-Zehnder interferometer, the photon acts as a wave if the second beam splitter is inserted, but as a particle if this beam splitter is omitted. The decision of whether or not to insert this beam splitter can be made after the photon has entered the interferometer, as in Wheeler’s famous delayed-choice thought experiment. In recent quantum versions of this experiment, this decision is controlled by a quantum ancilla, while the beam splitter is itself still a classical object. Here, we propose and realize a variant of the quantum delayed-choice experiment. We configure a superconducting quantum circuit as a Ramsey interferometer, where the element that acts as the first beam splitter can be put in a quantum superposition of its active and inactive states, as verified by the negative values of its Wigner function. We show that this enables the wave and particle aspects of the system to be observed with a single setup, without involving an ancilla that is not itself a part of the interferometer. We also study the transition of this quantum beam splitter from a quantum to a classical object due to decoherence, as observed by monitoring the interferometer output.

  • Figure
  • Figure
  • Figure
  • Received 11 August 2015

DOI:https://doi.org/10.1103/PhysRevLett.115.260403

© 2015 American Physical Society

Authors & Affiliations

Shi-Biao Zheng1,*, You-Peng Zhong2, Kai Xu2, Qi-Jue Wang2, H. Wang2, Li-Tuo Shen1, Chui-Ping Yang3, John M. Martinis4,†, A. N. Cleland5,‡, and Si-Yuan Han6,7

  • 1Department of Physics, Fuzhou University, Fuzhou 350116, China
  • 2Department of Physics, Zhejiang University, Hangzhou 310027, China
  • 3Department of Physics, Hangzhou Normal University, Hangzhou 310036, China
  • 4Department of Physics, University of California, Santa Barbara, California 93106, USA
  • 5Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
  • 6Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA
  • 7Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • *t96034@fzu.edu.cn
  • martinis@physics.ucsb.edu
  • anc@uchicago.edu

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 115, Iss. 26 — 31 December 2015

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×