Abstract
The quantum statistics of bosons and fermions manifest themselves in the manner in which two indistinguishable particles interfere quantum mechanically. When two photons, which are bosonic particles, enter a beam-splitter with one photon in each input port, they bunch together at either of the two output ports. The corresponding disappearance of the coincidence count is the Hong–Ou–Mandel effect1. Here we show the phonon counterpart of this effect in a system of trapped-ion phonons, which are collective excitations derived by quantizing vibrational motions that obey Bose–Einstein statistics. We realize a beam-splitter transformation of the phonons by employing the mutual Coulomb repulsion between ions, and perform a two-phonon quantum interference experiment using that transformation. We observe an almost perfect disappearance of the phonon coincidence between two ion sites, confirming that phonons can be considered indistinguishable bosonic particles. The two-particle interference demonstrated here is purely a quantum effect, without a classical counterpart, hence it should be possible to demonstrate the existence of entanglement on this basis. We attempt to generate an entangled state of phonons at the centre of the Hong–Ou–Mandel dip in the coincidence temporal profile, under the assumption that the entangled phonon state is successfully generated if the fidelity of the analysis pulses is taken into account adequately. Two-phonon interference, as demonstrated here, proves the bosonic nature of phonons in a trapped-ion system. It opens the way to establishing phonon modes as carriers of quantum information in their own right2,3,4, and could have implications for the quantum simulation of bosonic particles5,6 and analogue quantum computation via boson sampling7.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Two-photon interferences of weak coherent lights
Scientific Reports Open Access 15 October 2021
-
Experimental interference of uncorrelated photons
Scientific Reports Open Access 05 December 2019
-
Two-photon interference of polarization-entangled photons in a Franson interferometer
Scientific Reports Open Access 18 July 2017
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout




References
Hong, C. K., Ou, Z. Y. & Mandel, L. Measurement of subpicosecond time intervals between 2 photons by interference. Phys. Rev. Lett. 59, 2044–2046 (1987)
Brown, K. R. et al. Coupled quantized mechanical oscillators. Nature 471, 196–199 (2011)
Harlander, M., Lechner, R., Brownnutt, M., Blatt, R. & Hänsel, W. Trapped-ion antennae for the transmission of quantum information. Nature 471, 200–203 (2011)
Haze, S., Tateishi, Y., Noguchi, A., Toyoda, K. & Urabe, S. Observation of phonon hopping in radial vibrational modes of trapped ions. Phys. Rev. A 85, 031401(R) (2012)
Porras, D. & Cirac, J. I. Bose-Einstein condensation and strong-correlation behavior of phonons in ion traps. Phys. Rev. Lett. 93, 263602 (2004)
Toyoda, K., Matsuno, Y., Noguchi, A., Haze, S. & Urabe, S. Experimental realization of a quantum phase transition of polaritonic excitations. Phys. Rev. Lett. 111, 160501 (2013)
Shen, C., Zhang, Z. & Duan, L. M. Scalable implementation of boson sampling with trapped ions. Phys. Rev. Lett. 112, 050504 (2014)
Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S. & Yamamoto, Y. Indistinguishable photons from a single-photon device. Nature 419, 594–597 (2002)
Beugnon, J. et al. Quantum interference between two single photons emitted by independently trapped atoms. Nature 440, 779–782 (2006)
Kaltenbaek, R., Blauensteiner, B., Zukowski, M., Aspelmeyer, M. & Zeilinger, A. Experimental interference of independent photons. Phys. Rev. Lett. 96, 240502 (2006)
Maunz, P. et al. Quantum interference of photon pairs from two remote trapped atomic ions. Nature Phys. 3, 538–541 (2007)
Lang, C. et al. Correlations, indistinguishability and entanglement in Hong–Ou–Mandel experiments at microwave frequencies. Nature Phys. 9, 345–348 (2013)
Kaufman, A. M. et al. Two-particle quantum interference in tunnel-coupled optical tweezers. Science 345, 306–309 (2014)
Lopes, R. et al. Atomic Hong–Ou–Mandel experiment. Nature 520, 66–68 (2015)
Liu, R. C., Odom, B., Yamamoto, Y. & Tarucha, S. Quantum interference in electron collision. Nature 391, 263–265 (1998)
Bocquillon, E. et al. Coherence and indistinguishability of single electrons emitted by independent sources. Science 339, 1054–1057 (2013)
Knill, E., Laflamme, R. & Milburn, G. J. A scheme for efficient quantum computation with linear optics. Nature 409, 46–52 (2001)
Moehring, D. L. et al. Entanglement of single-atom quantum bits at a distance. Nature 449, 68–71 (2007)
Cirac, J. I. & Zoller, P. Quantum computations with cold trapped ions. Phys. Rev. Lett. 74, 4091–4094 (1995)
Mølmer, K. & Sørensen, A. Multiparticle entanglement of hot trapped ions. Phys. Rev. Lett. 82, 1835–1838 (1999)
Sackett, C. A. et al. Experimental entanglement of four particles. Nature 404, 256–259 (2000)
Broome, M. A. et al. Photonic boson sampling in a tunable circuit. Science 339, 794–798 (2013)
Spring, J. B. et al. Boson sampling on a photonic chip. Science 339, 798–801 (2013)
Tillmann, M. et al. Experimental boson sampling. Nature Photon. 7, 540–544 (2013)
Crespi, A. et al. Integrated multimode interferometers with arbitrary designs for photonic boson sampling. Nature Photon. 7, 545–549 (2013)
Aspelmeyer, M., Kippenberg, T. J. & Marquard, F. Cavity optomechanics. Rev. Mod. Phys. 86, 1391–1452 (2014)
Acknowledgements
We thank Y. Yamamoto for suggestions made at the early stages of this study, and K. Hayasaka for comments on the manuscript. This work was supported by JSPS KAKENHI, grant number 26400418.
Author information
Authors and Affiliations
Contributions
S.U., K.T. and A.N. designed this study. A.N. and R.H. conducted the experiment. R.H. wrote an early version of the manuscript. K.T. revised and completed the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Rights and permissions
About this article
Cite this article
Toyoda, K., Hiji, R., Noguchi, A. et al. Hong–Ou–Mandel interference of two phonons in trapped ions. Nature 527, 74–77 (2015). https://doi.org/10.1038/nature15735
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature15735
This article is cited by
-
Let the ions sing
Nature Physics (2023)
-
Two electrons interacting at a mesoscopic beam splitter
Nature Nanotechnology (2023)
-
Scalable and programmable phononic network with trapped ions
Nature Physics (2023)
-
Two-photon interferences of weak coherent lights
Scientific Reports (2021)
-
Hong–Ou–Mandel interference depends on the method of erasing the beam path information
Journal of the Korean Physical Society (2021)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.