QUantum interferometry and gravity with Positrons and LASers

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04.12.19:  The antimatter interferometry experiment performed in our laboratory is one of the Top 10 Breakthrough 2019 (physicsword).

03.05.19:  First demonstration of antimatter wave interferometry by S. Sala, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, M. Leone, C. Pistillo and P. Scampoli

Brief description of this work: Italian (breve descrizione in italiano)
Spanish (breve descripción en castellano)

The scientific goal of the QUPLAS (QUantum interferometry and gravity with Positrons and LASers) antimatter experiment is the opening of two new fields of investigation in modern particle physics: antimatter interferometry, using both an elementary antiparticle (the positron, e+) and a bound e+/e- state (positronium, Ps), to test the validity of the fundamental CPT symmetry, and gravitation studies with positronium, an innovative way to inspect the Weak Equivalence Principle with a particle/antiparticle symmetric system.

Animation based on actual data

The first stage of the experiment aims at the comparison of positrons and electrons interference, to compare for the first time the quantum interferometry pattern of a particle with the one of its own antiparticle. To achieve this goal, a dedicated interferometer is being assembled at the VEPAS (Variable Energy Positron Annihilation Spectroscopy) positron beamline located at the L-NESS (Laboratory for Nanostructure Epitaxy and Spintronics on Silicon) Laboratory of the Politecnico di Milano in Como (Italy).

Simone Sala

   Rafael Ferragut and Marco Leone


Experimental set-up

Ciro Pistillo and Marco Giammarchi

Elena Tonello, Stefano Aghion and Francesco Barantani (2016)

One of the gratings that are used in the QUPLAS experiment for positron interferometer

Micrograph of the emulsion containing the open regions of one of the gratings.

Partial view of the positron interferometer: 1) Vacuum chamber containing the interferometer and the mu-metal shield. 2) Vacuum system. 3) x-y stage moving the absorbing target for beam size measurement. 4) Viewport for laser alignment. 5) BaF2 detector. 6) Beam control electronics. 7) Bellows used for the alignment of the interferometer chamber.

A continuous positron beam is used to produce Talbot-Lau interference by means of micrometric gratings. The particle detection relies on the employment of emulsion based high-precision position detectors, which are being developed by the physicists of the Bern group in QUPLAS. Pictures of the first interferometer prototype and the micrometric gratings are presented in this page.
An intensive R&D program has been conducted by the whole collaboration to assess the detectability of very low energy particles with emulsions and the capability to detect positrons at the keV energy scale has been successfully demonstrated.

QUPLAS Spokesperson: M.Giammarchi, INFN Milano

More details available in these articles:

  1. S. Sala, F. Castelli, M. Giammarchi, S. Siccardi, S. Olivares. Matter-wave interferometry: towards antimatter interferometersJ. Phys. B: At. Mol. Opt. Phys. 48, 195002 (2015) doi: 10.1088/0953-4075/48/19/195002 pdf
  2. S. Sala, M. Giammarchi, S. Olivares. Asymmetric Talbot-Lau interferometry for inertial sensingPhys. Rev. A 94, 033625 (2016) doi: 10.1103/PhysRevA.94.033625 pdf
  3. S. Aghion, A. Ariga, T. Ariga, M. Bollani, E. Dei Cas, A. Ereditato, C. Evans, R. Ferragut, M. Giammarchi, C. Pistillo, M. Romé, S. Sala, and P. Scampoli. Detection of low energy antimatter with emulsions. JINST 11 P06017 (2016) doi: 10.1088/1748-0221/11/06/P06017 pdf
  4. S. Aghion, A. Ariga, M. Bollani, A. Ereditato, R. Ferragut, M. Giammarchi, M. Lodari, C. Pistillo, S. Sala, P. Scampoli, and M. Vladymyrov. Nuclear emulsions for the detection of micrometric-scale fringe patterns: an application to positron interferometryJINST 13, P05013 (2018) doi: 10.1088/1748-0221/13/05/P05013  pdf
  5. S. Sala, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, M. Leone, C. Pistillo, P. Scampoli. First demonstration of antimatter wave interferometryScience Adv. (I.F.: 12.8045eaav7610 (2019) doi: 10.1126/sciadv.aav7610  pdf
  6. L. Anzi, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, G. Maero, C. Pistillo, M. Romé, P. Scampoli, V. Toso. Sensitivity of emulsion detectors to low energy positronsJINST 15, P03027 (2020) doi: 10.1088/1748-0221/15/03/P03027 pdf
  7. A.Ariga, S.Cialdi, G.Costantini, A.Ereditato, R.Ferragut, M.Giammarchi, M.Leone, G.Maero, L.Miramonti, C.Pistillo, M.Romé, S.Sala, P.Scampoli, V.Toso, The QUPLAS experimental apparatus for antimatter interferometryNucl. Instrum. Methods Phys. Res. A 951, 163019 (2020) doi: 10.1016/j.nima.2019.163019 pdf

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