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Left, schematics of the apparatus (positron beam, collimators, SiN gratings and emulsion detector. A HpGe detector is used as beam monitor). Right, single-particle interference visibility as a function of the positron energy is in agreement with quantum mechanics (blue) and disagrees with classical physics (orange dashed). Courtesy: Politecnico di Milano

 

Topics: Antimatter, High Energy Physics, Particle Physics, Quantum Mechanics


Researchers in Italy and Switzerland have performed the first ever double-slit-like experiment on antimatter using a Talbot-Lau interferometer and a positron beam.

The classic double-slit experiment confirmed that light and matter have the characteristics of both waves and particles, a duality that was first put forward by de Broglie in 1923. This superposition principle is one of the main postulates of quantum mechanics and researchers have since been able to diffract and interfere matter waves of objects of increasing complexity – from electrons to neutrons and molecules.

The QUPLAS (QUantum Interferometry and Gravitation with Positrons and LAsers) collaboration, which includes researchers from the Politecnico di Milano L-NESS in Como, the Milan unit of the Istituto Nazionale di Fisica Nucleare (INFN), the Università degli Studi di Milano and the University of Bern, has now performed the first interference experiment on positrons – the antimatter equivalent of electrons.

“The experiment was first proposed for electrons by Albert Einstein and Richard Feynman as a thought experiment and realized by Merli, Missiroli and Pozzi in 1976 and more systematically by Tonomura and colleagues in 1989,” explains QUPLAS spokesman Marco Giammarchi of the INFN. “In this original experiment, which was voted by Physics World as the most beautiful experiment, the researchers demonstrated the specifically quantum effect of single particle interference, which – according to Feynman – is the central ‘mystery’ of quantum theory.”

 

Antimatter quantum interferometry makes its debut, Belle Dumé, Physics World

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