Valery Nesvizhevsky

Gravitational Quantum States (GQS) and Whispering-Gallery Quantum (WGS) states of light neutral particles are a useful tool for high-precision measurements. Such quantum states of neutrons have been observed [1] and used ourdays by several research groups to constrain fundamental short-range interactions. Analogous states of ultracold atoms and antiatoms have been predicted [2]; they appear due to quantum reflection of ultracold (anti)atoms from surface [3]. Studies with hydrogen is the goal of a new GRASIAN collaboration.

Those with antihydrogen can be pursuit in the future by GBAR collaboration at CERN in more precise experiments, which test the equivalence principle with antimatter [4]. In all these cases, a long observation time thus a much better energy resolution and precision can be achieved in a novel Magneto-Gravitational Trap (MGT), where the particles will be trapped vertically by gravity and a mirror, and horizontally by a magnetic field [5]. The ultralow energies of (anti)atoms and long lifetimes of GQS provide unique conditions for precision gravitational, optical and hyperfine spectroscopy of (anti)atoms.

In this talk we will discuss some experimental and theoretical results as well as prospects of these activities

1. V.V. Nesvizhevsky et al, Quantum states of neutrons in the Earth’s gravitational field, Nature 415 (2002) 297; Neutron whispering gallery, Nature Phys. 6 (2010) 114.

2. A.Yu. Voronin et al, Gravitational quantum states of antihydrogen, Phys. Rev. A 83 (2011) 032903.

3. P.-P. Crepin et al, Quantum reflection of antihydrogen from a liquid helium bulk, Hyperf. Int. 240 (2019) 58.

4. P.-P. Crepin et al, Quantum interference test of the equivalence principle of antihydrogen, Phys. Rev. A 99 (2019) 042119.

5. V.V. Nesvizhevsky et al, A magneto-gravitational trap for precision studies of gravitational quantum states ), arXiv:200106332 (2020).