A. Yu. Voronin

Study of the neutron quantum states in the gravity field

We have studied neutron quantum states in the potential well formed by the earths gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations with an experimental accuracy. A position-sensitive neutron detector with an extra-high spatial resolution of ~2 microns was developed and tested for this particular experiment, to be used to measure the spatial density distribution in a standing neutron wave above a mirror for a set of some of the lowest quantum states. The present experiment can be used to set an upper limit for an additional short-range fundamental force. We studied methodological uncertainties as well as the feasibility of improving further the accuracy of this experiment.

Constraint on the coupling of axionlike particles to matter via an ultracold neutron gravitational experiment

We present a new constraint for the axion monopole-dipole coupling in the range of

A method to measure the resonance transitions between the gravitationally bound quantum states of neutrons in the GRANIT spectrometer

1\text{ }\text{ }\ensuremath{\mu}\mathrm{m}

Quantum reflection of antihydrogen from the Casimir potential above matter slabs

\char21{}a few mm, previously unavailable for experimental study. The constraint was obtained using our recent results on the observation of neutron quantum states in the Earths gravitational field. We exploit the ultimate sensitivity of ultracold neutrons (UCN) in the lowest gravitational states above a material surface to any additional interaction between the UCN and the matter, if the characteristic interaction range is within the mentioned domain.

On the electromagnetic form factors of hadrons in the time-like region near threshold

We present a method to measure the resonance transitions between the gravitationally bound quantum states of neutrons in the GRANIT spectrometer. The purpose of GRANIT is to improve the accuracy of measurement of the quantum states parameters by several orders of magnitude, taking advantage of long storage of ultracold neutrons at specular trajectories. The transitions could be excited using a periodic spatial variation of a magnetic field gradient. If the frequency of such a perturbation (in the frame of a moving neutron) coincides with a resonance frequency defined by the energy difference of two quantum states, the transition probability will sharply increase. The GRANIT experiment is motivated by searches for short-range interactions (in particular spin-dependent interactions), by studying the interaction of a quantum system with a gravitational field, by searches for extensions of the Standard model, by the unique possibility to check the equivalence principle for an object in a quantum state and by studying various quantum optics phenomena.

Shaping the distribution of vertical velocities of antihydrogen in GBAR

We study quantum reflection of antihydrogen atoms from matter slabs due to the van der Waals/Casimir-Polder (vdW/CP) potential. By taking into account the specificities of antihydrogen and the optical properties and width of the slabs we calculate realistic estimates for the potential and quantum reflection amplitudes. Next we discuss the paradoxical result of larger reflection coefficients estimated for weaker potentials in terms of the Schwarzian derivative. We analyze the limiting case of reflections at small energies, which are characterized by a scattering length and have interesting applications for trapping and guiding antihydrogen using material walls.

Constraints on spin-dependent short-range interactions using gravitational quantum levels of ultracold neutrons

Abstract Hadron electromagnetic form factor in the time-like region at the boundary of the physical region is considered. The energy behavior of the form factor is shown to be determined by the strong hadron–antihadron interaction. We propose a simple phenomenological model of the h h ¯ interaction that describes the form factor behaviour in the region where scattering length approximation fails and estimate on its basis imaginary part of the scattering lengths (volumes) for Λ Λ ¯ , Λ Σ ¯ 0 ( Λ ¯ Σ 0 ) , Σ 0 Σ ¯ 0 and D ∗ D ∗ ¯ from present experimental data. The developed approach enables us to analyze the existence of baryon–antibaryon ( B B ¯ ) near threshold resonances. The experiments to extract detailed information on the near threshold B B ¯ interaction from hadron form factor energy behavior are suggested.

The whispering gallery effect in neutron scattering

GBAR is a project aiming at measuring the free-fall acceleration of gravity for antimatter, namely antihydrogen atoms (

Quantum reflection of antihydrogen from nanoporous media

\overline{\mathrm {H}}