### Related Experimental Research

###### The AEGIS project at CERN

The AEGIS project is aimed at establishing the coupling of antimatter with the gravitational field of the earth. For that matter, a beam of antihydrogen will be used.

###### The GBAR project at CERN

The GBAR project aims to test the equivalence principle, which equates gravitational mass and inertial mass, by measuring the gravitational acceleration of ultracold antihydrogen obtained from
deionizing H^{+}.

###### The ALPHA project at CERN

The ALPHA project aims to probe antimatter gravity, by observing whether trapped antihydrogen falls up or down when it is released.

###### Upcoming project at the PSI (Villingen, CH)

A project has been proposed to determine the gravitational properties of antimatter by experiments with muonium at the LTP.

###### Planned facility: FLAIR in Darmstadt

There are plans for a new facility (FLAIR), where the gravitation of antimatter is to be established by measuring the free fall of trapped and laser-cooled antihydrogen.

### Related Theoretical Research

###### Antigravity from extending General Relativity with the CPT theorem

The Italian scientist Massimo Villata has derived an equation that gives a classical description of a matter-antimatter gravitational repulsion. This theory can be used as a starting point in astronomy to explain large scale structures of the universe with gravitational repulsion.

###### The quantum vacuum as a fluid of gravitational dipoles

The physicist Dragan Hajdukovic from CERN postulates that the vacuum is a stream of virtual particle/antiparticle-pairs popping in and out of existence. Assuming like inertial mass but opposite gravitational mass for matter and antimatter, Hajdukovic intends to apply his theory to solve the dark energy problem.

###### The Dirac-Milne universe

The French physicists Alain Benoit-Levy and Gabriel Chardin study the cosmology of a universe, called: the Dirac-Milne universe, in which matter and antimatter are equally abundant but have opposite gravitational mass.

###### Dipolar dark matter

The French physicist Luc Blanchet considers an ontology in which dark matter is endowed with a gravitational dipole, to reproduce the MOND phenomenolgy.