Related papers: Support for Gravitationally-Attractive Composite A…
The production of antihydrogen by several research groups provides the opportunity to measure the gravitational behaviour of antimatter in the gravitational field of the Earth. The predictions in the literature range from normal attraction…
By combining general relativity and CPT symmetry, the theory of CPT gravity predicts gravitational repulsion between matter and CPT-transformed matter, i.e. antimatter inhabiting an inverted space-time. Such repulsive gravity turned out to…
There has been renewed interest in the idea of antigravity -- that matter and antimatter repel gravitationally - in lieu of the recent beautiful ALPHA-g result for the free-fall acceleration of antihydrogen of $a_{\bar{H}}=(0.75\pm…
In arXiv:2401.10954 I showed that, in the context of antigravity (i.e., matter and antimatter repel gravitationally), quark/lepton mass-energy is matter and antiquark/antilepton mass-energy is antimatter while the mass-energy of the…
The ALPHA collaboration (of which I am a member) has made great strides recently in trapping antihydrogen and starting down the path of making spectroscopic measurements. The primary goal of the experiment is to test CPT invariance but…
Certain modern theories of gravity predict that antimatter will fall differently than matter in the Earth's gravitational field. However, no experimental tests of gravity on antimatter exist and all conclusions drawn from experiments on…
Until now, there is no experimental evidence on the gravitational behaviour of antimatter. While we may be confident that antimatter attracts antimatter, we do not know anything on the interaction between matter and antimatter. We…
We know that the generally accepted theories of gravity and quantum mechanics are fundamentally incompatible. Thus, when we try to combine these theories, we must beware of physical pitfalls. Modern theories of quantum gravity are trying to…
A number of experiments are currently underway on antimatter, particularly anti-hydrogen, to test whether the fundamental interactions behave the same way as for matter. Here we present a simple argument showing that a bound on a difference…
The aim of this brief review is twofold. First, we give an overview of the unprecedented experimental efforts to measure the gravitational acceleration of antimatter; with antihydrogen in three competing experiments at CERN (AEGIS, ALPHA…
In a paper by Villata (2011), the possibility of a repulsive gravitational interaction between antimatter and ordinary matter was discussed. The author argued that this anti-gravity can be regarded as a prediction of general relativity,…
The gravitational behavior of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. We investigate this issue on…
This review is motivated by the first result of the ALPHA-g experiment at CERN, which indicates that atoms and anti-atoms have different gravitational charges; according to measurements, the gravitational acceleration of anti-atoms is only…
Whereas repulsive gravity was considered as a fringe concept until the mid-1990's, the growingexperimental evidence since this epoch for repulsive gravity, in what is now called Dark Energy,for lack of a better understanding of its nature,…
More recently, the ALPHA-g experiment has shown that antiatoms fall in the Earth's gravitational field like ordinary atoms, with the non-negligible possibility that antiatoms fall with a slightly lower acceleration. A possible lower…
The universality of free fall, the weak equivalence principle (WEP), is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the…
The AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment, located at the Antimatter Factory at CERN, aims to study the asymmetry between matter and antimatter. In particular, its first goal is to measure the…
In light of recent experimental proposals to measure the free fall acceleration of antihydrogen in the earth's gravitational field, we investigate the bounds that existing experiments place on any asymmetry between the free fall of matter…
We present a theoretical study of the motion of the antihydrogen atom ($\bar{H}$) in the Earth's gravitational field above a material surface. We predict that $\bar{H}$ atom, falling in the Earth's gravitational field above a material…
The proposed Antihydrogen Gravity experiment at Fermilab (P981) will directly measure the gravitational attraction ("gbar") between antihydrogen and the Earth, with an accuracy of 1% or better. The following key question has been asked by…