Nonlinear dynamics of antihydrogen in magnetostatic traps: implications for gravitational measurements

The influence of gravity on antihydrogen dynamics in magnetic traps is studied. The advantages and disadvantages of various techniques for measuring the ratio of the gravitational mass to the inertial mass of antihydrogen are discussed. Theoretical considerations and numerical simulations indicate that stochasticity may be especially important for some experimental techniques in vertically oriented traps.Comment: 12 pages, 9 figure

Nonlinear dynamics of anti-hydrogen in magnetostatic traps: Implications for gravitational measurements

The influence of gravity on anti-hydrogen dynamics in magnetic traps is studied. The advantages and disadvantages of various techniques for measuring the ratio of the gravitational mass to the inertial mass of anti-hydrogen are discussed. Theoretical considerations and numerical simulations indicate that stochasticity may be especially important for some experimental techniques in vertically oriented traps. © 2013 IOP Publishing Ltd

Using stochastic acceleration to place experimental limits on the charge of antihydrogen

Assuming hydrogen is charge neutral, CPT invariance demands that antihydrogen also be charge neutral. Quantum anomaly cancellation also demands that antihydrogen be charge neutral. Standard techniques based on measurements of macroscopic quantities of atoms cannot be used to measure the charge of antihydrogen. In this paper, we describe how the application of randomly oscillating electric fields to a sample of trapped antihydrogen atoms, a form of stochastic acceleration, can be used to place experimental limits on this charge. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft

An experimental limit on the charge of antihydrogen.

The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for antihydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) or gravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1 ± 3.4 mm for an average axial electric field of 0.51 V mm(-1). Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q=(-1.3 ± 1.1 ± 0.4) × 10(-8). Here, e is the unit charge, and the errors are from statistics and systematic effects

Limit on the electric charge of antihydrogen

A detailed description of systematic aspects of ALPHA's measurement showing that antihydrogen is electrically neutral