Abstract
Abstract
A recent trapped-ion experiment has realised a lattice gauge theory in which the internal states of the ions carry the gauge field and their vibrations carry bosonic matter. Tt observed a charge moving around a loop being frozen in place by Aharonov–Bohm interference. The noise of such a device is usually simulated after the fact. Here we show that it can be predicted in advance. For each quantity the experiment measures we derive, from the reported noise rates alone, a formula for how it decays and a bound that it can never exceed. Because the local conservation law of the theory is a parity of the vibrational mode, heating violates it at a rate that grows as the mode warms, so the violation accelerates rather than accumulating steadily. At zero electric field the three noise processes of the device leave three different fingerprints. Heating affects only the conservation law, motional dephasing affects only the interference, and qubit errors affect only the stored flux and the frozen state. Furthermore, with the field switched on, we provide an exact formula and a guaranteed bound for the escape from the frozen state.