# Single-shot energy measurement of a single atom and the direct reconstruction of its energy distribution

## TL;DR

This paper introduces a method for single-shot energy measurement of individual atoms, enabling direct energy distribution reconstruction in a single experimental run, with applications in ion traps and potential impacts on chemistry and collision studies.

## Contribution

The paper presents a novel technique for measuring the energy of a single atom in a single shot, allowing direct reconstruction of its energy distribution without extensive averaging.

## Key findings

- Energy measurement agrees within 5% with existing thermometry methods.
- Method distinguishes ion motion in different trap modes.
- Applicable for energies from 10 K and above.

## Abstract

An ensemble of atoms in steady-state, whether in thermal equilibrium or not, has a well defined energy distribution. Since the energy of single atoms within the ensemble cannot be individually measured, energy distributions are typically inferred from statistical averages. Here, we show how to measure the energy of a single atom in a single experimental realization (single-shot). The energy distribution of the atom over many experimental realizations can thus be readily and directly obtained. We apply this method to a single-ion trapped in a linear Paul trap for which energy measurement in a single-shot is applicable from 10 K and above. Our energy measurement agrees within 5% to a different thermometry method which requires extensive averaging. Apart from the total energy, we also show that the motion of the ion in different trap modes can be distinguished. We believe that this method will have profound implications on single particle chemistry and collision experiments.