TEM at Millikelvin Temperatures: Observing and Utilizing Superconducting Qubits

TL;DR

This paper advocates for developing a millikelvin-temperature transmission electron microscope (TEM) leveraging superconducting quantum circuitry, exploring quantum phenomena observation, and discussing potential applications and engineering challenges.

Contribution

It introduces new ideas for observing quantum states with TEM at millikelvin temperatures and reports ongoing experimental efforts towards this goal.

Findings

Potential to observe superposed electromagnetic fields around superconducting qubits

Proposal for TEM observation of microwave photons in quantum states

Discussion of low dose electron microscopy beyond quantum limits

Abstract

We present a case for developing a millikelvin-temperature transmission electron microscope (TEM). We start by reviewing known reasons for such development, then present new possibilities that have been opened up by recent progress in superconducting quantum circuitry, and finally report on our ongoing experimental effort. Specifically, we first review possibilities to observe a quantum mechanically superposed electromagnetic field around a superconducting qubit. This is followed by a new idea on TEM observation of microwave photons in an unusual quantum state in a resonator. We then proceed to review potential applications of these phenomena, which include low dose electron microscopy beyond the standard quantum limit. Finally, anticipated engineering challenges, as well as the authors' current ongoing experimental effort towards building a millikelvin TEM are described. In addition, we provide a brief introduction to superconducting circuitry in the Appendix for the interested reader who is not familiar with the subject.