Idler-free channel position finding

TL;DR

This paper explores idler-free quantum protocols for channel position finding, which avoid the need for quantum memories, potentially simplifying implementation in quantum sensing and related applications.

Contribution

It introduces and applies an idler-free quantum protocol to channel position finding, expanding the toolkit for quantum sensing without requiring quantum memory.

Findings

Idler-free protocols can effectively locate channels in a sequence.

The approach simplifies quantum sensing setups by removing the need for quantum memories.

Potential applications include quantum spectroscopy and quantum reading.

Abstract

Entanglement is a powerful tool for quantum sensing, and entangled states can greatly boost the discriminative power of protocols for quantum illumination, quantum metrology, or quantum reading. However, entangled state protocols generally require the retention of an idler state, to which the probes are entangled. Storing a quantum state is difficult and so technological limitations can make protocols requiring quantum memories impracticable. One alternative is idler-free protocols that utilise non-classical sources but do not require any idler states to be stored. Here we apply such a protocol to the task of channel position finding. This involves finding a target channel in a sequence of background channels, and has many applications, including quantum sensing, quantum spectroscopy, and quantum reading.