Echo-Ramsey Interferometry with Motional Quantum States

TL;DR

This paper presents a matter wave Ramsey interferometer using motional quantum states in an optical lattice, employing a band echo technique to significantly extend coherence time and identify thermal fluctuations as a key decoherence mechanism.

Contribution

It introduces a novel echo-Ramsey interferometer for motional states and demonstrates enhanced coherence time using repeated $$-pulses, advancing quantum state control.

Findings

Coherence time increased by an order of magnitude with band echo technique.

Thermal fluctuations identified as main decay mechanism.

Potential applications in quantum many-body dynamics and qubit manipulation.

Abstract

Ramsey interferometers (RIs) using internal electronic or nuclear states find wide applications in science and engineering. We develop a matter wave Ramsey interferometer for motional quantum states exploiting the S- and D-bands of an optical lattice and identify the different de-phasing and de-coherence mechanisms. We implement a band echo technique, employing repeated $\pi$-pulses. This suppresses the de-phasing evolution and significantly increase the coherence time of the motional state interferometer by one order of magnitude. We identify thermal fluctuations as the main mechanism for the remaining decay contrast. Our demonstration of an echo-Ramsey interferometer with motional quantum states in an optical lattice has potential application in the study of quantum many body lattice dynamics, and motional qubits manipulation.