Quantum coherence recovery through Stern–Gerlach erasure

Abstract

Quantum erasure probes the dynamic nature of quantum coherence. It allows quantum systems to exhibit interference effects by recovering coherence that was previously lost through entanglement with another system. In this paper we examine the concept of a quantum eraser which creates and then erases path information through repeated use of the Stern–Gerlach effect. We explore the degree to which this eraser can recover quantum coherence. We find that the recovered coherence depends on the spin of the objects passing through the eraser and on the relative angle between the orientations of the eraser’s two magnets. We determine that full coherence can always be recovered for spin-1/2 objects independent of the value of the spin projection but cannot always be recovered for objects with larger spin values. We then discuss how the quantum coherence could be experimentally measured in this setup. Finally, we comment on the limitations of this Stern–Gerlach eraser and similar erasure schemes.

Demystifying the delayed-choice quantum eraser

“…The quantum eraser has now been experimentally realized by various people using photons [14][15][16][17][18][19][20][21][22][23][24]. There have been some other proposals using neutral kaons [25], via a modified Stern-Gerlach setup [26,27], and also using atoms in an optical Stern-Gerlach model [28]. The idea of the quantum eraser has also been generalized to three-path interference [29].…”

The Delayed-Choice Quantum Eraser Leaves No Choice

“…With the advances in experimental techniques the quantum eraser, with or without delayed-choice, was realized in various ways [15][16][17][18][19][20][21][22][23][24][25][26], and several other proposals were made [27][28][29][30]. It has also been demonstrated that the idea of quantum eraser should also work for three-path interference [31].…”