Storage and conversion of quantum-statistical properties of light in the resonant quantum memory on tripod atomic configuration

TL;DR

This paper theoretically explores a broadband quantum memory using a resonant tripod atomic configuration, enabling simultaneous multi-channel storage and manipulation of quantum states of light, including entanglement and squeezing.

Contribution

It introduces a novel tripod atomic configuration for quantum memory that allows simultaneous multi-channel storage and advanced quantum state manipulation.

Findings

Quantum properties are preserved during simultaneous readout.

The scheme enables conversion of squeezed states into entangled pulses.

Sequential reading/writing opens new quantum information processing possibilities.

Abstract

We have considered theoretically the feasibility of the broadband quantum memory based on the resonant tripod-type atomic configuration. In this case, the writing of a signal field is carried out simultaneously into two channels, and characterized by an excitation of two spin waves of the atomic ensemble. With simultaneous read out from both channels quantum properties of the original signal are mapped on the retrieval pulse no worse than in the case of memory based on Lambda-type atomic configuration. At the same time new possibilities are opened up for manipulation of quantum states associated with sequential reading out (and/or sequential writing) of signal pulses. For example, the pulse in squeezed state is converted into two partially entangled pulses with partially squeezed quadratures. Alternatively, two independent signal pulses with orthogonal squeezed quadratures can be converted into two entangled pulses.