Abstract: Systems and methods for generating an entangled pair of bichromatic photons are described. The system includes an atomic vapor cell containing atoms of an atomic species located within beam paths of a first and second laser beam. The first and second laser beams are tuned to first and second wavelengths that are resonant with first and second atomic transitions of the atomic species such that the first and second laser beams cause a four-wave mixing process within the atomic vapor cell. As a result of the four-wave mixing process, entangled photon pairs having a third and fourth wavelength are generated and output from the atomic vapor cell. The first and second wavelengths may be selected to create electromagnetically-induced transparency (EIT) within the atomic vapor cell, the EIT creating a transparent medium within the atomic vapor cell at the third wavelength, improving spectral brightness and/or photon linewidths.

Abstract: Techniques for facilitation the storage and retrieval of the qubits in a hot atomic vapor system are described herein. The techniques comprising, transmitting a first control pulse having a bandwidth that is based on a bandwidth of the optical qubit to modify transmission properties of the atomic vapor system: receiving the optical qubit at the atomic vapor system; transmitting a second control pulse having properties based on a target bandwidth for a retrieved optical qubit to modify transmission properties of the atomic vapor system; and isolating the retrieved optical qubit from the control laser.

Abstract: Techniques for reducing the number of detectors required to perform the measurements associated with quantum entanglement and quantum communication using optical qubits are described herein. The techniques comprise using delay lines between beam splitting optical elements to delay the arrival of photons at a detector such that a shared detector can be used to detect multiple photons for a correlation measurement with the detections occurring at different times. Thereby reducing the hardware requirements for the detectors by half and substantially reducing the cost and complexity of systems to detect and process qubits.

Abstract: Provided herein are systems and methods for implementing a field-deployable quantum memory. The quantum memory device includes a device housing configured to be rack-mounted and a quantum memory module disposed within the device housing and configured to perform a memory operation including storing an input qubit and retrieving the stored qubit for output. The quantum memory device may also include a filter module disposed within the device housing and configured to filter an output of the quantum memory module.

Abstract: A quantum memory device and methods for storage and retrieval of a qubit from the quantum memory device are described. The quantum memory device includes a first optical component to convert an input qubit encoded in an arbitrary polarization state of a photon into a spatial qubit propagating in a pair of parallel optical rails, an atomic vapor memory to store the spatial qubit in an atomic vapor, and a second optical component to combine the spatial qubit, when retrieved from the atomic vapor memory, into an output qubit encoded in an arbitrary polarization state of a photon.

Abstract: Systems and methods for generating an entangled pair of bichromatic photons are described. The system includes an atomic vapor cell containing atoms of an atomic species located within beam paths of a first and second laser beam. The first and In second laser beams are tuned to first and second wavelengths that are resonant with first and second atomic transitions of the atomic species such that the first and second laser beams cause a four-wave mixing process within the atomic vapor cell. As a result of the four-wave mixing process, entangled photon pairs having a third and fourth wavelength are generated and output from the atomic vapor cell. The first and second wavelengths may be selected to create electromagnetically-induced transparency (BIT) within the atomic vapor cell, the BIT creating a transparent medium within the atomic vapor cell at the third wavelength, improving spectral brightness and/or photon linewidths.

Abstract: A quantum memory device and methods for storage and retrieval of a qubit from the quantum memory device are described. The quantum memory device includes a first optical component to convert an input qubit encoded in an arbitrary polarization state of a photon into a spatial qubit propagating in a pair of parallel optical rails, an atomic vapor memory to store the spatial qubit in an atomic vapor, and a second optical component to combine the spatial qubit, when retrieved from the atomic vapor memory, into an output qubit encoded in an arbitrary polarization state of a photon.