Josephson Ring Modulator Sum-Frequency Circuit for Remote Entanglement
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Solution Overview
Problem
Existing quantum communication technologies face challenges with entanglement swapping due to multipair emission from spontaneous parametric down-conversion sources, reducing fidelity and being incompatible with device-independent quantum key distribution schemes, and suffering from detection loopholes in Bell's inequality tests.
Innovation Solution
A sum frequency generator in the microwave domain is used, comprising a Josephson ring modulator and resonators configured to up-convert photons, enabling remote entanglement of qubits and operating as a nonlinear filter to improve entanglement swapping protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spontaneous parametric down-conversion sources are used for entanglement swapping, then entanglement generation is achieved, but multipair emission reduces fidelity and creates detection loopholes
Solution Approach 1:
The patent extracts and eliminates the harmful multipair emission component from the entanglement generation process by using sum frequency generation to convert single-photon inputs into entangled photon pairs, thereby removing the multipair emission problem inherent in spontaneous parametric down-conversion while maintaining entanglement generation capability
Solution Approach 2:
The sum frequency generation process acts as an intermediary mechanism that receives single photons from quantum dots and converts them into entangled photon pairs, serving as a mediator that transforms the input state while eliminating the detection loopholes associated with direct down-conversion methods
2Reliability
If sum frequency generation is used to up-convert photons, then entanglement fidelity is enhanced and detection loopholes are closed, but device complexity increases
Solution Approach 1:
The sum frequency generation device performs multiple functions simultaneously: it up-converts photon frequencies, generates entangled states, and eliminates detection loopholes, making a single complex component that accomplishes what would otherwise require multiple separate systems
Solution Approach 2:
The patent changes the frequency parameter of the input photons through sum frequency generation, converting microwave or infrared photons into visible or near-infrared photons, thereby enabling the use of high-efficiency detectors and closing detection loopholes while maintaining quantum state integrity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sum frequency generator enhances entanglement fidelity, closes detection loopholes, and supports secure quantum communication by generating a heralded entangled state, facilitating remote entanglement and quantum key distribution.
Implementation Method 1
a sum frequency generator in the microwave domain is used, comprising a Josephson ring modulator and resonators configured to up-convert photons
Implementation Method 2
comprising a Josephson ring modulator
Implementation Method 3
resonators configured to up-convert photons
Data Source
AI summary
A technique relates to a circuit for a sum frequency generator. A first resonator is connected to a Josephson ring modulator (JRM), and the first resonator is configured to receive a first photon at a first frequency. A second resonator is connected to the JRM, and the second resonator is configured to have a first harmonic and no second harmonic. The second resonator is configured to receive a second photon at a second frequency, and the first resonator is configured to output an up-converted photon. The up-converted photon has an up-converted frequency that is a sum of the first frequency and the second frequency.