Efficient generation of large number-path entanglement using only linear optics and feed-forward

Area of Science:

• Quantum Optics
• Quantum Information Science

Background:

• Generating complex quantum states like N00N states is crucial for advancing quantum technologies.
• Existing methods for N00N state generation face scalability challenges.

Purpose of the Study:

• To develop an efficient and scalable measurement-based procedure for generating N00N states.
• To explore the use of photon detection and feed-forward for quantum state manipulation.

Main Methods:

• An idealized measurement procedure involving photon detection at beam splitter output ports.
• Utilizing feed-forward of measurement results to control photon states.
• Describing linear-optical circuits for state orthogonalization and N00N state conversion.

Main Results:

• A method to condense photons from two modes into one using measurement.
• Efficient generation of N00N states by directing photons to the same port with high probability.
• Production of macroscopic quantum superposition states via simultaneous photon detection.

Conclusions:

• The proposed approach offers an exponentially better scaling compared to existing methods.
• This technique provides a viable pathway for practical quantum imaging and metrology.
• The method enables efficient creation of superposition states essential for quantum information processing.