Efficient noiseless linear amplification for light fields with larger amplitudes.

Area of Science:

• Quantum optics
• Quantum information science

Background:

• Linear amplification of quantum states is crucial for quantum technologies.
• Existing methods like photon addition-annihilation are limited to weak light fields.

Purpose of the Study:

• To investigate a novel scheme for non-deterministic noiseless linear amplification of coherent states.
• To compare the efficiency of different amplification strategies for various light field amplitudes.

Main Methods:

• Utilizing successive photon addition, denoted as (â†)², for amplification.
• Comparing (â†)² with photon addition-annihilation (ââ†) and combinatorial amplifications.
• Analyzing amplification performance based on equivalent input noise and coherent state amplitude |α|.

Main Results:

• The (â†)² operation is a more efficient amplifier than â↠for |α| ≳ 0.91.
• (ââ†)², ↲, and â†⁴ show strongest noiseless properties for |α| ≲ 0.51, 0.51 ≲ |α| ≲ 1.05, and |α| ≳ 1.05, respectively.
• The (â†)² operation effectively amplifies superpositions of coherent states.

Conclusions:

• This work provides efficient schemes for noiseless amplification of light fields with medium and large amplitudes.
• The proposed methods advance the development of quantum amplifiers for practical quantum applications.